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Home , Air pollution, Indoor air quality, Particulates

Indoor Air Quality Backgrounder: The Basics

I ndoor air quality (IAQ) is an Failure to prevent or respond promptly to increasingly important issue in schools IAQ problems can: across the nation. IAQ can directly affect • Increase potential for long- and short- the and comfort of students and term health problems for students and staff. There are many ways that school staff. occupants can help to improve air quality. EPA developed the Indoor Air • Negatively impact student attendance, Quality Tools for Schools (IAQ TfS) comfort, and performance. Program to help schools address many IAQ issues using practical and often • Reduce teacher and staff comfort and performance. low-cost measures (such as unblocking ventilation supply vents to improve • Accelerate deterioration and reduce airflow). efficiency of school facilities and Good IAQ helps to equipment. By simply reviewing this Indoor Air provide a healthy Quality Backgrounder and completing • Increase potential for school closings and productive envi- the IAQ , occupants can learn or relocation of occupants. ronment for students, how to make a significant impact on teachers, and staff IAQ and provide a healthy learning and • Strain relationships among school working environment. administration, parents, and staff. in order to assist a school in its This guidance is based on the • Create negative publicity. following principles: • Impact community trust. core mission— educating children. • Most IAQ problems can be prevented • Create liability problems. and resolved by school staff through simple, inexpensive measures. UNDERSTANDING IAQ • The cost and effort needed to prevent PROBLEMS AND most IAQ problems is significantly To understand IAQ problems and less than the cost and effort required solutions, it is important to know what to resolve problems after they factors affect IAQ. These include: develop. • Sources of indoor air . WHY IAQ IS IMPORTANT TO • Heating, ventilation, and air YOUR SCHOOL conditioning (HVAC) systems. Most people are aware that outdoor • occupants. air can impact their health, but indoor can also have • pathways. significant, harmful effects. EPA studies of exposure to air SOURCES OF INDOOR AIR pollutants indicate that indoor levels of POLLUTANTS pollutants may be two to five times— Indoor air contaminants can originate and occasionally more than 100 times— within the building or be drawn in from higher than outdoor levels. EPA and its outdoors. Air pollutants consist of Science Advisory Board consistently numerous , fibers, , rank indoor air pollution among the top , and . It is important to five risks to the control air pollutant sources (see the table public. on the next page), or IAQ problems can This is especially important to schools, arise—even if the HVAC system is as children may be more susceptible to properly operating. air pollutants.

1 of 5 A complicating factor is that indoor air Not all HVAC systems accomplish all of pollutant concentration levels can vary by: these functions. Some rely only on natural ventilation. Others lack • Time (for example, weekly, during floor mechanical cooling equipment, and many stripping); and function with little or no control. • Location (within a school or even The two most common HVAC designs in within a single classroom). schools are unit ventilators and central air- HVAC System Design and handling systems. Both can perform the Operation same HVAC functions, but a unit ventilator serves a single room while a Properly designed HVAC equipment in a central air-handling unit serves multiple school helps to: rooms. • Control temperature and humidity to The diagrams on page 5 of this Indoor Air provide . Quality Backgrounder show how three • Distribute adequate amounts of outdoor typical HVAC designs circulate air air to meet ventilation needs of school through classrooms. As shown in the occupants. diagrams, it is important that all rooms have both an air supply and exhaust. • Isolate and remove and pollutants through pressure control, filtration, and exhaust fans.

TYPICAL SOURCES OF INDOOR AIR POLLUTANTS

Outdoor Sources Building Equipment Components and Other Indoor Furnishings Sources Polluted Outdoor Air HVAC Equipment • , , fungal • Microbiological growth Components • Science spores in drip pans, ductwork, • Microbiological growth supplies • Industrial emissions coils, and on or in soiled or - • Vocational art supplies • Vehicle emissions • Improper venting of damaged materials • Copy/print areas products Nearby Sources • Dry traps that allow the • prep areas • Dust or debris in passage of sewer • Loading docks ductwork • Smoking lounges • Materials containing • Cleaning materials • Odors from dumpsters Other Equipment volatile organic • Emissions from trash • Unsanitary debris or • Emissions from office compounds, inorganic building exhausts near equipment (volatile compounds, or damaged • outdoor air intakes organic compounds, • Odors and volatile Underground Sources ) • Materials that produce organic compounds • • Emissions from shop, (dust) from , chalk, • Pesticides lab, and cleaning Furnishings adhesives • Leakage from equipment • Emissions from new • Occupants with underground storage furnishings and communicable diseases tanks floorings • Dry-erase markers and • Microbiological growth similar pens on or in soiled or water- • Insects and other pests damaged furnishings • Personal care products

2 of 5 Building Occupants SIX BASIC CONTROL The effects of IAQ problems on school STRATEGIES occupants—including staff, students, and There are six basic control methods that others—are often non-specific symptoms can lower concentrations of indoor air rather than clearly-defined illnesses. pollutants. Specific applications of these Symptoms commonly attributed to IAQ basic control strategies may be noted in problems include: the attached (s). • Headache, fatigue, and . 1. Source Management - Management of pollutant sources includes: • Sinus congestion, , and sneezing. • Source removal - Eliminating • Eye, nose, , and skin irritation. pollutant sources or not allowing them • Dizziness and nausea. to enter the school. Examples include not allowing buses to idle, not placing These symptoms could be caused by air in rooms with HVAC quality deficiencies, but may also be equipment, and replacing moldy linked to other factors—poor lighting, materials. stress, noise, and more. Due to varying sensitivities among school occupants, IAQ • Source substitution - Replacing problems may affect a group of people or pollutant sources. Examples include just one individual. In addition, IAQ selecting less- or non-toxic art problems may affect people in different materials or interior . ways. Individuals that may be particularly • Source encapsulation - Placing a susceptible to effects of indoor around the source so that it contaminants include, but are not limited releases fewer pollutants into the to, people with: indoor air. Examples include covering • , , or chemical pressed cabinetry with sealed or sensitivities. laminated surfaces or using sheeting to contain contaminants when • Respiratory diseases. renovating. • Suppressed immune systems (due to 2. Local Exhaust - Removing point sources radiation, chemotherapy, or disease). of indoor pollutants (through exhausting • Contact lenses. fume hoods and local exhaust fans to the outside) before they disperse. Examples Pollutant Pathways and include exhaust systems for restrooms and Driving Forces kitchens, science labs, storage rooms, Airflow patterns in buildings are printing and duplicating rooms, and determined by the combined forces of vocational/industrial areas (such as welding mechanical ventilation systems, human booths and firing kilns). activity, and natural effects. Air pressure 3. Ventilation - Lowering pollutant differences created by these forces move concentrations by using cleaner (outdoor) airborne pollutants from areas of higher air to dilute polluted (indoor) air. Local pressure to areas of lower pressure building codes likely specify the quantity through any available openings in building (and sometimes quality) of outdoor air that walls, ceilings, floors, doors, windows, should be continuously supplied in your and HVAC systems. For instance, as long school, as do voluntary standards set by the as the opening to an inflated balloon is American Society of Heating, kept shut, no air will flow. When opened, Regrigerating, and Air-Conditioning however, air will move from the inside Engineers (ASHRAE). Temporarily (area of higher pressure) to the outside increasing ventilation coupled with proper (area of lower pressure). use of the while painting or Even if the opening is small, air will move applying pesticides, for example, can be until the inside pressure is equal to the useful in diluting the concentration of outside pressure. noxious fumes in the air.

3 of 5 4. Exposure Control - Adjusting the time and • Symptoms are widespread within a IAQ Checklists location of pollutant exposure. An example class or school. Available of time control is scheduling floor stripping • Symptoms disappear when the and waxing (with the ventilation system • Teacher’s students or staff leave the school functioning) for Friday after school. This building for a day or for extended • Administrative Staff allows products to off-gas over the weekend periods of time. while the school is unoccupied. Location • School Official’s control involves moving the pollutant source • Onset is sudden after some change • Health Officer’s away from occupants or even relocating at school (such as painting or susceptible occupants. application). • Ventilation

5. Air Cleaning - Filtering particles and • Reactions occur indoors but not • Building Maintenance outdoors. gaseous contaminants as air passes through • Food Service ventilation equipment. In most cases this • Symptoms have been identified by type of system should be engineered on a a doctor as being IAQ-related. • case-by-case basis. It is not safe to assume that a lack of • Renovation and Repairs 6. Education - Teaching and training school symptoms means that the IAQ in your occupants about IAQ issues. People in the school is acceptable. Symptoms of • Integrated Pest school can reduce their exposure to many long-term health effects (such as Management pollutants by understanding basic due to radon) often do not • Walkthrough information about their environment and become evident for many years. knowing how to prevent, remove, or control pollutants. IF YOU THINK YOU HAVE AN IAQ PROBLEM Some solutions, such as major ventilation changes, may not be practical to implement If you have a potential IAQ problem due to lack of or the need for long in your school or area that requires periods of non-occupancy to ensure the a simple or action, correct safety of the occupants. Use temporary the problem. If the problem cannot measures to ensure good IAQ in the be easily corrected or if the complaint meantime. Other solutions, such as anti- seems to indicate a potentially severe idling programs, offer low-cost options that IAQ problem, contact the IAQ can be easily and quickly implemented. Coordinator immediately. The IAQ Coordinator will investigate the YOUR ROLE IN THE IAQ problem further, either using in-house TEAM resources or by calling in help from outside the school. As a school occupant, your activities and decisions have an impact on the quality of COMMUNICATION the school’s indoor air. You can participate by completing the appropriate checklist Because of the health risks involved, and by continuing to apply these principles parents, the community, and media on a daily basis. Your school’s IAQ may react strongly to reports of poor Coordinator serves as a focal point for in your school. It is collecting IAQ information and handling recommended that you follow your IAQ concerns. school’s IAQ communications guidelines. This typically involves HOW TO KNOW IF YOU HAVE referring all questions and inquiries to one central source—the IAQ AN IAQ PROBLEM Coordinator. This is the best way to Diagnosing IAQ-related symptoms avoid incomplete, incorrect, or can be tricky, especially because acute conflicting information regarding the (short-term) symptoms are similar to those quality of the air in your school and from colds, allergies, fatigue, any actions necessary to improve IAQ. or the flu. There are clues, however, For more information, refer to the IAQ that can help link symptoms to IAQ TfS Communications Guide, posted on problems: EPA’s Web site: www.epa.gov/iaq/schools

4 of 5 Central Exhaust Optional Location for Unit Ventilator

Exhaust Air Through... Air Supply through a Central Room or Vent Vent Unit Ventilator

Supply Air

Unit Ventilator

Return Air

Outdoor Air Supply

Outdoor Exhaust Air Air Supply Central Air Handling Unit (may be located indoors)

Return Air Supply in a Central or Supply Plenum Air Handling System Duct Return Supply Air Air

Central Exhaust Fan

Outside Air Air Supply in an is Supplied Exhaust through Exhaust-only System Air Loose Windows and other Openings

Baseboard or Similar Form of Heat

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