Radon & Radon Decay Product Measurement Course

Center for Environmental Research & Technology, Inc. 1032 N Wahsatch Ave • Colorado Springs, CO 80903 800‐513‐8332 • www.certi.us

Chapter 1: Overview

Center for Environmental Research & Technology, Inc.

Radon and Radon Decay Product Measurement Course Chapter 1: Overview

Radon and Radon Decay Product Measurement Course

Developed by the Center for Environmental Research and Technology, Inc.

©© CERTI CERTI 20152015

Radon and Radon Decay Product Measurement Course

Chapter 1: Radon Overview

Radium

Uranium

Center for Environmental Research and Technology, Inc.

Radon Created from Breakdown of Natural Deposits of Uranium and Radium

 Radon is a gas  It is naturally occurring  It is inert  It cannot be seen or smelled Radon  It enters a building from the soil beneath Radium

Uranium

How Is Radon Drawn Into A Building?

 Vacuum Exhaust systems Thermal stack effects

80 Radon pCi/L 60

20 Vacuum (pa.) 0 1234 Days

Radon Can Be Elevated in: Low Radon Potential Homes  New homes  Old homes  Leaky homes  Homes without basements Unless you live on a houseboat or in a tree house,  Apartment buildings your home can have elevated  Schools levels of radon!  Offices

Radon Measurement Units

 Radon in air is measured in terms of: picoCuries per liter of air (pCi/L)  Curie: the amount of radiation generated from 1 gram of radium  One pico Curie: • One trillionth of a curie • 2.2 disintegrations per minute  Radon can also be measured in units of Bq/M 3 Becquerel per cubic meter SI units (Canada and Europe) 37 Bq/M 3 = 1 pCi/L

EPA & Surgeon General Recommend That People Not Have Exposures Above 4 pCi/L On A Long-Term Basis

Long-term exposure to radon increases the potential for Lung Cancer

Radon Reference Levels Situation U.S. Action Level 4.0 pCi/L Average Outdoor Radon Levels 0.4 pCi/L Average Indoor Levels 1.25 pCi/L Level below which most homes can be mitigated 2.0 pCi/L % U.S. Homes Above 4 pCi/L 15 % (1 in 6)

Guidance Levels 6.0 5.4 • Canada: 200 Bq/m3 4 4.0 • 200/37 = 5.4 pCi/L 2.7 • World Health Org: 100 Bq/m3 2.0 • 100/37 = 2.7 pCi/L Radon pCi/L) 0.0 Canada/Europe U.S. WHO © CERTI 2015

EPA Radon Zone Map

EPA: 1993  Based on geology and survey results  Expected short term radon (pCi/L):

 Zone 1 > 4.0

 Zone 2 > 2 < 4.0

 Zone 3 < 2.0

Many parts of the country have radon concerns! All Homes should be tested! © CERTI 2015

Radon Distribution

 Radon enters from beneath foundation and travels upward

 Diluted with outdoor air infiltrating building  Reduces exposure on upper levels  If radon is less than 4 pCi/L in lower level, one can say with reasonable confidence that upper floors are also less than 4 pCi/L Radon levels are typically highest in lowest level If not, an unusual entry mechanism may exist © CERTI 2015

Test Purpose Dictates Conditions

 Radon Potential:  Occupant Exposure:

 Short-term test  Long-term test

 Typically 2-5 days  Typically 91 days to 1 year

 Closed building conditions  Normal lived in conditions 12 hours prior to and all without special closed building during test conditions.

 Device deployed on lowest  Device deployed on lowest occupiable level of home. occupied level of home.

 Commonly used at time of  Commonly used outside of resale. resale, or as basis of escrow fund release.

Common Short-Term Passive Test Devices

 Used to determine radon potential Activated Charcoal  Commonly used at time of sale  Deployed for 2-5 days  Deployed by consumers and professionals alike

Electret Ion Chamber

Continuous Monitors

 Unusual swings can help identify  Provides hourly measurements concerns  Interpretation based upon average  Variations can indicate tampering

Successive 2-Day, Short-Term Measurement Results in Same House Over a three-month period, short-term real estate style 7 tests varied from 1.9 to 6.0 pCi/L.

2 2-Day Averages (pCi/L) Averages 2-Day

0 Average for entire period was 3.8 pCi/L Source: Dr. Dan Steck, Minnesota Radon Project Jan-March 1995 © CERTI 2015

Long-Term Tests Indicate Occupant Exposure

 Placed for a minimum of 91 days  No special closed building conditions  If result is equal to, or greater than 200 Bq/m3, mitigation is recommended

Alpha Track Detector Electret Ion Hang at least 12 inches Chamber down from ceiling

Test Location Depends on Purpose

Lowest lived in Non-Real Estate

Suitable for Real Estate Occupancy Lowest lived in

Bedroom Bedroom Kitchen • Choose occupied room YES YES NO Garage • Only 1 room necessary NO Bedroom Closet Living Room Bathroom NO YES YES NO

Test Placement Within A Room*

 Breathing Space

 Away from areas of spatial highs or lows  Where it will not be disturbed

Ceiling

Obstacle Minimum 12 inches Distance From (inches) Wall 3 feet from Opening (window or door) Floor 20 Interior 4 Ceiling* 12 inches Exterior: Interior wall 4 12 inches 20 inches Exterior wall 12 Floor Other objects 4 Minimum Distances from Features * AARST Protocol not in EPA Protocols

* Regardless of test duration or device © CERTI 2015

Measurement Strategy: EPA Citizen’s Guide (Homeowner) Short-Term Test Step 1 Equal to, or No greater than 4 pCi/L? No Mitigation Yes ST > 8 pCi/L ST <8 pCi/L Step 2 Follow-up Test Repeat Short-Term Long-Term Test

No Average of Results of No Yes Yes No No Mitigation 1st and 2nd results long-term test Mitigation Recommended at or above at or above Recommended 4pCi/L? 4 pCi/L? Mitigate Home

Real Estate Testing Option: Simultaneous Tests

Two Simultaneous Tests

YES NO Mitigation Average of Both No Mitigation Recommended Tests > 4.0 pCi/L Recommended

Real Estate Testing Option: Sequential Testing

Initial Short-Term Test 1

Second Short-Term Test

YES NO Mitigation Average of Both No Mitigation Recommended Tests > 4.0 pCi/L Recommended

Real Estate Testing Option: A Single Continuous Monitor

48 hour test with Continuous Monitor measures and reports in increments of 1 hour or less

Mitigation YES NO No Mitigation Average > 4.0 pCi/L Recommended Recommended

Radon Mitigation Overview (Movie Clip 11 min)

Radon Mitigation Works!

10 Mitigation System Off Mitigation System ON 9 8 7 6 5 4 3 EPA Guidance Radon (pCi/L) Radon 2 1 0 1:00 4:00 7:00 1:00 4:00 7:00 2:00 5:00 8:00 16:00 19:00 22:00 10:00 13:00 16:00 19:00 22:00 10:00 13:00 16:00 19:00 22:00 Hour

Is getting below 4.0 pCi/L the only consideration?

Discharges Should Be Above Roof

Discharge

Discharges to be Away From Openings

Discharge © CERTI 2015

Discharges Carry Moisture

Fan Location EPA Standards: Fans Should be Outside Living Space

Leakage on positive pressure side of fan can introduce radon into building

Use Solid PVC!

Dryer vent in Attic?? Caused Leak Through Ceiling

Unique Systems

Electrical

 Disconnects  Tapping into existing circuits  Non-rated fans  Licensed electrician?  Fan supports  Permits?

Labeling

 What should it say?  How durable should it be?  Where should it be?

Documents

Citizen’s Guide Homebuyer’s and Consumers Guide to Seller’s Guide Radon Reduction

Available within course and at EPA website © CERTI 2015

State Programs

 Many States have active radon programs that may have their own disclosure information and even different measurement protocols.

 Several States have their own certification programs that may require separate exams and certification application.

California Iowa New Jersey Delaware Kentucky Ohio Florida Maine Pennsylvania Illinois Nebraska Rhode Island Indiana New Mexico West Virginia © CERTI 2015

Certifications for Radon Professionals

Residential Measurement Provider: Standard Services (S)

 Place radon measurement devices (in homes) analyzed by NRPP certified laboratories or analytical service providers

 Interpret results for homeowners

 Two year certification

 Renew with CE Courses

 Certification initially requires course and exam passage

 Renewal requires continuing education to maintain

Residential Measurement Provider: Standard and Analytical Services (SA)

 Places the device AND generates radon results

 Everything a Standard Service provider must do

 Course, exam, 2 year certification, CE, etc

 Must demonstrate ability to measure and calculate radon

 Device specific

 Performance Test

 QA/QC plan

Analytical Laboratory (AL)

 Analyzes measurement devices placed by:  Certified measurement professionals  The general public  Requires a responsible party, certified as a measurement service provider.  Requires QA/QC plan and performance tests.

Residential Mitigation Service Provider

 Designs and installs radon mitigation systems

 Installs active soil depressurization systems in single family dwellings.

 Requires course attendance, passage of exam, and adherence to Radon Mitigation Standards.

 Advanced Large Building Mitigation

 Installs active soil depressurization systems and ventilation-based systems in single family dwellings and larger buildings.

To Become Certified with NRPP 1. Pass approved entry level course 2. Pass the NRPP Certification Exam 3. Complete and send in application to NRPP

 Include copy of course certificate and exam results

 Include appropriate fees

 You will receive NRPP ID Number and ID card (with photo if desired)  You will be listed on the NRPP site

 Some states will also list you on their site Some states have additional requirements and/or state certifications. Check with your state radon contact.

Steps to Certification 1. Pass approved entry level course 2. Pass the Certification Exam

 NRPP – Available at testing centers around country

 NRSB – Paper & pencil via prearranged proctor

 Some states like New Jersey and Florida administer their own exams 3. Complete and send in certification application

 Include copy of course certificate and exam results

 Include appropriate fees

Additional Steps to Certification

 If you analyze devices, you will need to prove you can utilize the device - Performance Test

 State Certifications*

 Some states require administrative steps beyond those required by NRPP or NRSB

 QA/QC Plans

 You must prepare a QA/QC plan

 Some states require submission of plan and periodic submittal of data

* www.CRCPD.ORG © CERTI 2015

All right lets get started!

Radon & Radon Decay Product Measurement Course

Chapter 2: Radon Entry

Center for Environmental Research & Technology, Inc.

Radon and Radon Decay Product Measurement Course Chapter 2: Radon Entry

Radon and Radon Decay Product Measurement Course

Chapter 2: Radon Entry

Center for Environmental Research and Technology, Inc. © CERTI 2015

Radium Turns Into Radon, Which As a Gas, Can Leave the Soil and Enter a Home

 Radon is a gas  It is naturally occurring  It is inert Radon  It cannot be seen or smelled  It enters a building from the Radium soil beneath

Uranium

Why Is Radon a Concern?

 Radon decays into radioactive particles known as radon decay Radon Decay Products products  These particles are Radon easily inhaled and deposited in the lungs where they can damage Radon sensitive lung tissue

Mechanism of Lung Cancer Induction

 Radon and RDPs inhaled  Radon exhaled  RDPs remain stuck to lung tissue  Po-218 and Po-214 emit alpha particles  Alpha particles strike lung cells causing physical and/or chemical damage to DNA

Initial Focus: Radon

 Radon Decay Products represent exposure risk  A radon measurement is a surrogate measurement of radon decay product exposure risk  Reducing radon entry into building will also reduce radon decay products

 Hence, the initial focus will be on radon gas entry

Factors Influencing Radon Levels in Homes

 Source Largest Impact  Driving Force Impact Decreasing

 Pathway

 Openings in Foundation

 Ventilation Rate

Radon Generating Geology is the Primary Determining Factor

 If there is no radon generated under the building, regardless of how much soil air can enter the building, there will not be an indoor radon concern

 The larger the source under the building, the greater the effect that entry patterns will have

 The higher the source the greater the variability will be

Radon Potential Maps

 Elevated Indoor Radon can generally be related to underlying geology, but not always  Be very careful - it is the exceptions that get you

Soil Gas as a Source of Radon

 Natural soil and rock near or beneath building

 Granites, shales, and corals, etc. can have slightly elevated levels of uranium (approx. 5 pCi/g)

 Contaminated soils from uranium processing mills, and contaminated building materials

 Relatively rare and well known in the local area if present

Factors Influencing Potential of Radon Source

Rn Rn Ra Rn  Radium content Ra  Particle size: the smaller the Rn Ra particles the more surface area Ra Rn for disengagement

soil, rocks or geology beneath building

Radon Concentration in Soil Gas Varies From Location to Location

Soil Gas Measurements pCi/L in Soil Gas

12,664 668

Variances within very short House Footprint 111 77,194 distances depending on:  Concentration of radium 351 89,100  Airflow through soil 112 Readings can be misleading

Where was the main source of radon? © CERTI 2015

Radon Entry Varies From Building to Building

Clay Sandy Soil Strong Source

2,400 pCi/L 3 pCi/L

All Homes Should Be Tested!

Forces that Cause Radon Laden Soil Gas to Enter Buildings

• Stack Effect • Soil Pressures • Building HVAC Systems

Its all about pressure differentials

Building Induced Suction on the Soil Is a Predominant Overall Driving Force

 Vacuum

 Exhaust systems

 Thermal stack effects

80 Radon pCi/L 60

20 Vacuum (Pa.) 0 1234 Soil pressures can also push Days

radon into building © CERTI 2015

Radon Distribution

 Radon enters from beneath foundation and travels upward

Radon levels are typically highest in lowest level If not, an unusual entry mechanism may exist © CERTI 2015

Pressure Differential - Neutral Neutral Pressure  Difference in pressure between inside and outside of the home  Measured in inches of water column (or pascals)  Distance between water level on one side versus the other side of a water filed manometer  In this case no difference in pressure

Pressure Differential-Negative Vacuum or Negative  Difference in pressure Pressure between inside and outside of the home  In this case an exhaust fan has been turned on pulling air out of house

Pressure Differential - Positive Positive Pressure  Forced air make-up to building can pressurize interior relative to outside as well as soil

 Retards soil gas entry

 Common in large buildings (when ON)

 Swamp coolers (rare) will also do this

Pressure Differential - Interior to Subgrade Vacuum or Negative  A difference in pressure Pressure between house and subgrade impacts soil gas entry  Interior vacuum

 Brings radon in  Sub grade pressure

 Pushes radon in  Interior pressure

 Retards radon entry

Magnitude of Pressure Differentials in Homes

How much vacuum would you 3 inches need to exert to drink water through a straw from this glass?

 Differential pressures across shell or across slab are typically on the order of thousandths of an inch rather than full inches.

 Area of soil influence localized to beneath and around perimeter (2- 5 meters from house)

 Easily impacted by weather, exhaust fans etc.

Differential Pressure Measurements English Units (U.S.) SI Units (Canada) Inches of Water Column Pascals

Most instruments can measure in either unit

Switch

1 pascal = 0.004 inches of water column A thousandth of an inch is ¼ of a pascal © CERTI 2015

Micromanometer  Measures pressure difference between two ports on instrument (arrows in picture)

 Tube connected to one port and placed in hole through slab (measured variable)

Ports  Second port open to room (reference)  Result is “relative” to the port open into room

 If positive, then soil is more positive than interior OR interior is more negative than soil

Smoke Bottles

 Can show what is “negative” and what is “positive”

 Direction of air flow Smoke being drawn  Not quantitative but down through opening in foundation provides quick and easy indicator of positive or negative pressure differential

Temperature Induced Pressure Differential: Stack Effect

 Cold outside air is denser and moves down

Warm, light through soil, entraining Cold, dense inside air soil gasses (radon) as it outside air enters house  Air entry via soil can entrain radon

Stack Effect at Different Outdoor Temperatures

0.020 Outside Temperature 0F 0.000 0 1020304050607080 -0.020 Radon Can Enter -0.040

-0.060 A soil gas collection system must be

-0.080 able to provide a vacuum under the Interior Pressure H2Oofinches Pressure Interior slab that can overcome this negative pressure as well as effects of Three Story House at 68 Degrees 0F exhaust ventilation.

Stack Effect Effect of Building Height

 Interior vacuum pulling on soil T o gases: = Outside = Outside Temperature

 Increases as outside temperature drops

 Increases with building height

Neutral Pressure Plane  Location in house where interior pressure goes from negative to positive

Effect of NPP Location + NPP  Length of Arrows in diagrams - indicate strength of positive or negative pressure  The lower the NPP the greater the vacuum is in the lowest portion of home contacting radon laden soil  The location of the NPP is a function of where building leak

NPP points are

Effect of Open Window

 Drops Neutral Pressure Plane  Reduces vacuum on lower soil contacting portion of foundation  Dilutes indoor radon levels

Effect of Wind on NPP

 Wind can cause NPP to tilt  If majority of leakage is on downwind side the entire house can go negative and increase radon entry *

* Gulland.ca © CERTI 2015

Wind Against Hillside can Force Radon to Enter! Wind 50 40 30 20 1000) 10 0

Sub slab pressures (in W.C.x (in W.C.x pressures Sub slab -10

-20 Wind Direction S.E. N.E. East © CERTI 2015

Effects of Rain

. May cap the soil . May displace and force soil gas into building . May be accompanied by barometric pressure changes

Effects of Frost or Other Factors That Cap Soil

. Frost may cap the soil so negative pressure of building is exerted on a larger area . Asphalt aprons around large buildings may have the same effect

Mechanical Ventilation System of a Building Can Create Vacuum

 Heating Ventilation and Air Conditioning System known as HVAC  Air handling system can create vacuum

 Exhaust fans

 Unbalanced air flow

 Leaky furnace/air conditioning ductwork

 Sub slab ductwork

Estimated Air Flows for Typical Home Exhaust Systems

Typical CFM Bathroom Fans 24 - 90 Clothes Dryer 100 Central Vacuum 110 Wood Fireplace 170 Open Wood Stove 65 Air-Tight Wood Stove 30 Combustion Appliances 21 - 72

Whole House Fans

 Create significant vacuums  Designed to run with windows open  Should not be operated during short-term radon measurements

Evaporative Coolers Pressurize Building

. Evaporative Coolers (swamp coolers) . Used for cooling in dry climates . Pressurize buildings . Should not be operated during short-term radon measurements

Effect of Leaky Ductwork & Unbalanced Home HVAC

 Leaks in return create vacuums in specific levels of home  Levels of home with no supply vents may have high vacuums

Return Ducts Beneath Slab

 HVAC fan draws radon into leaky ducts  Highest entry when fan is on

Fresh Air HVAC Fan

 Supply ducts can also be below slab  Sub-slab ducts are more common in big buildings

Fresh Air Make-up – Large Buildings Newer Homes

Return Air Exhaust Air Coils Supply Air Fan Outside Air

Classroom Classroom

Effect of Fresh Air Make-up in Schools

Hourly Variations 18 Averages by Period

16 12

14 9.1 12

10 8

8 5.9

Radon (pCi/L) Radon 6

4 Radon pCi/L 4 2 1.7 0 0 1:00 AM 1:00 AM 3:00 AM 5:00 AM 7:00 AM 9:00 1:00 AM 1:00 AM 3:00 AM 5:00 AM 7:00 AM 9:00 1:00 PM 1:00 PM 3:00 PM 5:00 PM 7:00 PM 9:00 PM 1:00 PM 3:00 PM 5:00 PM 7:00 PM 9:00 PM 1:00 PM 3:00 11:00 AM 11:00 11:00 AM 11:00 AM 11:00 11:00 PM 11:00 11:00 PM 11:00 Total Unoccupied Occupied Radon Occupied Period EPA Guidance

Occupied periods assumed to be: 7:30 AM to 3:30 AM / Hourly measurements are average for preceding hour Test Period: April 18-20, 2007 - Post HVAC adjustments Pre-HVAC ST Measurement: 6.0 pCi/L overall © CERTI 2015

Unit Ventilators

Supply Air

Outside Air Water or Steam Coil

Return Air

Small HVAC systems for individual rooms Fresh air could be restricted Leaks around plumbing penetrations

Example of Outdoor Air Being Defeated

Air Inlet Intentionally Damper Control Disabled Blocked

Filter or Coil Condition Can Impact Outside Air Make-Up

Impact of Outdoor Air on Individual Rooms-Large Buildings

 HVAC systems can serve:

 Zones within a building  One zone may have more outdoor air than another

 Individual rooms  Air damper controls may not be functional  Freeze-stats that prevent coil freeze-up may have closed  Filters may be dirty and be reducing intake

A very good reason why all rooms that have potential for radon entry should be tested, rather than just a random, statistical sampling! © CERTI 2015

Example: Why is central pod higher than others?

 Each pod served by separate HVAC system  Outdoor air in central pod was minimized

Why Some Classrooms Were Elevated and Others Were Not

Original Units with Fresh Air Make-up Fresh air make-up disabled when FAU replaced © CERTI 2015

Take Away Message for Outdoor Air Large Buildings 1. Avoid scheduling tests when economizers are operating  False negative 2. Avoid short-term tests during periods when outside air is primarily off  Schools and Commercial buildings:  Avoid weekends  Avoid holidays 3. A room that tested low this year could be high next year, if outdoor air is shut off or controls not maintained

Testing During “Off” Periods

 Very tempting – but inadvisable  Early school testing was performed in this manner

 EPA revised school protocols to while school in session

 Many old school reports are of questionable value

Effect of Unbalanced System

Mixing Fresh Chamber Outside Air Blower Filter Heater Supply

Return

Room 2 Room 3 Room 4 Room+ 1 - - +

Example: Unbalanced Ductwork

 Room divider added

 Supply on one side

 Return on other side

Return Air Plenums

Plenum Open to Soil

Supply Air Classroom

Outdoor Air Damper Radon conveyed into room (Was initially closed) Return- Plenum Radon laden soil gas entering through cracks in concrete floor within plenum © CERTI 2015

Ceilings as Return Air Plenums – Uh Oh!

Roof

Ceiling Stud Wall Exterior Wall Exterior Wall

Stud Wall Stud Occupied Space

Slab

Radon Radon

Pipe Chase open to dirt Leaky Plenums in Apartments

- - Leak Low Radon Potentially High Radon

- -

Leak High Radon Low Radon - + + Soil Radon © CERTI 2015

Return Ducts Beneath Slab

 HVAC fan draws radon into leaky ducts  Highest entry when fan is on

Fresh Air HVAC Fan

 Supply ducts can also be below slab  Sub-slab ducts are more common in big buildings

Pathways and Structural Considerations

If the building is in contact with soil that contains radon, the structure can have a radon concern regardless of the type of foundation!

Many Pathways for Radon to Follow

 Natural

 Pores or void space in soil, i.e., permeability of underlying soils

 Cracks, fissures in underlying geology  Man-made

 From loose fill beneath foundation

 Along utility line trenches

 Along and into water drainage systems (e.g., sumps)

Man-Made Pathways

 Construction process can disturb native fills and make them more permeable.  Utility lines and water collection systems often lay in trenches with loose fill or gravel.

Slab Penetrations

 Plumbing block-outs for tubs, commodes, showers, etc.  Most are hidden during construction  Radon follows loose fill in plumbing trench and is drawn in through slab opening.

Radon Entry Through Water Drainage Systems

. Radon can pass through Upper Floor of Home porous drainage beds or “French Drains” toward Sump Discharge home

Sump Pit Sump Pump . Frequently routed to interior sumps

Soil Gas Soil Gas Perforated Foundation Drain CVC ©

Foundation Type: Pier Building on “Stilts”

. Generally open to outside air, however, on a hill one or more sides may be bermed in . Mobile homes are set on piers which may be skirted and insulated

Foundation Type: Crawl Space Built Over Enclosed Earthen Area

. Large opening where vacuum from house is applied . Crawl vents are little help, especially in winter . Floor insulation is not a radon barrier

Foundation Type: Slab-on-Grade Foundation Walls

Many openings  Cracks Slab  Penetrations  Joints Concrete  Block Poured Cold, expansion Wall Concrete Wall Hollow blocks

Aggregate/Sand Undisturbed Soil Footing Plumbing Penetration

Foundation Type: Slab-on-Grade Monolithic Pours

Monolithic Plumbing Concrete Penetrations Pour Floor Drain

. Trench dug for footing and poured with floor . Common in temperate climates . Cracks and penetrations provide openings

Floor-to-Wall Joints Can Be Major Entry Points for Slabs

. Soil around footing is disturbed and permeable . Extends completely around Cold Joint perimeter . Interior finishing does not stop Channel Drain radon

Expansion Joint

Foundation Type: Basement Poured and Block Walls

. Cracks and penetrations in poured floors/walls . Blocks may be hollow, allowing radon to enter through sides and top row . Excavation makes soil more permeable

Effect of Ventilation Rates on Radon Concentrations

 After radon enters a structure, it is diluted with indoor air  The more fresh air entering a home, the lower the final radon concentration  Low ventilation rates (tight homes) do not cause radon concerns, but do reduce the amount of dilution  Weatherization efforts when combined with addition of controlled fresh air does not increase indoor radon

Other Radon Sources of Entry

Mechanism: Diffusion - Movement of Radon Through Materials

Low . Caused by gradients in Concentration of Radon concentration between building’s interior and Rn Rn underlying soil . Generally a low entry rate . Usually dissipated by normal ventilation

High Concentration of Radon

Mechanism: Emanation – Release of Radon From Surface of Materials

. Rocks and building materials can contain uranium and radium . Radon created on surface is emitted into room . Rate depends on radium content and surface area . Usually dissipated by normal ventilation Rn Ra Ra Rn

Mechanism: Outgassing From Well Water Supply

. High radon entry may be isolated to well . Can be significant Rn Rn . More radon released during use of hot water w . Buildings with water supplied from groundwater are of highest concern Ra

Radon Transport via Water Supply

 Radon enters water in 12 aquifer  Radon outgasses from water Rn 8 in when used Air (pCi/L) 4  Once in building, radon is diluted in air 0.4  10,000 pCi/L in water 8,000 24,000 40,000 56,000 72,000 8,000 24,000 40,000 56,000 72,000 generally yields 1 pCi/L in Radon in Water (pCi/L) air after dilution

Question A house determined to have indoor radon levels of 18 pCi/L. Sampling of the water supply indicates 23,500 pCi/L of radon in the water supply. What is the primary source of radon?

 Roughly 2 pCi/L is coming from the water

 23,500/10,000 = 2.35

 The other 16 pCi/L is coming from another source than the water!

 18-2 = 16

 More than likely from the soil

Mechanism: Direct Entry of Soil Gas - Convective Air Flow

 Building’s vacuum or soil pressure causes air from soil to enter through openings in foundation  Soil gases enter all buildings. If the soil has radon, it enters with the soil gases  This is the primary entry mechanism!

Average Contributions from Radon Sources in U.S. Homes

. The movement of soil gas into a home is the predominant entry route for radon Water Emanation . These are only averages - < 1% 2 - 5% Soil Gas every home may be different! 85 - 90% Diffusion 1 - 4%

Radium-ContainingRadium Containing Soil

Mapping Potential Radon Areas

Be Careful!

Radon Surveys and Mapping of Potential Areas of Concern

 U.S. EPA began performing surveys in 1986 to better understand the extent of radon concerns  Generally, areas high in radon can be associated with radium rich soils  Some areas not expected to have significant problems due to geology, have indicated high radon potentials and thus implicated the relationship of other factors

Early Mapping

 Granites Extent of last glaciation  Shales  Phosphatic rocks Granites  Based largely upon uranium exploration Shales experiences

Phosphatic rocks

1993: Radon Zone Map by County

Based on geology and survey results Expected short term radon (pCi/L):  Zone 1 > 4.0  Zone 2 > 2 < 4.0  Zone 3 < 2.0

U.S. Radon Levels

Situation U.S. Action Level 4.0 pCi/L Average Outdoor Radon Levels 0.4 pCi/L Average Indoor Levels 1.25 pCi/L Level below which most homes can be mitigated 2.0 pCi/L % U.S. Homes Above 4 pCi/L 15 % (1 in 6)

Data above provides basis for one of the assumptions for health risk estimates

Variability of Radon Concentrations in Homes

Radon Levels Are Typically Higher In Lower Level of Home

90 Basement First Floor . Higher radon 80 found in upper 70 floors (rather than 60 in lower floors) 50 can indicate 40 unusual entry 30

Radon pCi/L mechanisms 20 10 0 LBL12 11/15 12/24 1/17 2/17 3/1 3/13 3/28 4/23 to to to to to to to to 11/24 1/2 1/29 2/20 3/6 3/19 4/2 4/30 © CERTI 2015

Variations of Radon Concentration in Homes

 For rooms on the same floor, radon concentrations do not vary significantly from one room to the next  Only one test location in lower floor of home is necessary

 Significant room-to-room variations on ground floors occur in large buildings (where large imbalanced HVAC systems may cause significant mechanically-induced vacuums)  Radon concentrations decrease on upper floors

Overall Radon Entry Is Seasonal

Seasonal Changes (Cold Climate) Entry rates can be higher in: . Cold climates during winter . Hot climates during summer (no evaporative coolers) . Tropical climates or areas with Winter limestone geologies during Summer rainy season Long-Term Radon (pCi/L) Radon Long-Term

Radon Entry Is Variable Because The Driving Forces Are Variable

30 Pressure differentials can change rapidly

20 . Change in temperature . Change in weather Rn . Occupant use of exhaust pCi/L 10 equipment . Seasonal variations Minimum two day integrating 0 measurements 0 24 48 72 96 120 Time (Hours) © CERTI 2015

Unit Summary: Radon Entry and Indoor Concentrations Are Variable

Hour to Hour Season to Season Building to Building Floor to Floor The only way to properly characterize a building’s radon potential is to follow recognized testing procedures!

Radon & Radon Decay Product Measurement Course

Chapter 3: Physics of Radon

Center for Environmental Research & Technology, Inc.

Radon and Radon Decay Product Measurement Course Chapter 3: Physics

Radon and Radon Decay Product Measurement Course

Chapter 3: Physics of Radon

Center for Environmental Research and Technology, Inc.

How Does This Happen?

 One element turning into another!

 Sounds like alchemy!  Radon is inert!

 How can that hurt you? Radon  It cannot be seen or smelled!  If you can’t see it or smell it, how do you even know it is there? Radium

Uranium

Let’s get a little technical

Model of an Atom

 Nucleus

 Protons (+)

 Neutrons (neutral)

 Electrons (-)

 The number of electrons is normally equal to the number of protons, so the total atom has no net charge

Atoms Combine to Form Molecules

 Share electrons  Characteristics for forming molecules are based on number of electrons and their configuration  Since the number of electrons are typically equal to the number of protons, the number of protons defines the characteristics of the atom  Some atoms are configured in such a way that they do not share (inert gases)

Periodic Table of the Elements (1)

 Organizes elements by chemical characteristics

 Interaction with other elements

 By number of protons

 If number of protons change, then atom changes the way it interacts with others and hence called a different element © CERTI 2015

Periodic Table of the Elements (2) . Radon behaves like an inert gas . Does not combine chemically with other atoms to form molecules . Allows it to move freely through soil . Its nuclear configuration is unstable . Will easily lose 2 protons, causing it to change its characteristics to that of another element (polonium) Rn 86 222

The Nucleus

 The nucleus is made up of positively charged protons and neutral neutrons.  Protons have like charges and repel each other  Neutrons are the “glue” that holds the nucleus together.  The number of protons is the atomic number (and identifies the element)

 If the number of protons change, it is referred to as different element  The number of protons and neutrons combined is the atomic mass

A Radon-222 Nucleus

 Protons = 86  Neutrons = 136  Atomic Mass = 222  Atomic Number = 86  This atom of radon is further identified Although chemically inert, the radon by its atomic mass, nucleus is unstable (not enough glue) and will easily lose protons after hence the name being formed. radon-222

Radioactive Decay

. Spontaneous Radium-226 . Atom changes identity Alpha due to a change in the Radiation number of protons Gamma Radiation (loses 2 protons) . Other radiation is released in the process . Gamma released as protons and Radon-222 neutrons realign

Uranium-238 Radon-222 Bismuth-210    Thorium-234 Polonium-218 Polonium-210    Protactinium-234 Lead-214 Lead-206   (Stable) Uranium-234 Bismuth-214   Thorium-230 Polonium-214 Uranium 238   Radium-226 Lead-210 Decay Series  

Three Types Of Radiation Released as radon and short-lived radon decay products decay + Alpha α + Beta β -

Gamma γ Causes damage and also provides a signal for γ measurement devices to detect when α β radioactive decay occurs

Alpha Radiation ()

 Alpha radiation is a particle released when the nucleus kicks out 2 neutrons and 2 protons (atomic mass changes by 4 and atomic number changes by 2)

 Alpha particle

 relatively massive

 relatively slow

 total charge of +2  Alpha particles cause 20 times more cell damage per impact than beta or gamma

Alpha Particles are Strong Enough to Pit Plastic

 Plastic chip from passive radon test (alpha track)

 Magnified only 100 times

 3 months at EPA Action Level of 4 pCi/L

Photo: Dr. J.F. Burkhart

Beta Radiation (ß)

 Beta Radiation is a particle that is released when the nucleus changes a neutron into a proton and a beta particle (atomic mass remains unchanged)  Beta particle

 relatively small mass

 relatively fast moving

 total charge of -1

Gamma Radiation ()

 Gamma radiation is pure energy. It is released from the nucleus whenever an alpha or a beta is emitted.  Gamma ray

 No mass

 Moves at the speed of light

 No charge

Relative Penetrating Power

Alpha

Beta

Gamma

Paper Concrete Alpha causes the largest damage per single impact! © CERTI 2015

Radon Radioactively Decays

. Relatively soon after it Radon-222 is formed Alpha . Long enough for it to travel Radiation short distances in soil Gamma Radiation . Changes characteristics to that of Polonium-218 Polonium-218 . Po-218 is also unstable and is Alpha an alpha emitter Radiation Gamma Radiation

Radon and Radon Decay Products Radon-222 Alpha α

Polonium-218 Alpha α Short-Lived Beta β Radon Lead-214 Gamma γ Decay Products Beta β  Bismuth-214 Gamma γ Polonium-214 Alpha α Beta β

Relatively Stable Lead-210 Gamma γ © CERTI 2015

Radon Decay (Short-Lived) Radon-222 Alpha Protons: 86

Polonium-218 Alpha Protons: 84

Lead-214 Beta Protons: 82 Gamma

Bismuth-214 Beta Protons: 83 Gamma

Polonium-214 Protons: 84 Alpha © CERTI 2015

Short-Lived Decay Series Pinball Analogy

Rn-222 Higher Energy State Less Stable

Po-218

Pb-214 Bi-214 Lower Energy State More Stable Po-214

Pb-210

Secular Equilibrium Analogy

1 2

In a construction zone where a flagman is controlling the rate which cars pass, what is the rate that cars are getting through the construction area?

 Alt 1: Count the cars as they pass the flagman, or

 Alt 2: Count the cars a ½ mile down the road as they pass by you sitting under a shady tree.

Since the flagman is the controlling variable (longest half life), counting cars as in Alt 2 works when Secular Equilibrium has been achieved.

At Secular Equilibrium the Decay Rates of RDPs and Radon Are Equal

Radon 222 - 3.8 days Po 218 - 3 min. Pb 214 - 27 min. Bi 214 - 19.7 min. Po 214 - .000164 sec.

Pb 210 - 19.7 years

Secular Equilibrium

 It takes four hours for a sufficient number of RDPs to form and come into “radioactive equilibrium” with the radon

 Some devices cannot be analyzed until the four hour waiting time occurs

 Activated charcoal  Some continuous monitors  Grab samples

Rate of Decay Expressed as Half-Life

100%

and 50% so on 25% 12.5% 6.25% 1 half-life 2 half-lives 3 half-lives 4 half-lives

 Half-life is the amount of time for one half of a radioactive substance to decay to another  Delaying analysis of device reduces radioactive “signal” from measurement devices that rely upon radioactive measurements

 Charcoal, Liquid scintillation © CERTI 2015

For Example:

 Radon has a half-life of 3.8 days (~4)  If we collected 1 gram of radon in a container on June 1, how much radon would be in the container on June 9, of the same year?  How much would be left as of June 17, 2015?

Consequence of Half Life on Measurement Accuracy

 Measurement devices either:

 Measure radioactivity of radon collected after measurement period  The longer the delay between measurement and analysis the harder radioactive “signal” is to discern  Activated Charcoal, Liquid Scintillation, Grab Radon

 Record radioactive decay during measurement period  Radioactive decay is recorded so “signal” does not deteriorate with time  Continuous Monitors, Electret Ion Chambers, Alpha Tracks

Ionization Caused by Radiation Can Occur with an , , or  Atom Ion (net charge +1)

Before Collision After Collision

Recoil from Alpha Release Strips Electrons Causing Resultant Decay Product to be Charged

Stripped Electrons + Ion Alpha particle

Radon Decay Radon Atom Product © CERTI 2015

Ion

 Normally, the number of electrons orbiting the nucleus is equal to the number of protons inside the nucleus, so the total charge of the atom is zero

 An ion is an atom that has either lost or gained electrons. It has a net positive or negative charge

Impact of Ionization

 Measuring ionization allows one to detect the presence of radiation  Pulsed ion chambers, electret ion chambers, Geiger counters

 Ionization also contributes to overall health effects  The type of radiation that comes from radon and its decay products is called “ionizing radiation”  You will commonly see reference to studies entitled: “Biological Effects of Ionizing Radiation” a.k.a.BEIR

Radioactivity

Radon-222 Rate that a radioactive element decays or disintegrates down Alpha to another element Radiation Gamma Type Unit Rate/Second Rate/Minute Radiation U.S. Pico Curie .037 decays 2.22 decays (pCi) per second per minute

SI/Canada Becquerel 1 decay 60 decays (Bq) per second per minute

Polonium 218

A source at 1 Bq is 27 times stronger than one at 1 pCi

(1/0.037 = 27) © CERTI 2015

Radon Measurement Units (air)

 Radon in air is measured in terms of:

 picoCuries per liter of air (pCi/Lair)  Curie: the amount of radiation generated from 1 gram of radium (2.2 disintegrations per minute)

 One pico Curie: one trillionth of a curie

 The pCi/L is not a measurement of physical concentration, but rather the “activity” or rate of energy released within a given volume of air.

Converting Between Bq/m3 and pCi/L

/ = pCi/L pCi/L x 37 = Bq/m3 Tips:

 Remember 37  To convert --- either multiply or divide by 37  If sampling same location -- Bq/m3 will always be numerically larger than pCi/L 3  Divide by 37 when converting Bq/m to pCi/L 3  Multiply by 37 when converting pCi/L to Bq/m

Conversion Examples: Bq/m3 to pCi/L

/ = pCi/L

 What is the Canadian radon guidance in pCi/L? / = 5.4 pCi/L

 What is World Health Organization’s Reference Level of 100 Bq/m3 in terms of pCi/L? / = 2.7 pCi/L © CERTI 2015

Conversion Examples: pCi/L to Bq/m3

pCi/L x 37 = Bq/m3

 What is the U.S. radon guidance in Bq/m3 ? 4.0 pCi/L x 37 = 148 Bq/m3

 What is U.S. EPA’s suggestion to which homes can be reduced when mitigated in Bq/m3?

2.0 pCi/L x 37 = 74 Bq/m3

Radon Decay Products (RDPs) The real culprits!

 Created when radon radioactively decays  Primary source of cell damage in lungs  Radon is breathed in and exhaled  Radon decay products, if inhaled, can stick to lung tissue  Short-lived  Deliver alpha impact directly to tissue to which it is attached  Solid, charged particles

RADON DECAY PRODUCTS (RDPs)

 Radon is drawn from the soil into the building  Radon mixes with the air

 This can be inhaled and exhaled without accumulation  When radon decays turns into radon decay products, they are still in the air  This creates an aerosol of radon decay Radon products in the air Radon  These can be inhaled, but because they have charges and act like solids, can be accumulated in the lungs

Radon Decay Product Units

 One Working Level is the amount of short-lived radon decay products that exist at any moment within one liter if a room, or

1 WL container, is constantly maintained at 100 pCi/L (assuming all RDPs that are 100 pCi/L Radon produced are measured).

Radon  0.020 WL has been criteria for clean-up efforts

Working Level (WL)

 Historically, a level of radon decay products in which miners were working (hence, working level)  Guidance: 0.02WL - Clean-up standard for sites contaminated with radioactive materials  Measuring radon decay products has historically been expensive

 Radon measurements were developed as a surrogate or substitute measurement for estimating radon decay product levels  RDP exposures are the primary basis for health studies and occupational exposures

What Happens to Radon Decay Products ?

 Radon decay products have electrostatic charges  If they come in contact with objects (walls, furniture), they stick to them  Called “Plate-out”  If plated out - no longer a health risk as RDPs RDPs they cannot be dislodged and reenter the breathing space Radon  The degree of plate-out affects the actual risk presented by a given Radon amount of radon  Greater plate-out = lower risk

Assumed Distribution Equilibrium Ratio Assumption

~40% Airborne  Breathable  Measurable Radon Decay Radon-222 Products Plated Out . To relate radon measurements to amount of radon decay products in the air, one  Non Breathable has to know or estimate the percentage ~60%  Non Measurable of decay products remaining in the air . Initially U.S. assumed to be 50% - Now assumed to be 40% throughout world © CERTI 2015

Equilibrium Ratio (ER)* Estimating Radon Decay Products from Radon The equilibrium ratio is the fraction (or percentage) of RDPs suspended in the air relative to the total RDPs Plated out RDPs created

Suspended RDPs Suspended ER = RDPs Total RDPs from Radon

* Nomenclature: Equilibrium Ratio (ER) = Equilibrium Fraction (EF) also (F)

Factors Affecting Equilibrium Ratio

 Air Circulation  Increases plate-out = Decreases ER

 Stagnant Air  Decreases plate-out = Increases ER

 Air Filters  Removes RDPs and those attached to dust particles = Decreases RDPs

 Suspended Dust / Smoke  RDPs attach to suspended dust before plating out = Increases ER

 Recent Ventilation  Inadequate time for RDPs to form © CERTI 2015

The Degree of Plate-Out Effects Health Risk from Radon

F=1.0 F=.5 F=.4 F=.3 F=.1

100% 50% 40% 30% 10% Suspended Suspended Suspended Suspended Suspended

OSHA EPA BEIR VI, Buildings w/air Buildings w/high Protocol Europe, Canada circulation air circulation, EPA Update clean air

F=Equilibrium Fraction or Ratio © CERTI 2015

Determining Equilibrium Factor

Radon Decay Products  Requires ability to Radon simultaneously measure radon and radon decay products

Effect of Air Circulation on Plate-out, Building With Central Air Handler

0.05 10 9 0.04 8 7 0.03 6 5 0.02 4 EPA Action Level

3 Radon (pCi/L) 0.01 2 1 Radon Decay Products (WL) RadonProducts Decay 0 0 1:00 4:00 7:00 1:00 4:00 7:00 1:00 4:00 7:00 16:00 19:00 22:00 10:00 13:00 16:00 19:00 22:00 10:00 13:00 16:00 19:00 22:00 10:00

Average Radon: 6.0pCi/L AVG RDPs: 0.007WL Percent in air (ER): 12%

Effect of Stagnant Air on Plate-out Unoccupied Residence, No Furniture, No Air Circulation

0.25 50 45 0.2 40 35 0.15 30 25 0.1 20 15 Radon (pCi/L) 0.05 10 EPA Guidance 5 Radon decay products (WL) products decay Radon 0 0 1:45 PM 1:45 PM 4:45 PM 7:45 1:45 PM 1:45 PM 4:45 PM 7:45 1:45 PM 1:45 PM 4:45 PM 7:45 1:45 AM 1:45 AM 4:45 AM 7:45 1:45 AM 1:45 AM 4:45 AM 7:45 1:45 AM 1:45 AM 4:45 AM 7:45 10:45 PM 10:45 10:45 PM 10:45 10:45 PM 10:45 10:45 AM 10:45 10:45 AM 10:45 10:45 AM 10:45

WL Rn EPA Guidance

Average Radon: 19.3 pCi/L AVG RDPs: 0.138 WL Percent in air (ER): 71%

Effect of Whole House Air Cleaner

700 Filter OFF Filter ON 0.07 600 0.06

) 500 0.05 3

400 0.04

300 0.03 RDPs (WL)

Radon (Bq/m Radon 200 0.02

100 0.01

0 0 8:40 0:40 2:40 4:40 6:40 8:40 0:40 2:40 4:40 6:40 8:40 0:40 2:40 4:40 6:40 8:40 10:40 12:40 14:40 16:40 18:40 20:40 22:40 10:40 12:40 14:40 16:40 18:40 20:40 22:40 10:40 12:40 14:40 16:40 18:40 20:40 22:40 10:40 12:40 14:40 Radon HEPA ON Guidance WL

Pre Air Cleaner: Rn: 377 Bq/m3 RDPs 0.036 WL ER: 35% Post Air Cleaner: Rn: 463 Bq/m3 RDPs 0.006 WL ER: 5%

Equilibrium Equation (English) A Means for Estimating RDP Levels from Radon Measurements Where Radon is Measured in pCi/L

WL x 100  ER = WL x 100 Rn

 Rn = WL x 100 ER ER Rn (pCi/L)  WL = ER x Rn 100

Equilibrium Equation Example 1 Calculate Equilibrium Factor If Rn = 6.8 pCi/L and RDPs = .042 WL what is EF?

. . ER = = 0.62 or 62%

Note: Percentage of decay products in air is referred to as equilibrium factor (EF) or Equilibrium Ratio (ER)

Equilibrium Equation Example 2 Calculate Radon

How much radon is needed to create 0.020 WL in a room assumed to have an equilibrium factor of 40% EF?

. Rn = = 5 pCi/L .

Note: U.S. has historically been 50% but more recently at 40% Canada (and others) assume an EF of 40% (0.4)

Equilibrium Equation Example 3 Calculate RDPs

If EF = 40% and radon is 22 pCi/L, what is Radon Decay

Product activity in units of WL?

(pCi/L) (pCi/L) Rn

ER ER

WL x 3700 Rn (pCi/L) WL x 100 x WL WL x 100 ER Rn (pCi/L)

. = = 0.088 WL © CERTI 2015

Equilibrium Equation (SI) A Means for Estimating RDP Levels from Radon Measurements Where Radon is Measured in Bq/m3

WL x 3700  ER = Rn WL x 3700  Rn = WL x 3700 ER

 WL = ER Rn ER x Rn (Bq/m3) 3700 / = pCi/L © CERTI 2015

Dose – Working Level Month WLM

 Working Level Month is a combination of exposure and duration of exposure:  This directly impacts the potential for lung cancer

 WLM =

* 170 hours per working month is an average assumed by Mine Safety and Health

Dose Example What is the dose in WLM for working a full year (2,000 hours) in a residential environment at average radon level of 4 pCi/L, assuming a residential Equilibrium factor of 50%

1. Estimate RDP in WL using an EF assumption of 50% WL = RN x EF/100 = 4.0 x .5/100 = .020 WL 2. Determine Dose in WLM WLM = WL x hours/170 = .016 x 2000/170 = 0.235 WLM

What is Significance of Annual Dose to a Radon Professional?  EPA recommends not to exceed accumulative dose of 4 WLM/year  OSHA requires that controls begin at 1.0 WLM/year What radon environment could a person work in for 2,000 hours per year and not exceed 1 WLM/year assuming 40% EF?

1.0 WLM/Year = ? RDS x 2000 hours/170 Rearrange to: ? RDPs = 1.0 WLM/Year /2000 hours x 170 = 0.085 WL

. WL x 3700 Rn = = 21.3 pCi/L Rn . ER pCi/L © CERTI 2015

ER/EF Assumption

 The range in homes is typically from 30-70%

 In buildings with high circulation rates, the variance from assumption can be even higher  U.S. has historically used 50% but is now moving towards 40%  OSHA assumes 100%

 Conservative

 Would need to work at 8.5 pCi/L all year to reach 1 WLM

 Would need to work all year at 34 to reach 4 WLM

Dynamic Equilibrium

. Once the radon entry rate 12 Hours into a building has been Rn altered, time is needed for RDPs radon and RDP levels to stabilize . 12 hours normally sufficient Measurable Radioactivity for dynamic equilibrium to Time House House Closed occur in a home Open

Chapter 4: Health Effects of Radon and Radon Decay Products

Center for Environmental Research & Technology, Inc.

Radon and Radon Decay Product Measurement Course Chapter 4: Health Effects

Radon and Radon Decay Product Measurement Course

Chapter 4: Health Effects of Radon and Radon Decay Products

Center for Environmental Research and Technology, Inc.

Why Is Radon a Concern?

 Radon decays into radioactive particles known as radon decay Radon Decay Products products (RDPs)  These particles are Radon easily inhaled and deposited in the lungs where they can damage Radon sensitive lung tissue

Mechanism of Lung Cancer Induction

 Radon and RDPs breathed in  Radon exhaled  RDPs remain stuck to lung tissue  Po-218 and Po-214 emit alpha particles  Alpha particles strike lung cells causing physical and/or chemical damage to DNA

Alpha Particles Are Strong Enough To Pit Plastic

 Plastic chip from passive radon test (alpha track)

 Magnified only 100 times

 3 months at 4 pCi/L

Photo: Dr. J.F. Burkhart

What Happens when Radon Decay Products Are Inhaled?

. Highly radioactive OH - particles stick to lung tissue, where they can H2O irradiate sensitive cells H + . Radiation can alter the cells, increasing the potential for cancer Chromosome 6, P53 gene impacted

What Are the Odds of an Alpha Particle Hitting a Specific Part of the DNA?

 Risk is increased equally by both duration and concentration of exposure  One dart at a time for a long time, or handfuls of darts over a short time Equal weight of time and dose creates liner model of risk. One dart could be enough, hence no threshold in risk model © CERTI 2015

Radon Induced Lung Cancer Risk is Based on Probability

 Radon is a chronic health concern

 Exposure over time increases probability  Radon is not an acute hazard

 Not like short exposure to nerve gas  Probability of radon induced lung cancer a function of:

 How much you are exposed to, and

 How long you are exposed  Risk is accumulative

Excess Lung Cancer Risk Expressed in Working Level Months (WLM)

 Probability is a function of amount of exposure and time of exposure  Exposure to radon decay products is expressed in working levels (WL)  Duration of exposure is expressed in terms of months  Term comes from the mining industry where a miner worked an average of 170 hours per month

Calculating Working Level Month

WLM = WL x time of exposure (hours) 170 Hrs For example: A person living in a home at 0.02WL (4pCi/L) for one year at 75% occupancy:

WLM = 0.02 x 24 hr/day x 365 day/yr x .75 = 0.77 WLM 170 If they lived in the same house for another year, their accumulative risk would be 1.54 WLM (.77+.77)

Lifetime Risk

 For example 0.02 WL (4.0 pCi/L) for 70 years at 75% occupancy:

WLM = 0.02 x 24 hr/day x 365 day/year x 70 years x 75% = 54 WLM 170 hours/month

Increased risk in miner studies was seen as low as 40 WLM accumulative exposure (Australia)

Excess Lung Cancer Risk

1.8  No threshold 1.6 1.4  No safe level indicated 1.2  House at 200 pCi/L Linear 1 0.8  Many homes have 0.6 similar accumulative 0.4 exposures 0.2 House at 20 pCi/L 0 % excess lung cancer deaths % lung cancer excess 0 2000 4000 6000 Radon Decay Product Exposure

WLM © CERTI 2015

Scientific Basis For Radon Risk Estimates

 Studies on miners.

 Uranium miners throughout North America

 Studies on residential occupants

 On-going and as a group, confirms application of miner data to residential exposures

Iowa study (May 2000) suggests 50% increased risk of lung cancer at EPA action level of 4.0 pCi/L after 15 year exposure

 Studies on laboratory animals © CERTI 2015

Animal Studies

 Confirm carcinogenicity of radon (DOE/OER 1988a)  Evidence of respiratory tract tumors observed in rats with cumulative exposures similar to exposures in homes (NAS 1988)  Exposure to ore dusts and diesel fumes, simultaneously with radon, did not increase incidence of lung cancer above that produced by radon progeny exposures alone (DOE/OER 1988a)

Miner Data

 High incidence of lung cancer in uranium and other hard rock miners.  Human data! © CERTI 2015

Miner Studies Demonstrating Risk at Low Levels*

Miner Cohort Aver. Cum. Exp. Risk Evident At

Czech Uranium Miners 3-300 WLM 50-99 WLM

Ontario Uranium Miners 40 & 90 WLM 40-70 WLM

New Mexico Uranium Miners 110 WLM 100+ WLM

Swedish Iron Miners 80 WLM 80+ WLM

Australian Uranium Miners 7 WLM 40+ WLM

Home Exposure at 4 pCi/Lfor 70 years = Cumulative Exposure of 54 WLM

*Dr. Susan Conrath © CERTI 2015

Miners Studies Demonstrating Non-Smoker Risk*

Miner Cohort Aver. Cum. Exp. Risk Observed Colorado Plateau 720 WLM 9-12 fold increase Uranium Miners Statistically Sig. Swedish Iron Miners 80 WLM 10 fold increase Statistically Sig. Czech Clay Shale 32 WLM 10 fold increase Not Miners Statistically Sig. NM Navajo Uranium 1207 WLM 12 fold increase Miners** Statistically Sig. **Includes some smokers aver 3cig/day - RR adjusted

*Dr. Susan Conrath © CERTI 2015

Residential Radon Risk Studies

 Ecological studies (mid-1980’s)

 Review radon averages versus lung cancer rates in geographical areas

 Do not correlate individual exposures to individual cancer cases

 Not held to be valid by larger scientific community  Case-Control Studies (late 1980’s-present)

 Correlate individual exposure to lung cancer rates

 More arduous than ecological studies

Complexity of Case-Control Studies

 Cases:  Determining exposure

 Both live and deceased lung  Homes lived in cancer victims  Latency period is 5-20 yrs  Controls:  May require testing several  People in similar age groups previous residences

and demographics as cases  Predicting past radon levels from  Confounders: current measurements

 Diet, smoking history  Homes have been remodeled over the years.  Next of kin interviews  Different exposures in different parts of home

Residential Case-Control Pooling European Pooling North American Pooling

 13 Studies from 9 Countries  7 Studies from 2 countries:  Austria  New Jersey  Czech Republic  Winnipeg  Finland [nationwide]  Missouri I [non-smoking women]  Finland [south]  Missouri II [women]  France  Iowa  Germany [eastern]  Connecticut  Germany [western]  Utah-South Idaho  Italy  Total 3,622 cases and 4,966 controls  Spain  Sweden [nationwide]  Sweden [never smokers] Chinese Pooling  Sweden [Stockholm]  United Kingdom  2 Studies  Gansu  Total 7,148 cases and 14,208 controls  Shenyang

 Total 1050 cases and 1996 controls Compliments of Dr. Susan Conrath, PhD © CERTI 2015

Pooled RN Studies Courtesy of Jay Lubin, NCI EPA Action Level 4 pCi/L

Excellent agreement Validation of EPA’s use of miner data Odds Ratio = 1 Radon Concentration, pCi/L

N. America Europe China Miner Studies

Lifetime Radon Induced Lung Cancer Risk Per 1,000 People (Refer to page 12 EPA Citizens Guide*)

Lifetime Radon Exposure (pCi/L) Never Smokers Smokers

20 36 260 10 18 150 8 15 120 4762 2432 1.3 2 20

Who Has a Higher Risk Potential For Radon Induced Lung Cancer?

 Case A: Person A: 5 years at an average of 10 pCi/L Person B: 15 years at an average of 4.0 pCi/L

 Case B: Person A: 10 years at 4.0 pCi/L Person B: 4 years at 10 pCi/L

Sources of Radiation Exposure – General Public

 Radon represents the largest single source of radiation to the average citizen

How Does Radon Compare To Other Causes Of Death? 25000 Upper estimate 20000

15000 Lower estimate

10000

5000 Deaths per year (U.S.) year per Deaths

0 Drunk Radon Drowning Fires Airline Driving Crashes

Source: U.S. EPA Citizen’s Guide to Radon, 4th edition, June 2001 Radon: National Academy of Sciences 1998 data

Other: National Safety Council 1999 reports © CERTI 2015

“Radon is one of our major environmental toxicants in the United States” …(W.F. Field 2008) CANCER TYPE ESTIMATED U.S. DEATHS\YR 1. Lung and Bronchus 161,840 2. Colon and Rectum 49,960 3. Breast Cancer 40,930 4. Pancreas 34,290 5. Prostate 28,660 6. Leukemia 21,710 >> Radon Induced Lung Cancer 21,000 7. Non-Hodgkin Lymphoma 19,160 8. Liver and Bile Duct 18,410 9. Ovary 15,520 10. Esophagus 14,280 11. Urinary Bladder 14,100 12. Kidney and Renal Pelvis 13,010 13. Stomach 10,880 14. Myeloma 10,690 15. Melanoma 8,420 © CERTI 2015

Chronology – Significance Increasing

1945 First study linking radon to lung cancer (miners) 1984 Residential Exposure Headlines (Pennsylvania) 1986 EPA Issues 4 pCi/L recommendation 1990's Relocation Firms begin requiring homes < 4.0 pCi/L 1999 NAS confirms risk (BEIR VI) 2000 Appendix F of IRC Passive Radon Control Systems 2003 Science Advisory Board Reassessment confirms risk at 4.0 pCi/L 2005 Surgeon General Advisory on Radon Exposure 2005 Pooled Residential Studies Confirm Risk in Homes 2006 ASTM Standard for New Homes 2007 Canada drops radon guidance to 5.4 pCi/L 2009 World Health Org finalizes 3 yr. study - guidance: 2.7 pCi/L 2009 Health Physics Society confirms risk and supports 4 pCi/L

“Radon Is a Serious National Health Problem”

 American Lung Association  American Medical Association  Environmental Protection Agency  National Academy of Sciences  National Council on Radiation Protection and Measurement  U.S. Surgeon General  World Health Organization

EPA’s Radon Policy  All homes should be tested using radon proficient companies and testing devices  4 picocuries per liter or 0.02* WL is the “action level”  There is no absolute “safe” level  Long-term test is best measure of long-term exposure  Short-term test can be used to make decision during a home purchase and sale transaction  Smokers are at higher risk *recently suggested to be 0.016 WL © CERTI 2015

Radon Is a Gas that Causes Lung Cancer

 Breathing air with high levels of radon over long periods of time can increase the risk of lung cancer.  After smoking, radon is the second leading cause of lung cancer in the U.S.

How Does Radon Rank As A Cancer Causing Agent?  Radon is ranked as a Group A carcinogen

 Highest ranking for cancer potential

 Known to cause cancer in humans

 Tobacco smoke and tobacco products in same category  Provides basis for regulatory and liability concerns!

EPA & Surgeon General Recommend That People Not Have Exposures Above 4 pCi/L On A Long-Term Basis

Long-term exposure to radon increases the potential for Lung Cancer

EPA Policy Position on Radon

 Because Radon:

 Constitutes Substantial Risk

 Is Largely Preventable

 Is Easy to Control

 Reduction of Risk from Radon Exposure is Prudent Public Policy

Compliments of Dr. Susan Conrath, PhD © CERTI 2015

Attributable Risk for Radon

 1/3 of lung cancers from homes above EPA action level  2/3 of lung cancers from homes below action level!!!

Compliments of Bill Field © CERTI 2015

Unit Summary

 A great deal is known about health effects of radon

 Demonstrated not only in animals but also humans in working as well as residential settings.  4.0 pCi/L is a guidance – Not a “safe level”

 Most of the lung cancer cases are from exposures less than 4.0 pCi/L  The effects of radon are long-term

 Allows one to test, confirm and take deliberate action.

Chapter 5: Measurement Devices and Use

Center for Environmental Research & Technology, Inc.

Radon and Radon Decay Product Measurement Course Chapter 5: Measurement Devices and Uses

Radon and Radon Decay Product Measurement Course

Chapter 5: Measurement Devices and Use

Center for Environmental Research and Technology, Inc.

How Would You Characterize Radon Exposure in a Home?

30  Is it the highest level measured? 20  Is it an average?

Rn  If so, over what period? pCi/L 10  Where should the test be deployed?  What is the purpose of the 0 0 24 48 72 96 120 Time (Hours) measurement? This is why we have protocols! © CERTI 2015

Time Characteristics of Sampling Methods

Time Integrating Continuous  Average over time  One number Continuous  Provides Average, and

Radon  Trends Grab (sniffing)  Hourly variations  Correlate to building Time Integrating operation and entry factors 0 12 24 36 48 60 Grab (sniffing) Hours  Snap shot in time  Used for diagnostics Decisions based upon averages rather than highs and lows © CERTI 2015

Measurement Protocols and Interpretation Depend on Purpose

 Self-motivated home dweller  Citizen’s Guide  Real estate transaction  EPA & AARST Protocols  Post-mitigation measurements  Radon Mitigation Standards

Duration of Measurements

 Short-term measurement

 Any measurement from 48 hours to 90 days

 Also referred to as:

Time Sensitive Testing

Screening  Long-term measurement

 Any measurement 91 days or longer

 Also referred to as “Extended Testing”

Test Purpose Dictates Conditions

RADON POTENTIAL: OCCUPANT EXPOSURE:

 Short-term test  Long-term test

 Typically 2-5 days  Typically 91 days to 1 year

 Closed building conditions  Normal lived in conditions 12 hours prior to and all without special closed building during test conditions.

 Device deployed on lowest  Device deployed on lowest occupiable level of home. occupied level of home.

 Commonly used at time of  Commonly used outside of resale. resale, or as basis of escrow fund release. © CERTI 2015

Common Short-Term Devices

Continuous Monitors Activated Charcoal Electret Ion Chambers

 Hourly variations  2-5 Day Deployment  Overall average  2-? Deployment  Overall average  2-? Deployment  Overall average  Sent to lab for analysis  Same system can  Environmental provide long-term factors measurements

  Read by Operator Read by Operator © CERTI 2015

Common Long-term Devices 91 Days to a Year

Alpha Track Detector Electret Ion Chamber

 Suspended  Suspended or attached to interior wall  Overall average  Overall average  Read by Laboratory  Read by Operator or

Laboratory © CERTI 2015

Radon Distribution

 Radon enters from beneath foundation and travels upward

That is why short-term tests are typically deployed in lowest occupied or occupiable levels © CERTI 2015

Short-Term Tests Require Closed-House Conditions

 All exterior doors and windows closed, except for normal entry and exit  Internal-external air exchange systems off

 Total internal recycle is allowed

 Combustion or make-up air must not be closed  Permanent radon mitigation systems on, including air-air heat exchangers.

Preparing a Building For a Short-Term Test

 12 Hours Once the radon entry Rn rate into a building has RDPs been altered, time must be allowed for radon and RDP levels to stabilize. Measurable Radioactivity  Tests lasting 2 or 3 days Time House House Closed require closed house Open conditions 12 hours prior to testing.

Test Location Depends on Purpose

Lowest lived in Non-Real Estate

Suitable for Real Estate Occupancy Lowest lived in

Bedroom Bedroom Kitchen YES YES NO • Choose occupied room Garage NO • Only 1 room necessary Bedroom Closet Living Room Bathroom NO YES YES NO

Test Placement Within A Room

 Breathing Space

 Away from areas of spatial highs or lows  Where it will not be disturbed

Ceiling

Obstacle Minimum 12 inches Distance From (inches) 3 feet from Opening Wall (window or door) Floor 20 Interior 4 Ceiling* 12 inches Exterior: Interior wall 4 12 inches 20 inches Exterior wall 12 Floor Other objects 4 Minimum Distances from Features * AARST Protocol not in EPA Protocols

Measurement Strategy: Citizen’s Guide (Homeowner)

Short-Term Test Step 1 Equal to, or No No greater than 4 pCi/L? Mitigation Recommended Yes ST > 8 pCi/L ST <8 pCi/L Step 2 Follow-up Test Repeat Short-Term Long-Term Test

No Average of Results of No Yes Yes No No Mitigation 1st and 2nd results long-term test Mitigation Recommended at or above at or above Recommended 4pCi/L? 4 pCi/L? Mitigate Home

Common Real Estate Approach Continuous Monitor or Simultaneous Tests

Two Simultaneous Tests Or One CRM

YES NO Mitigation Average of Tests No Mitigation Recommended Rn/hr > 4.0 pCi/L Recommended

Device Choice Considerations

 Duration of Measurement  Accuracy

 Purpose of Measurement  Approved device?

 Other Information Desired  Ease of Use

 Tamper indicators  Send device to third party lab, or  Movement indication

 Barometric pressure, etc  Obtain results yourself

 Building parameters  Report Generation

 Room temperature  Software or cloud based programs

What is an Approved Device?

 If used to determine the need for mitigation or the success of a mitigation it is to be an “approved device”

 Listed by NRPP or NRSB and State

 Subjected to review and independent testing

 Operator has demonstrated proficiency with device.

 Currently 104 devices or device combinations listed on NRPP website.

 States typically defer to these lists.

Basics for Radon Measurement Devices Since radon decays more slowly than radon decay products do, the rate of radon decay is controlling (aka: Secular Equilibrium).

 A radon measurement is not a measurement of concentration but Rn-222 rather its activity – rate of decay. Po-218  Since radon has a longer half life than its short-lived decay products, it is the Pb-214 Bi-214 limiting or controlling variable Po-214 Pb-210 Secular Equilibrium:

The rate of decay = Decay rate of radon of radon daughters © CERTI 2015

Analogy

1 2

In a construction zone where a flagman is controlling the rate which cars pass, what is the rate that cars are getting through the construction area?

 Alt 1: Count the cars as they pass the flagman, or

 Alt 2: Count the cars a ½ mile down the road as they pass by you sitting under a shady tree.

Since the flagman is the controlling variable (longest half life), counting cars as in Alt 2 works when Secular Equilibrium has been achieved

Analogy - Which is more sensitive for measuring rainfall?

 Sensitivity relates to how much of a signal is seen or collected.

 The more signal -- the greater the accuracy can be.

 What would you do if your objective is to determine annual rainfall?

What Lab Sees Radon-222 Alpha Protons: 86  Device may look at one or more of the “signals” from the Polonium-218 Alpha decay of the short-lived radon Protons: 84 decay products. Lead-214 Beta  The more decays “seen”: Protons: 82 Gamma

 The greater the radon activity is Bismuth-214 Beta  The easier it is for the device to Protons: 83 Gamma measure.

Polonium-214 Protons: 84 Alpha

Common Short-Term Radon Measurement Devices

Commonly used devices

There are several manufacturers of these types of devices

Discussion of a particular manufacturer is not an endorsement over others

Common Charcoal Types Short-Term

 Diffusion Barrier Hung  Canister placed on table, from Ceiling shelf, desk, etc.

How Activated Charcoal Works Lab Sees: Radon-222 Rn Alpha Rn Protons: 86

Polonium-218 Alpha Protons: 84 Rn Rn RDPs Lead-214 Beta Protons: 82 Gamma

 Radon diffuses onto charcoal Bismuth-214 Beta  Radon decays to RDPs Protons: 83 Gamma  RDPs emit gamma that are measured by lab Polonium-214 Protons: 84 Alpha © CERTI 2015

How a Lab Analyzes Activated Charcoal Devices

 Device emits gamma from RDPs from radon.  Detected by scintillation detector coupled with photomultiplier tube. © CERTI 2015

What Measures the Gammas? Scintillation Detector & Photo-multiplier tube

 Scintillation material Light is struck by gamma Photo Scintillation rays. Multiplier Detector  Visible light from gamma Tube PMT detector is multiplied and changed to an Electrical Pulse Counter electrical pulse by a photomultiplier tube.

Deployment Label Remove Tape Open

Save Tape Place

Charcoal Considerations

 Humidity can reduce sensitivity

 Device weighed before and after deployment to determine correction factor

 Do not deploy in high humidity environments  Must be sent quickly to lab

 RDP Gamma signal diminishes with time reducing accuracy

 Get to lab within one week of retrieval  Can over respond when placed in drafts (increased radon migration onto charcoal)

Open Face vs. Diffusion Barrier

Rn Rn Rn Rn

Rn Rn Rn RDPs Rn RDPs Open Face Diffusion Barrier Optimal 2-3 days Optimal 3-7 days

Air movement across top of devices can cause over-response

Common Diffusion Barrier Device Short-Term

Air Chek Diffusion Barrier Activated Charcoal © CERTI 2015

Advantages of Activated Charcoal Devices

 Convenient and economical

 Can be used for 48 hour test

 Unobtrusive and silent

 Passive, does not require power

 Results can be provided as quickly as it takes to transport/ship to laboratory

Disadvantages of Activated Charcoal Devices

 Limited to short-term sampling  Must be sent to lab for analysis  Provide no indication of changes in radon during measurement. Detecting tampering by measurement alone is difficult  Must wait 3 hours after closing to analyze  Lab must correct for water intake  Not true integrating device if radon has large swings (Biased toward latter part of exposure)

Liquid Scintillation Lab Sees: Radon-222 (LS) Alpha Protons: 86

Polonium-218 Alpha Protons: 84

Lead-214 Beta Protons: 82 Gamma

 Activated charcoal inside Bismuth-214 Beta  Absorbs radon Protons: 83 Gamma  Lab immerses in scintillant solution Polonium-214  Measures “Glows” as alpha and Protons: 84 Alpha beta released © CERTI 2015

Charcoal Liquid Scintillation Description

 Plastic or glass vial containing a few grams of charcoal.

 Radon diffuses through filter in cap, is absorbed onto charcoal.

 Normal integration period is 2 to 7 days.

 Designed for short-term measurements only.

 Measures radon; results in pCi/L.

Advantages of Liquid Scintillation Devices  Same advantages as other activated charcoal devices:

 Relatively low cost

 Unobtrusive  Methodology can also be used to measure radon in water.

Disadvantages of LS Devices

 Same disadvantages as for other activated charcoal devices  Limited to short-term sampling  Biased toward latter periods of exposure  Does not provide indication of changes in radon concentrations during the measurement period

Electret Ion Chambers (EIC) Lab Sees: Radon-222 Alpha Protons: 86 Rn Filter Polonium-218 Alpha Plunger Protons: 84 Rn   Ions Lead-214 Beta RDPs  Electret Gamma + + + + Protons: 82

 Radon passes through filter, RDPs excluded Bismuth-214 Beta  Radon and its decay products release Protons: 83 Gamma ionizing radiation  Ions decrease charge on electret Polonium-214  Voltage drops proportional to radon and Protons: 84 Alpha

duration of test © CERTI 2015

Use of EICs Deploy

Select desired Measure & Record Screw into Chamber Measure & Record electret Electret Voltage Electret Voltage

Chambers have On/OFF Mechanisms that allow them to Enter Data into Program & be shipped back to your office Generate Report © CERTI 2015

Chamber/Electret Configurations

S-Chamber Variable LT-Electret Exposure

L-Chamber ST-Electret© CERTI 2015

Chamber Configurations

Configuration Typical Use for Chamber Electret Abbreviation 4 pCi/L S ST SST 2-7 days S LT SLT 3-4 months L ST LST 3-6 months L LT LLT Year

Reusing Electrets

 Electrets have initial charge of 750 volts  Can be used down to 200 volts

 Follow manufacturers' instructions  Voltage Drop is a function of:

 Level of radon in location

 Duration of measurement

 Chamber volume  Target minimum voltage drop of 20-50 volts  Allows electrets to be reused 10-25 times before replacement © CERTI 2015

Voltage Drop For Short and Long Term

Voltage Drop For Short-Term Voltage Drop For Long-Term Exposures (SST Configuration) Exposures (LST Configuration) 400 250

300 200

150 200 100 Voltage Drop Voltage 100 Drop Voltage ~ 2 V/pCi/L - day 50

0 0 0 0 20 40 60 80 100 120 140 160 180 200 pCi/L Days 100 200 pCi/L Days300 400 500 600 Select configuration that provides at least 20 volt drop © CERTI 2015

Factors to Correct For

 External ionizing radiation

 Alpha and beta cannot pass through Rn External chamber Gamma  Gamma can enter chamber External  Correct for by using background gamma Alpha tables or measuring it in your location Rn  X  Ions External  Air Density (elevation) RDPs  X + + + + Beta  The denser the air the more collisions will occur in a fixed volume chamber

 Corrected for by knowing elevation

 Corrections when above 1,200 meters (4000 feet)

Accounting for Factors That Can Influence Measurements

 Background Gamma

 Can be corrected for

 Use:  Tables in manual, or  Measure directly Tables • Gamma dosimeter  Elevation

 Enter elevation into software program Gamma dosimeter © CERTI 2015

Handling Electrets

 Voltage Loss:

 Dust on surface

 Touching surface  Destabilization

 Scratch  Clean with

 Nitrogen burst

Storing Electrets

 Storage

 In Keeper Caps

 Clean dry environment  Sort by remaining voltage

 Helps select electrets  Periodically measure stored electrets to verify stability

 Software program keeps track of this

Using the Electret Reader

 Used for all electrets and chamber combinations. Reader with calibration  Calibrate Annually certificate  Keep dry

 Desiccant in case  Orient electrets consistently

Store reader in case with Orient consistently “dry” desiccant (blue) when reading © CERTI 2015

Reference Electrets

 Verifies Reader  Check weekly  Send in with reader for annual calibration

Reference Electrets and Certificate © CERTI 2015

Use for Long-Term Measurements

OFF ON

 Slider Starts or Stops Test

 Plastic covers electret so voltage does not drop  Allows shipment or transport to lab.

Long-Term Test Wall Mount Card

• Return Date on front • Shipping materials on back Thumb-tacked to wall

Slide to Stop Test Remove mailer Record date Mail to Lab © CERTI 2015

Deploying Long-Term EICs (Tyvek Bag) Radon passes right through bag

Place device in Record Hang device on interior Tyvek Bag Information > 50 cm from ceiling > 80 cm from floor

Advantages of Electret Ion Chambers

 Used for short-term and long-term measurements.

 Electret can be re-used until voltage falls below the desired operating voltage for the device used.  Per protocols: if final voltage is < 150 volts do not use measurement  Per manufacturer: if initial voltage is < 200 volts, do not deploy  Can augment your certification by offering analytical services.

Disadvantages of Electret Ion Chambers

 Sensitive to external gamma radiation, which should be corrected for.

 Sensitive to altitude changes, which should be corrected for.

 Measure pre/post voltages at same temperature.

 Electret can be damaged by the surface being touched or contaminated, or by impact.

Continuous Radon Monitors

. Great for determining entry mechanisms . Consumer models used as post-mitigation monitors

Continuous Monitor Output

2 Radon (pCi/L)

0 Sun Mon Tue

Effect of Outdoor Air Detected by CRM

Hourly Variations Averages by Period

18 12 16 14 9.1 12 8 10 5.9 8

Radon (pCi/L) Radon 6

4 Radon pCi/L 4

2 1.7

0 0 1:00 PM 1:00 PM 3:00 PM 5:00 PM 7:00 PM 9:00 AM 1:00 AM 3:00 AM 5:00 AM 7:00 AM 9:00 PM 1:00 PM 3:00 PM 5:00 PM 7:00 PM 9:00 AM 1:00 AM 3:00 AM 5:00 AM 7:00 AM 9:00 PM 1:00 PM 3:00

11:00 AM 11:00 PM 11:00 AM 11:00 PM 11:00 AM 11:00 Total Unoccupied Occupied Radon Occupied Period EPA Guicance

• Occupied periods assumed to be: 7:30 AM to 3:30 AM • Period: April 18-20, 2007 • Hourly measurements are average for preceding hour Test © CERTI 2015

Continuous Radon Monitors Lab Sees: Radon-222 Alpha Protons: 86

Polonium-218 Alpha Protons: 84

Lead-214 Beta Protons: 82 Gamma

 Radon Diffuses in Bismuth-214 Beta  Alpha is released causes pulse Protons: 83 Gamma  Pulse recorded by machine and average radon level determined per Polonium-214 Alpha unit time. Protons: 84 © CERTI 2015

Data From Continuous Radon Monitors

 Stored in device

 Typically “blind” to occupant  Can be printed out at end of test  Some manufacturers provide:

 Ability to download data to computer

 Software programs

 Cloud based programs

Continuous Radon Monitors

+ + + + Alpha Electrical Pulse Counter - Electrical

+ Pulse Counter

Silicon Power ---- Chip Supply Pulsed ion chamber Solid state silicon detector

Zinc Sulfide Scintillation Style Glass Coating

Electronic Pulse Counter

PMT © CERTI 2015

Advantages of Continuous Radon Monitors

 Exposure duration variable - 48 hours to many months  Relatively good precision  Can track hourly variations (or more often, depending upon model)  Can download or print out readings on site  Can indicate when tampering or ventilation occurs

Practical Concerns About Continuous Radon Monitors  Ramp-up time

 In passive mode (no air pump), it takes approximately 4 hours for the monitor to respond to changes in radon levels in the room air

 Therefore, the first 4 hours of a measurement should not be used in a 48 hour exposure

 44 hours of contiguous data sufficient for “short-term”

Solid State Detector Example

Alpha Electrical Pulse Counter

Silicon Power Chip Supply

 Provides continuous measurements.  Must measure and record hourly to be used as a stand-alone device for real estate transactions.

Blind Continuous Monitors (BCRMs)

 Monitors that measure radon continuously.

 Results are stored in device, but blind to occupant and to tester.

 Data are sent via modem to central laboratory where results are interpreted and report sent to field.

 Individuals placing BCRMs may be certified as measurement service providers offering standard services.

Examples of Blind Continuous Monitors BCRMs

. Results are blind to occupant and operator . Results are sent via modem to central laboratory for analysis and interpretation

Consumer CRMs

 Not approved (as of 8/1/2015) for approved tests or final determination of need to or not to mitigate  Good post-mitigation indicators of continued system performance

Alpha Track Detectors

 Long-term Radon Measurement Device

 Integrating

 Passive  On/OFF mechanism  Can be shipped to user / lab

What Alpha Track Detector “Sees”

Rn RDPs Radon-222 Alpha Protons: 86 Filter

Rn RDPs Polonium-218 Alpha Alphas Protons: 84

Lead-214 Beta CR39 Plastic Gamma Protons: 82

Bismuth-214 Beta  Only radon passes through filter (gas) Gamma Protons: 83  RDPs excluded

 Hence, radon measurement device Polonium-214  Pit marks or tracks on plastic from alphas Alpha from Rn222, Po 218, Po 214 Protons: 84 © CERTI 2015

Analyzing ATDs

 Lab counts number of marks from alphas in a given area(s) of chip

 Number of marks proportional to:

 Amount of radon

 Duration of measurement  Must provide lab with dates of deployment

 Counting can be done by machine or by operator.

Handling Considerations

 Tracks can occur during pre-test storage or as they are shipped to lab which can add bias to measurement  Store devices in low radon environments and in original packaging from lab . Tracks can occur during  Seal devices with lab supplies storage if not properly sealed closures and send to lab within one week . Can add a positive bias to measurements

Accuracy Considerations

 Tracks from alphas can strike Skid same portion of plastic - Double hits  Alpha particles may skid horizontally across chip and be hard to see or count  This can be improved by Lab Double Hit increasing number of fields counted

Bias Considerations

 CR-39 can receive marks prior to being cut into chips

 Lab should analyze a certain number of unexposed chips (Blanks) per batch of plastic and subtract this from chips analyzed from this batch in the future  Hits from alpha during device storage or transit

 Store and ship with devices sealed

Deploying ATDs – Hanging Method

Store in foil bag Remove when Hang from ceiling Deploy 91 Days deploying

Apply foil Ship to Lab with info over ATD holes to arrive within 1 week © CERTI 2015

Deploying ATDs – Wall Card

Store in foil bag Remove when Wall card with Attach back of deploying double sided tape ATD to tape

Attach card & ATD Deploy 91 Days Remove foil from Apply foil Ship to Lab with info to interior wall back of card over ATD holes to arrive within 1 week

Advantages of Alpha Track Devices

 Relatively low cost

 Convenient

 Distributed by mail

 Unobtrusive

 Needs no external power

 Can measure long-term characteristics

 Not affected by moisture or background gamma

Disadvantages of Alpha Track Detectors

 Long measurement period necessary

 Will over-respond if filter is punctured

 Precision errors, especially at low concentrations, if small area of chip is counted

 Lab can improve precision by counting more fields

Radon & Radon Decay Product Measurement Course

Chapter 6: Advanced Measurement Devices

Center for Environmental Research & Technology, Inc.

Radon and Radon Decay Product Measurement Course Chapter 6: Advanced Radon Measurements

Radon and Radon Decay Product Measurement Course

Chapter 6: Advanced Measurement Devices

Center for Environmental Research and Technology, Inc.

Grab Sampling/Sniffing  Grab sampling

 Sample for a few seconds

 Usually analyzed at least four hours after sampling to allow for secular equilibrium Grab Radon  Sniffing

 Usually analyzed shortly after sampling, or simultaneously with sampling  no secular equilibrium achieved

 Used for diagnostic purposes Sniffing  Locating radon entry points etc. © CERTI 2015

Grab Sample Using Scintillation Cell . Room air is collected in scintillation cell, RDPs filtered out . Alphas cause cell coating to release light . “Glows” are counted Zinc Sulfide Glass Coating

Electronic Pulse Counter

PMT

Light Pulse

Scintillation Cell and Counter

Scintillation tube with white, Counter has photomultiplier tube zinc sulfide coating

Radon Grab - Single Valve Cell

 Evacuate the cell to a vacuum of 25 inches of mercury and allow air from room to enter

 Repeat evacuation and sampling five times

Practical Concerns About Grab Sampling (GS)

 Must wait until four hours after sampling to count (measuring before is “sniffing” and is less accurate)  Counting time of 10 minutes is common, but longer counting provides better precision  Alpha particles from radon and its RDPs are counted

 Used cells should be cleaned with nitrogen, aged air or fresh outside air before re-using

“Sniffing”

 Sniffing is when a grab sample is taken, but rather than waiting four hours for the collected radon to come to equilibrium with its short- lived RDPs, it is measured right after sampling Sample of supply duct compared to sample in room. Used to  Used as a diagnostic tool for determine if sub slab ductwork finding entry routes was contributing to indoor radon

Isotopes of Radon

 Isotopes are variants of the same element.

 Same number of protons, but different number of neutrons  There are 39 isotopes of radon (all have 86 protons)  The most common isotope of radon is Radon 220

Isotope Common # of Protons # Neutrons Name Radon 222 Radon 86 134 Radon 220 Thoron 86 136

Thorium-232 to Thoron (Radon 220)

 Naturally occurring like radon

 Used in lantern mantles  Breaks down to Thoron - a gas Radon 220  Released into air hl=55 sec.  Alpha emitter

 Can interfere with radon measurements  Short-half life  Paper filters retard entry into measurement device  Presents some health risk similar

to radon © CERTI 2015

Advantages of Radon Grab Sample

 Quick results

 Portable

 Can be used as a sniffer for diagnostics

 Precision quite good, if long counting times used (6 hours)

 Only accurate in identifying radon levels when sample was taken

Disadvantages of Radon Grab Sample

 Sample period is too short to use as a “short- term” measurement (i.e., less than 48 hours)  Accuracy suffers when used as a sniffer. Also, Thoron (radon-220) will be counted and must be corrected for  Cells can become so contaminated that it becomes necessary to keep them out of use for a time

Measuring Radon Decay Products Working Level Monitors

Continuous Working Level Monitors Integrating Electret Radon Progeny Sampling Units

Working Level Monitors Lab Sees: Measuring Radon Decay Products Radon-222 Alpha Protons: 86

Polonium-218 Alpha Room Air Protons: 84

Lead-214 Beta Gamma RDPs Protons: 82 Trapped Filter on Filter Sensor Counter or EIC Bismuth-214 Beta Protons: 83 Gamma  Air drawn through filter  Radon decay products adhere to filter Polonium-214 Protons: 84 Alpha  Alpha particles released and detected © CERTI 2015

Side by Side Radon and Radon Decay Products

Radon Decay Products Radon  Allows calculation of EF  Determine effect of filters, plate-out, etc.

EPERM Based ERPISU © CERTI 2015

Example - Office Building Tucson 10/21-23, 2002

12 0.06

10 Radon 0.05 8 0.04

6 0.03 EPA Guidance

4 0.02 (WL) RDPs Radon (pCi/L) Radon Radon decay products 2 0.01

0 0 2:30 5:30 8:30 2:30 5:30 8:30 11:30 14:30 17:30 20:30 23:30 11:30 14:30 17:30 20:30 23:30

AVG Radon = 6.7 pCi/L AVG RDPs = 0.007 WL AVG ER: 10.4%

Example - Large Paper Handling Facility

12 Occupied periods 0.06 10 0.05 8 0.04 6 0.03 4 0.02 RDPs (WL) Radon (pCi/L) 2 0.01 0 0 1:00 7:00 13:00 19:00 1:00 7:00 13:00 19:00 1:00

Radon WL

Example - Hotel

10 0.05 9 Radon 8 0.04 7 6 0.03 5 EPA Action Level 4 0.02

Radon (pCi/L)Radon 3 RDPs 2 0.01 1 0 0 products (WL) Radon decay 1:00 4:00 7:00 1:00 4:00 7:00 1:00 4:00 7:00 16:00 19:00 22:00 10:00 13:00 16:00 19:00 22:00 10:00 13:00 16:00 19:00 22:00 10:00

Example - House (Colorado)

10 0.05 Wood stove 9 0.045 8 Radon 0.04 7 0.035 6 0.03 5 0.025 EPA Guideline for average exposure 4 0.02 Radon (pCi/L) 3 0.015 2 0.01 1 Radon Decay Products 0.005 Radon Decay Products (WL) 0 0 3:00 5:00 7:00 9:00 1:00 3:00 1:00 5:00 7:00 9:00 11:00 13:00 15:00 17:00 19:00 21:00 23:00 13:00 15:00 17:00 17:00 19:00 21:00 23:00 11:00 Time (hour)

AVG Radon = 6.3 pCi/L AVG RDPs = 0.011 WL AVG ER: 17%

Examples of Continuous Working Level Meters

Continuous Working Level Meter

What Measures the Alphas? Scintillation Method

 Scintillation material Light Alpha is struck by alpha particles. RDPs PMT  Visible light is

Filter Scintillation counted by a Disc Electrical photomultiplier tube. Pulse Counter

What Measures the Alphas? Surface Barrier Method

 A surface barrier detector is struck by an alpha particle.  When struck, the surface barrier puts out a measurable signal proportional to the energy of the

particle. Alpha

Electrical RDPs Pulse Counter Surface Barrier

Practical Considerations for Continuous Working Level Devices

 Avoid use in dusty, smoky, and high humidity environments.

 Air flow must be well maintained and well known (0.1 L/minimum).

 If results are converted to pCi/L, the equilibrium ratio used to do so must be disclosed in report.

Advantages of Continuous Working Level Monitors

 Sampling period from 48 hours to months, if filter is maintained or replaced periodically.

 Shows variation in working levels in time.

 Can be used to detect tampering or ventilation.

 Can be used to measure individual radon and thoron decay products.

Disadvantages of Continuous Working Level Monitors

 Filter loading  Cost  Requires trained operator  Requires cognizance of operating parameters that may affect equilibrium factor and if they are constant.

Radon Progeny Integrating Sampling Units (E-RPISUs)

 Draw air through filters

 Decay products attach to filter

 Alpha particles enter electret chamber.

 Voltage change used to calculate average radon decay products for sample period

 Dual head for duplicate measurements

Electret Radon Progeny Integrating Sampling Unit

 Radon decay products collected on filter with air pump  Alpha released enters chamber

 Ionization measured by drop in electret voltage  Uses same reader as normal EIC system Diagram: Rad Elec, Inc.

Advantages & Disadvantages E-RPISUs

 Advantages  Disadvantages

 Measure both radon and radon  Provides only single decay products average for deployment period.  Duplicate measurements

 Qualitatively measure unattached vs. attached fraction

 Uses same reader as electrets

Flux Measurements

 Measuring rate of emanation from building materials.

 Concrete, granite countertops and masonry, etc.

 Emanation is typically not a large contributor.  Mitigating to below 4 pCi/L could Could my countertops be be challenging with normal active causing my radon soil depressurization techniques concerns?  Rate of emanation per unit area 2  pCi/L/m sec © CERTI 2015

Condo Above Open Air Garage

4.5 pCi/L

Open Air Garage

Test Building Material Emanation Two Concurrently Deployed CRMs Over Slab Above Garage

Radon From Concrete vs. Room Air

140

120 From Concrete 100

60 Radon (pCi/L) 40 Room Air

Scintillation Cell Method

 Radon grab samples taken of air passing through bucket  Bucket over material of Slope of line/area concern sampled  Results plotted

CRM in a Bucket

Radon in Water

Sampling for Radon in Water

 Minimize the loss of radon during sample collection

 Get a representative sample of the well water

 Sample cold water tap

 Allow water to run for a sufficient period of time to clear out the holding tank

 Minimize contact of water with air

Water Sampling Direct Syringe Method

. Kit typically has two vials  Contain mineral oil  Measured by liquid scintillation . Water samples from same source are placed into each vial

Taking the Samples

 Let cold water run long enough to clear holding tank  Connect hose with funnel to tap  Allow water to gently overflow funnel  Extract two 10 cc Capture water before it samples from beneath reaches surface the water level

Place Water Sample in Each Vial

 Put tip of syringe below mineral oil and gently inject it  Radon moves from water to mineral oil, where it readily dissolves and is held until analysis

Check Samples and Mail to Lab

 Close vial tightly  Complete paperwork, with date and time collected  Send to lab for analysis as soon as possible  Lab uses liquid scintillation to measure  &  from Rn and RDPs It is OK to have an air space with this method.

What Does the Lab See?

 The radiation from the decay of radon strikes fluorescing chemicals in the mineral oil  Emitted light is detected and correlated to radon concentration

Direct Water Sample When You Do Not Have Test Kit

 Attach tygon tubing to faucet  Run water slowly

 Minimize bubbles or turbulence  Allow water to overflow into large beaker or glass bowl  Simply submerge both bottle and cap into water supply and cap under water

Taking Samples (continued)

 Place bottle and cap under water  Place tube 2/3 way into bottle  Displace 3 or more volumes of water in bottle

Taking Samples (continued)

 Cap bottle under water  Collect two samples from each well

Check for Bubbles

 Invert bottle Bubble  Resample if bubble seen

 Pour out entire sample before refilling

 Small bubbles coming Good from dissolved oxygen cannot be avoided

Label Each Bottle

 Include location  Note date of sampling  Record time of sampling

 Hour and minute

 AM or PM

Pack and Send to Lab

 Close vial tightly  Complete paperwork including date and time collected  Send to lab for analysis as soon as possible  Lab takes its own set of 10 cc samples  Most radon in water labs use liquid scintillation

Things That Can Affect Accuracy

 Allowing radon to leave the water before capturing sample

 Sampling hot water, or sampling surface of water  Waiting too long to send it to the lab

 Lab back-calculates radon in water using lapsed time between sampling and measurement, utilizing half life correction factors  Direct samples

 Letting air get in your vial

 Air will come out of solution as water warms to room temperature

Interpreting Measurement Results of Radon in Water

 Radon in water concentrations vary  The exact contribution to air is a function of amount and type of water usage  Soil gas radon reduction generally reduces indoor radon levels more significantly than treatment of radon in water  Always recommend a radon in air test before proceeding to water remediation techniques

Radon Reduction in Water

 Technology not as well developed as that for reducing radon from soil  Requires expertise in:

 Water quality

 Radiation protection

 Radon mitigation  Contact experts/State radon contact

Radon & Radon Decay Product Measurement Course

Chapter 7: Quality Assurance and Quality Control

Center for Environmental Research & Technology, Inc.

Radon and Radon Decay Product Measurement Course Chapter 7: Quality Assurance and Quality Control

Radon and Radon Decay Product Measurement Course

Chapter 7: Quality Assurance (QA) and Quality Control (QC)

Center for Environmental Research and Technology, Inc.

Quality Control (QC)

Measures taken to increase the confidence in results. Quality control includes:

 Duplicates  Background Checks  Field Blanks  Source Checks  Spikes  Documentation  Calibration

Quality Assurance (QA)

Measures taken to assure that quality controls are being done correctly and in a timely manner.

 Keeping records  Assigning responsibilities  Having guidelines in place to automatically catch irregularities (control charts)  Inspecting procedures on a regular basis

Who Needs QA/QC Plans?

 Everyone who does radon testing  Measurement Providers offering standard services Individuals placing devices in homes analyzed by a certified lab (e.g.; activated charcoal, EICs, blind continuous monitors).  Measurement Providers offering standard and analytical services Individuals placing devices that they read on behalf of the client.  Certified Analytical Laboratories Organizations or individuals analyzing devices on behalf of radon measurement service providers or directly for the public.

Concept of Precision and Bias

 Good precision is like Good Precision Good Precision Good Bias Poor Bias having a good “group” of shots. That is, you do everything very “precisely” each time.  Good “bias” is when the average of group is close to Poor Precision and Poor Bias the bull’s-eye.

Precision (Close Grouping)

 Precision is how close simultaneously measured results are grouped together.

 Indicated by the difference of results from two simultaneously placed devices (duplicates).

Duplicates Two Simultaneous Measurements  Placed 4 inches apart and identically exposed.  10% of locations measured, 50/month maximum.  Measurement Providers offering standard services  Measurement Providers offering standard and analytical services.  CRM users to do this if they have two or more devices of the same type (See section on QA requirements of CRMs)  Certified Analytical Laboratories

Duplicate Use and Interpretation

 Calculating the Relative Percent Difference (RPD) provides a measure of precision:

Average = Result 1 + Result 2 2

RPD = (Result 1 - Result 2) x 100 Average of both results

Sample Relative Percent Difference (RPD) Calculation

 Two simultaneous long-term test devices exposed for the same 97 day period are reported by lab to be 4.1 pCi/L and 4.6 pCi/L. What is the RPD?

 Average = (4.1 + 4.6) / 2 = 4.4 pCi/L

 Difference = 4.6 - 4.1 = 0.5 pCi/L, therefore;

 RPD = 0.5 x 100 = 11.3% 4.4

Sample Control Chart for Duplicates

Control Chart for ACME Labs

 Plot RPDs versus 16 serial numbers 14 4/26/2015 and/or dates 12 2/1/2015 10 duplicates set. 8 6 3/15/2015 4 2 0 Relative PercentDdifference

Control Charts Are Used to Track Duplicate Results - See ‘93 Protocols

Duplicates  4 pCi/L Duplicates < 4 pCi/L Control Limit Control Limit 36% 67% 1% 1% RPD Warning Level Warning Level 28% 50% 5% 5% “In Control” Level “In Control” Level 14% 25% Expected Expected Dates: 4/28/97 5/14/97 5/17/97 5/22/97 6/05/97 6/15/97 7/10/97 7/29/97 8/03/97 4/30/97 5/12/97 5/15/97 5/20/97 6/08/97 6/14/97 7/13/97 7/22/97 8/01/97 © CERTI 2015

Bias (How Far Off the Bull’s-eye?)

 Bias is how far the average of simultaneous results are off from the “target” value.

 Indicated by measuring unexposed devices (field blanks).

Field Blank Measurements: Devices Not Exposed But Measured

 Field blanks measure bias.  5% of locations measured, 25/month maximum.  Measurement Providers offering standard services  Measurement Providers offering standard and analytical services (except CRMs-see QA section on CRMs)  Certified Analytical Laboratories Residential  May uncover problems associated with improperly storing, handling, and shipping.  Blank results should be close to 0 pCi/L. © CERTI 2015

Sample Control Chart for Field Blanks

Blank Control Chart for ACME Labs  Plot results of blanks versus 0.6 4/22/2015 serial numbers and/or dates 0.5 1/20/2015 field blanks were set 3/14/2015 0.4  Should be at or below lower 0.3 level of detection (LLD) for 0.2 0.1 device 0 -0.1 5/11/2015 Results Reported (pCi/L) -0.2

Blind Spiking

 Exposure of devices in certified chamber of known radon

 Analyzed by lab as regular sample (blind)

Spiked Samples: Exposure of Device To Known Radon Environment

 Used to measure accuracy  3% of measurements, minimum 3 per year, maximum 6 per month  Measurement Providers offering standard services  Measurement Providers offering standard and analytical services (except CRMs see QA section on CRMs)  Certified Analytical Laboratories

Spiked Samples Are Used to Determine Accuracy

 Approved chamber must be used  For a single measurement calculation:

Value reported by lab - Chamber value x 100 Chamber value

Example: If the spike is exposed to 6.0 pCi/L in a chamber and you or your lab report a result of 7.0 pCi/L, then the accuracy is:

Sample Control Chart for Spikes

30%  Plot results of spikes versus 20% serial numbers and/or dates 6/1/2015 8/13/2015 spikes were exposed 10%  Investigate significant deviation from known 0% concentration

-10% 9/16/2015 Accuracy ofSpikes % -20%

-30%

Documentation Requirements

 Dates and times of measurements  Conditions of test  Location of test (sketch)  Other relevant information (building, heating, etc.)  Detector description and information (ID number)

Quality Control Measures for Continuous Monitors

 Duplicates, when you own more than one of the same device  Annual calibrations

 Include background check  Device exposed to nitrogen or aged air (0 radon)  Routine instrument performance test

 Regular checks of instrument against known source  If source not available, side-by-side measurements to be made with another certified device at least every 10th measurement - including blind continuous monitors.

 Check air flow, batteries, lights, and other indicators

Analytical Devices to be Calibrated Each Year

 Device sent to chamber

 Manufacturer

 Other chamber

 Device exposed to known environment and calibration factor adjusted Femto-Tech Calibration Chamber

Performance Tests

 For those that analyze devices themselves  “Proof” of ability to measure radon or radon decay products  Required by national certification programs and many states Bowser-Morner

Additional Requirements for Offering Analytical Services

 If you want to analyze devices on behalf of your clients (offering standard and analytical services) or offer Laboratory services, you must:

 Submit device(s) to an approved chamber for performance testing (similar to spiking)

 Must be within 25% of chamber value

 Includes devices such as Electret systems (if you measure voltages) and continuous radon monitors

QC for a Residential Measurement Professional Deploying Passive Devices Analyzed by Others e.g.; AC, EIC, AT, LS

 The company arranges for spiked samples to be sent to a chamber for exposure (3%)

 The company places 5% field blanks and 10% duplicates (simultaneous real estate tests do count as duplicates)

QC for a Residential Measurement Professional Deploying Continuous Monitors

 Pass performance test  Annual calibration of all CRMs used  Annual background checks of all CRMs used  Semi-annual cross-checks of all CRMs used with recently calibrated instrument  Intercomparison of all CRMs used with another approved device every tenth measurement (if check source not available)

QC for a Residential Measurement Professional Deploying Blind Continuous Monitors

 Annual calibration of all CRMs used  Annual background checks of all CRMs used  Semi-annual cross-checks of all CRMs used with recently calibrated instrument  Intercomparison of all CRMs used with another approved device every tenth measurement (if check source not available)

QA/QC Plans Are Required

 Certification boards require you to develop a QA/QC plan

 Not required to submit them

 Some states require submittal of QA/QC plans

 Many manufacturers have simplified QA/QC plans

Radon & Radon Decay Product Measurement Course

Chapter 8: Interpreting Measurements

Center for Environmental Research & Technology, Inc.

Radon and Radon Decay Product Measurement Course Chapter 8: Interpreting Measurements

Radon and Radon Decay Product Measurement Course

Chapter 8: Interpreting Measurements

Center for Environmental Research and Technology, Inc.

Measurements as Reported by a Laboratory or Analytical Service Provider

Standard Deviation

 Because radiation is not released at a fixed interval, any measurement made over a finite time period will have an inherent error (longer measurement periods reduce error).  This inherent error can be theoretically calculated. It depends upon the total counted radiation and the background radiation.  This theoretical error is reported as a standard deviation.  Example: 4.0 pCi/L + 0.5 pCi/L

One vs. Two Standard Deviations

Type Confidence Result is within Interval One Standard Deviation 68% Two Standard Deviations 95%

Example: Lab reports 4.0 pCi/L + 0.5

 One DS: 68% confidence actual measurement is between 3.5 and 4.5

 Two SD: 95% confidence actual result is between 3.5 and 4.0

Standard Deviation (cont.d)

 Protocols do not dictate how standard deviation is reported.

 Check with laboratory to find out if the lab reports radon results using one or two standard deviations.

 The Standard deviation is not used in precision or relative percent difference calculations.

 The standard deviation indicates to a radon professional the confidence the lab has in its reported result.

Significant Figures

 Radon:

 Report to no more than one decimal place

 Examples:  3.1 pCi/L is ok  3.11 pCi/L is too many decimal places  Radon Decay Products

 Report to no more than three decimal places

 Examples:  0.033 WL is ok  0.0335 WL is too many decimal places

Citizen’s Guide to Testing Methods For the Self-Motivated Homeowner

 Single device  Initial short-term test  Closed house conditions  Lowest lived-in level of house  Follow-up test if initial short- term test is 4.0 pCi/L or above

Measurement Strategy: Citizen’s Guide (Homeowner) Short-Term Test Step 1 Equal to, or No greater than 4 pCi/L? No Mitigation Yes ST > 8 pCi/L ST <8 pCi/L Step 2 Follow-up Test Repeat Short-Term Long-Term Test

No Average of Results of No Yes Yes No No Mitigation 1st and 2nd results long-term test Mitigation Recommended at or above at or above Recommended 4pCi/L? 4 pCi/L? Mitigate Home

Follow-Up Measurements

 In same location as the initial test.

 Closed house conditions if follow-up test is short- term (i.e., if initial result is > 8 pCi/L).

 Normal lived-in conditions if follow-up test is a long-term test (i.e., if initial test was between 4 and 8 pCi/L).

 If results desired more quickly, the follow-up test can be a short-term test regardless of initial result.

Interpreting Results Citizen’s Guide

 If the initial measurement result is less than 4.0 pCi/L, follow-up measurements are probably not necessary.

 Homeowner may want to test again sometime in the future.

 If living patterns change and a lower level becomes occupied, lower level should be tested.

Interpreting Results Citizen’s Guide (continued…)

 If average of 2 short-term tests (initial and follow- up) is 4 pCi/L or higher, EPA recommends remedial action.

 Homes tested using this protocol should never be mitigated on the basis of a single short-term test.

Interpreting Results Citizen’s Guide (continued…)

 If a follow-up test was done using a long-term test, recommend mitigation if the long-term test is 4.0 pCi/L or higher.

 Do not average long-term results with short-term results.

Testing at the Time of Real Estate Transactions

 U.S. EPA recognizes the need for quick testing results

For  Safeguards are put in Sale place to reduce errors

 Represents a large portion of market

Home Buyer’s and Seller’s Guide

 Provides practical guidance to buyers, sellers, and the real estate industry.  Tells buyers and sellers what they need to know about testing and what the test results mean.

Placement of Tests for Real Estate Transactions

 For real estate transactions, place test in lowest area “suitable for occupancy…without renovations.”

 May require interpretation in some cases

 Ultimately based on how buyer will use home

 Relocation companies may decide to test lowest level that could be used by a buyer with renovations

 May be more stringent than EPA

Real Estate Testing Option: Simultaneous Tests

Two Simultaneous Tests

YES NO Mitigation Average of Both No Mitigation Recommended Tests > 4.0 pCi/L Recommended

Evaluating Simultaneous Tests Calculating the Relative Percent Difference (RPD) provides a measure of confidence: Average of both results = Result 1 + Result 2 2

RPD = (Result 1 - Result 2) x 100 Average of both results where result 1 > result 2 to ensure a positive number

Example for Calculating RPD

 If the results of two simultaneous radon tests are 4 pCi/L and 5 pCi/L respectively. What is the RPD?

 Step 1: Obtain average (4 + 5)  2 = 4.5

 Step 2: Calculate RPD (5-4)  4.5 = 1  4.5 = .225 Expressed as a percentage = 22.5%

Interpreting Simultaneous Real Estate Tests: Both Above 4.0

 If both tests are above 4.0 pCi/L, a 36% relative percent difference is expected. Results used regardless of agreement.  Report results and their average.  Examples:

 Results of 7 pCi/L and 8 pCi/L are “OK”

 Results of 17 pCi/L and 36 pCi/L are a concern Report results and investigate error

Interpreting Simultaneous Real Estate Tests: Both Below 4.0

 If both tests are below 4.0 pCi/L, 67% relative percent difference or better is expected. Results are used regardless of RPD.  Report results and their average.  Examples:

 Results of 2 pCi/L and 3 pCi/L are “OK”

 Results of 1 pCi/L and 3.5 pCi/L are a concern Report results and investigate error

Interpreting Simultaneous Real Estate Tests: One Above and One Below 4.0 pCi/L

 Use results if the higher measurement of the two is not more than twice the lower measurement.

 Report individual readings and their average.

 Examples:

 Results of 3 pCi/L and 5 pCi/L are “OK”

 Results of 3 pCi/L and 7 pCi/L are not OK”

Report as outside of range. Re-test.

What Can Cause a Large RPD?

 Test devices  Laboratory error

 Improper storage  Record keeping (especially humidity)  Biases  Improper handling  Improper shipment  Tampering  Not packed correctly  Improper Placement  Not returned to lab promptly  House conditions

 Test devices too far apart

 Air movement over devices

 Bad record keeping

Real Estate Testing Option: Sequential Testing

Initial Short-Term Test 1

Second Short-Term Test

YES NO Mitigation Average of Both No Mitigation Recommended Tests > 4.0 pCi/L Recommended

Interpreting Results of Sequential Method for Real Estate

 No requirement that results of each of the two measurements be the same.

 Some difference is expected because of normal variation of radon (diurnal, barometric pressure, rain, etc.).

 Report each result and the average of the two.

Real Estate Testing Option: A Single Continuous Monitor

48 hour test with Continuous Monitor measures and reports in increments of 1 hour or less

Mitigation YES NO No Mitigation Average > 4.0 pCi/L Recommended Recommended

Requirements for Use of Single Continuous Monitor for Real Estate

 Single Continuous Radon (CR) or Continuous Working Monitor (CWLM) must integrate and record hourly or more frequently.  Monitors that do not record at least hourly must be used with another passive or active device using either the sequential or simultaneous method.  First four hours of test may be disregarded, but 44 contiguous hours required for average.

Continuous Monitors

Ramp-Up 10 9 8 7 6 5 4 3 Radon (pCi/L) 2 1 0 0:00 1:00 2:00 3:00 4:00 5:00 6:00 7:00 8:00 9:00 0:00 1:00 2:00 3:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00 18:00 19:00 20:00 21:00 22:00 23:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00 18:00 19:00 20:00 21:00 22:00 23:00 Hour Disregarding first four hours for passive detector allows device to come into equilibrium with conditions in room rather

Successive 2-Day, Short-Term Measurement Results in Same House

Over a three-month period, short-term real estate style tests varied from 1.9 to 6.0 pCi/L.

Average for entire period was 3.8 pCi/L

States and Territories Requiring Radon Disclosure in Real Estate Transfers •Alaska •Maine • Oregon • California • Maryland • Pennsylvania • Colorado • Michigan • Puerto Rico • Connecticut • Mississippi • Rhode Island • Delaware • Missouri • South Dakota •Florida • Montana • Texas • Hawaii •Nebraska •Utah • Illinois •New Hampshire • Virginia • Indiana • New Jersey • Washington •Iowa • North Carolina • Wisconsin • Kentucky •Ohio © CERTI 2015

Typical Seller’s Property Disclosure Form Do Are there any Yes No existing hazardous Not conditions on the Know property:

Ways to Prevent or Detect Tampering

 Detect unusual measurement swings with print-out from continuous monitor.  Determine if device is moved with help of motion detectors.  Reveal presence of people with proximity detectors.  Record barometric and weather conditions.  Detect the opening of windows by recording room temperatures.

More Ways to Detect Tampering

 Use specialty tapes on exterior doors and windows to detect their being opened.

 Place device in a position where handling would be difficult or detectable.

 Don’t use devices that provide a read-out to occupant.

 Develop and use a homeowner agreement that includes cost consequences.

Ethics

 In most states, radon measurements represent confidential information between tester and client.  Incorrect protocols should be brought to attention of client.  Homeowners and clients are not bound to perform follow-up measurements, etc., but tester is to advise and recommend follow-up to client when indicated by results.

Post-Mitigation Measurements

 Perform between 24 hrs and 30 days after mitigation.

 Perform in same location as pre-mitigation tests.

 Conduct a minimum short-term test with an approved device.

 Recommend long-term testing, and re-testing once every 2 years.

Review of AARST Protocols for Measurement of Radon in Homes

Center for Environmental Research & Technology, Inc.

Radon and Radon Decay Product Measurement Course Chapter 9: AARST Measurement Protocols

Review of AARST Protocols for the Measurement of Radon in Homes

A comparison between AARST and US EPA Protocols

Doug Kladder

Center for Environmental Research and Technology, Inc.

AARST Protocols for Radon Measurements in Homes

 Added to list of standards for NRPP certified measurement professionals in 2012

 In addition to EPA Protocols  Very similar to EPA Standards  Can be purchased from AARST http://www.aarst.org/bookstore.shtml

AARST vs. EPA Protocols

 AARST

 Provides additional definitions

 Encourages retesting even if levels are less than 4.0 pCi/L

 Covers Radon Decay Product Measurements  Not previously covered in earlier 2010 version

 Provides additional requirements for client interaction and documentation  EPA

 Everything still applies

Time-Sensitive Testing Protocols

 AKA Short-Term Tests for Real Estate Testing

 Home Buyer's and Seller's Guide to Radon  Location:

 Lowest level that could be occupied  If not lowest level HVAC system should be active

 1 per 2,000 sq ft for large areas

 Consider one in each structural area that could be occupied  Example: If house has basement, crawlspace and an adjacent slab = 3 test locations  Duration: “At least 48 hours”

 46 hours allowed for passive devices

 Passive device: a device that cannot report hourly measurements

Time-Sensitive (Short-Term) Devices for Each Location Approach

 Simultaneous Passive

 Two passive devices 4 inches apart  Sequential

 Two passive devices one right after the other 1 2  Continuous Monitor

 One monitor that measures hourly Recommendation

 If average > 4 pCi/L mitigate  If average < 4 pCi/L test in future

Device Locations

Minimum Distance From: EPA AARST Floor 20 inches SAME Window or opening to outside 36 inches SAME Exterior wall 12 inches SAME Different Other devices & objects 4 inches SAME Ceiling 12 inches No more than 8 feet from floor Do not place: • In cupboards • Near heat sources • In sumps • On appliances • In nooks • Near fireplaces • Near drafts such as ceiling fans, HVAC vents • In direct sunlight © CERTI 2015

Devices

 This protocol only addresses:

 Activated Charcoal

 Electret Ion Chambers

 Liquid Scintillation

 Continuous Radon Monitors

 Alpha Track Detectors

 Radon Decay Product Measurement Devices  Other approved devices are covered under EPA protocols

Manufacturers' Recommendations (1)

 Manufacturers’ Recommendations can be followed

 Several manufacturers have done research on enclosures or locations to protect devices or make their use more practical.

 Example: Specific devices attached to interior walls or in tyvek bag

Manufacturers' Recommendations (2)

 Devices that are not affected by humidity can be deployed in humid areas, such as:

 Continuous Radon and Radon Decay Product Monitors

 Electret Ion Chambers

 Alpha Tracks  Not recommended for activated charcoal due to high water absorption

Specific to Device and Manufacturer

Minimum Deployment Period

 Should be 48 hours  No less than 46 hours  Allows tester to have a little flexibility in retrieval  Advice:

 Stay with minimum 48 hour period to avoid conflict with other printed literature.

Continuous Monitors

 First four hours of data may be disregarded

 Allow for device to come to equilibrium

 Minimum of 44 hours of contiguous data to be obtained  After device has come into equilibrium with the house

Test multiple foundation areas X Post-Mitigation Testing X

 Same location as pre-mitig. test or lowest livable area

 24 hours to 30 days after installation  Lowest livable area over each foundation area

 Must be made over isolated crawlspace area

Short-Term Test Conditions Appliances

 Whole house fans must not be operated  Avoid excessive use of:

 Clothes dryer

 Range hoods

 Bathroom fans

 Other systems that draw air out of building

Short-Term Test Conditions - (3) HVAC Item Verb Condition Whole House Fan Must Be shut off Forced air systems Must Be set to intermittent operation  Window Air ConditionerException: must can run continuously only be if system operated designed to do so. Window fans Must Be removed or sealed shut Wood burningin fireplaces recirculation and MustmodeBe shut off solid-fuel appliances Exception: Unless they are primary source of heat Window Air Conditioner Must Operate in recirculation mode Equipment that supplies air to home Must Be deactivated Exception: Unless integral part of HVAC system or provides combustion air Attic fans (not whole house fans) May Operate as normal Air Exchangers May Operate during test if regularly maintained (If part of a mitigation system should be labeled) Incomplete construction openings Must Be closed or repaired 12 hours prior to test

Short-Term Test Conditions - (4) New Homes The following items are to be completed prior to initiating test

Construction Item to be completed prior to test All insulation Exterior doors and hardware All windows All fireplaces and dampers Heating/cooling system operational and set to “normal” conditions Ceiling coverings Interior trim and wall coverings Exterior siding, weatherproofing and caulking

Short-Term Test Conditions - (5) Severe Weather

Short-Term tests that are to be less than four days in duration should not be conducted during unusually severe storms or unusually high winds

 Implied:  Don’t start if bad storm on the way  Extend test to 4 days or more if storm occurs

Extended Test Process Compared to EPA Process Differences in Yellow Boxes or Print

Short-Term Test Test every 2 years or No after major changes

Equal to, or Equal to, or Yes If greater than 100 pCi/L No Consider Fixing greater than greater than Contact State Radon Office Or Testing in Future 4 pCi/L? 2 pCi/L? > 8 pCi/L Yes < 8 pCi/L Follow-up Test

Repeat Long-Term Short-Term Test

No Yes YesResults of No Average of Mitigate long-term test Consider Fixing Consider Fixing 1st and 2nd results Home at or above Or Testing in Future Or Testing in Future at or above 4pCi/L? 4 pCi/L?

Low Initial Results - Retest Home

 Different seasons  Home addition  Changes to HVAC  Significant changes or damage to foundation  Changes to geology (earthquakes, blasting)  Mitigation system installed or altered  A ground contact area becomes occupied that was not tested before.

Levels Less than 2.0 pCi/L

 Not technically achievable to reduce homes to outdoor levels (0.4 pCi/L)  Reduction or accurate measurement of radon levels less than 2.0 pCi/L may be difficult or impossible to achieve  Indoor radon levels “can often be reduced to about 2.0 pCi/L or below”

Short-Term Test Documentation

Item Provide? Description Radon Test in Progress Form Shall Shall be placed in conspicuous location Describes test and essential conditions of test • Closed building conditions • Non-interference • Dates EPA or comparable state documents Should Be provided to each client • Home Buyers Sellers Guide • Citizens Guide Non-Interference Agreement Shall • Seek to obtain an agreement with individual responsible for building conditions with signature by individual indicating compliance with conditions • Disclosure that non-compliance may nullify results

Short-Term Test Conditions If House not Closed for 12 Hours Before

 Measurement Professional is not responsible for inspecting for closed building conditions 12 hours prior to initiating test.  If closed building conditions have not existed before test, one of the following is required: 1. Postpone test to allow for 12 hours of closed conditions 2. Extend test duration to at least 4 days 3. If hourly measurement device is used, only use data after 12 hours of closed building has existed and run for 60 hours (60-12=48). © CERTI 2015

Qualifications & QA/QC

Item Provide? Description Individual listed by state Shall Be listed by states with certification programs • Does not prevent a person from being nationally certified (below) but is not a requirement Individual listed by national Shall Be listed by National Proficiency Program certification program • Intended for states that do not have certification programs

Quality Assurance Program Shall Have a QA Plan • Written procedures • Standard Operating Procedure • Covers all measurement devices including passive devices or devices they deploy but do not analyze

Test Report - (1) Basic Information

Item Included? Building Address Shall Testers Info: Shall • Name • Certification ID with expiration date • Contact information Test timing (beginning and ending date and time) Shall Test location (diagram, photo or written description) Shall Detector info (model and type) Shall State Radon Office Contact Info Should

Test Report - (2) Measurement Results

Item Included? Individual Results Shall • Example: two passive devices used - each result is to be provided in addition to the average Hourly measurements from continuous monitors Shall Average of results in different locations Shall NOT Average of results of collocated devices Shall • Round to 1 decimal 3.95 = 4.0 3.13 = 3.1 Quality control measures that were used during test Shall • Example: field blanks, duplicates Recommendations for Action Based upon EPA Shall • Home Buyers and Sellers Guide or Citizen’s Guide

Test Report - (3) Test Conditions

Item Included? Unusual weather conditions occurring during test Shall Observed deviations from required test conditions Shall • Including deviation from normal temperature Deviations from measurement procedures Shall If responsible party did or did not sign noninterference agreement Shall Copy of signed noninterference agreement Should Description of noninterference controls Should Condition of vents that allow outdoor air into building, such as: Shall • Combustion air • Crawl vents Presence and condition of installed ventilation system, such as: Shall • Air-to-Air heat exchanger Statement that test results may not reflect risks if condition of vents Shall or ventilation equipment are altered from state that existed during test

Test Report (4) Mitigation Status

Item Included? Statement if mitigation system was observed Shall Statement if mitigation system fan was operating Shall • Assumes that mitigation system is an ASD system • Logical to include other types if operational

Test Report - (5) Test Limitations

 Statement of general limitations of test

 Uncertainty of measurement (statistical variations)

 Seasonal variations

 Weather changes

 Potential changes to how building is operated

 Possible test interference  Recommendation for testing at least every 2 years and after major building changes (see Future Testing)

Future Testing

 Confirm low results

 Retest every two years even if initial test is low  Retest when:

 Structure of home is modified (significant)

 Mechanical system is changed (significant)  Retest during a different season or with long-term device

Record Retention

 Minimum requirement: 5 years  Recommendation: Indefinitely

Karst Geologies

 Karst: Permeable geology due to limestone solution cavities

 Radon provided to foundation can be significantly different in different seasons  No specific protocols identified in Appendix G  Confirming “low” results may be important

 Additional short-term test in different season

 Long-term test

Radon Decay Product Measurements (1)

 Conduct in conjunction with radon measurement

 Allows determination of equilibrium factor  Report both radon and radon decay product measurements

 Compare to Radon (4 pCi/L) and RDP guidances (0.020 WL)*

 No need to convert between the two measurements

Radon Decay Product Measurements (2)

 Identify conditions that may affect RDP plate-out

 Stagnant air

 High air circulation rates

 High efficiency filters

 No closer than 10 feet to televisions

 Away from ceiling fans, etc  Determine constancy of conditions when making recommendations

Additional Resources and Updates

Organization URL

AARST – To obtain printed or electronic version of standard www.AARST.org

Center for Environmental Research and Technology, Inc. www.certi.us

National Radon Proficiency Program www.nrpp.info

If you are viewing this program as part of a CERTI course be sure to check out the resource section for additional tools and resources

Center for Environmental Research and Technology, Inc.

Radon & Radon Decay Product Measurement Course

Acronyms

Center for Environmental Research & Technology, Inc.

Acronyms

Acronym Name Group AARST American Association of Radon Scientists and Technologists Organization AC Activated Charcoal Meas Devices ACH Air Changes per Hour Mitigation ASD Active Soil Depressurization Mitigation AT Alpha Track Detector Meas Devices AT Alpha Track Mitigation ATD Alpha Track Detector Meas Devices BEIR Biological Effects of Ionizing Radiation Physics Bi Bismuth Physics Bq/m3 Becquerel per cubic meter Physics BWD Block wall depressurization Mitigation CFM Cubic feet per minute Mitigation Ci Curie Physics C‐NRPP Canadian National Radon Proficiency Program Organization COV Coefficient of Variation Meas Devices CR Continuous Radon Meas Devices CRCPD Conference of Radiation Program Directors Organization CRM Continuous Radon Monitor Meas Devices CSD Crawlspace depressurization Mitigation CWLM Continuous Working Level Monitor Meas Devices dp Differential Pressure Physics EF Equilibrium Factor Physics EIC or EC Electret Ion Chamber Meas Devices EPA Environmental Protection Agency Organization ER Equilibrium Ratio Physics ERPISU Electret Radon Progeny Integrating Sampling Unit Meas Devices f Equilibrium Factor Physics GAC Granular Activated Carbon Mitigation GS Grab Sampler Meas Devices HC Health Canada Organization InH20 Inches of water column pressure Physics LLD Lower Limit of Detection Meas Devices LS Liquid Scintillation Meas Devices MSHA Mine Safety & Health Association Organization msv milli sievert Physics NRPP National Radon Proficiency Program Organization NRSB National Radon Safety Board Organization OSHA Occupational Safety and Health Organization

Center for Environmental Research & Technology, Inc. www.certi.us • 800‐513‐8332 Page 2

Acronym Name Group Pa Pascal Physics Pb Lead Physics pCi/L pCi/L Physics PFE Pressure Field Extension Mitigation Po Polonium Physics QA Quality Assurance Meas Devices QC Quality Control Meas Devices Ra Radium Physics RDP Radon Decay Product Physics RMS Radon Mitigation Standards Organization Rn Radon Physics RPD Relative Percent Difference Meas Devices SD Standard Deviation Meas Devices SI Units Scientific International units like meters instead of feet Physics SIRG State Indoor Radon Grants Organization SMD Sub‐membrane Depressurization Mitigation SSD Sub‐slab depressurization Mitigation STD Drain Tile Depressurization Mitigation sv Sievert Physics WL Working Level Physics WLM Working Level Month Physics α Alpha particle Physics β Beta Particle Physics γ Gamma Physics

Center for Environmental Research & Technology, Inc. www.certi.us • 800‐513‐8332