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De-Mystifying Indoor Air Quality What Causes IAQ Problems and What Can You Do About It?

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De-Mystifying Indoor Air Quality What Causes IAQ Problems and What Can You Do About It? INDOOR AIR QUALITY | building science De-Mystifying Indoor Air Quality What causes IAQ problems and what can you do about it? an you test the air in my concerns; in fact, controlling air leakage is an impor- home?” tant element of air quality control because it keeps “ That’s the call I get from out unwanted outdoor pollutants such as pollen and builders who are looking for fine dust particles and allows HVAC systems to certification or validation that better control the flow of filtered, conditioned air. the homes they are building provide a healthy indoor environment. Since there SIMPLE STRATEGIES isC no definitive quantitative measure for air quality Fortunately there are simple things that we can do Gord Cooke that would satisfy all potential occupants, I tell to ensure the healthiest possible air in homes. Most Gord Cooke, President of Building them that rather than spend thousands of dollars of these fall into one of four important strategies: Knowledge Canada, is a Professional on testing, they should invest in cost-effective con- 1. Remove Pollutant Sources. Engineer with 25 years experience struction details, material, and equipment options ■ Manage water to avoid mold and dampness. in the residential building industry. that have proven to ensure the healthiest possible Plan drainage, flashing, grading, capillary breaks, An educator, industry consultant, indoor air quality. and air sealing to avoid water intrusion. and international presenter, Cooke Most people tie “air quality” issues to the ■ Use low- or zero-VOC paints and finishes and specializes in presenting practical outside—air pollution from cars and factories or choose hard-surface, prefinished flooring. building science solutions in smog, haze, and ozone; however, the Environmental ■ Specify solid wood products or, if using understandable terms. Protection Agency reports that a growing body of engineered wood products such as OSB, MDF, and scientific evidence suggests that inside air can actu- particleboard, specify products that are tested to ally be more seriously polluted than outdoor air in show they have low-VOC emissions. even the largest and most industrialized cities. 2. Seal Out Pollutants. I like to think of it this way: The air in homes ■ Ensure a very thorough air seal between a originally came from outside, then we breathed in house and an attached garage. it, cooked in it, and showered in it without really ■ Seal the edges of exposed particleboard cabin- doing anything substantial to improve it. etry or trim with a low-VOC acrylic sealer. Also consider: ■ Create an “oasis” for occupants who suffer ■ We spend more time—as much as 90% of it— from respiratory problems, asthma, or allergies. indoors all year round. That means nine out of every 10 This might entail creating a very “clean” bedroom breaths is of indoor air—much of it from our homes. with its own fresh, filtered air supply. ■ We introduce pollutants into houses via furnish- 3. Ventilate the Space. All houses need more fresh ings, cleaning chemicals, and personal hygiene prod- air. While encouraging homeowners to open windows ucts. There are 4,000 to 6,000 chemicals that may be regularly is helpful, all projects should include provi- found in our houses. Plants and pets are also sources sions for mechanical ventilation. This could be as of dust, moisture, and odors. simple as installing good, quiet, efficient bath fans or ■ Our interest in better comfort, lower noise, a fresh intake into the main air handler return that and greater security reduces the use of windows for are controlled by a timer to ensure extended hours of natural ventilation. operation each day. The advanced solution is heat- and Compounding these ever-increasing levels of energy-recovery ventilation technology. These devices indoor air pollutants is the fact that our homes include one fan that exhausts stale air and another fan are tighter than ever as we strive to build energy- that delivers fresh air to a home. The waste energy efficient structures. Still, air tightness of buildings is from the exhaust air is used to preheat the incoming PHOTO: JOHN BEEBE/AURORA SELECT not the main reason for increased indoor air quality air in the winter and precool it in the summer. JANUARY | FEBRUARY 2010 ecohomemagazine.com 13 building science | INDOOR AIR QUALITY A FIGURE 1: FOCUS ON DETAILS A Control moisture to prevent mold. F B Isolate garage from living areas. C Install fresh air ventilation and filtration. D Keep water away from foundation. E Use low-VOC building materials. E F Use low-VOC paints and finishes. B ■ Thorough, consistent water management details to ensure buildings don’t get wet and that if they do get wet they are able to dry within 48 hours to avoid mold and rot. ■ Properly sized HVAC systems to ensure con- D sistent temperatures and humidity levels. ■ Effective, efficient ventilation systems that bring in just the right amount of fresh, filtered air. ■ Control of unwanted air leakage from outside to reduce dust and pollen entry. C ■ Effective insulation and better, warmer win- dows to avoid condensation on surfaces. ■ Air handlers with filters with better filtration effectiveness—MERV 8 or better. EDUCATE YOUR CUSTOMERS 4. Filter the Air. Choose better filters for the To ensure your IAQ steps are effective, it’s vital to central air handler. The new MERV (Minimum teach residents simple strategies for maintaining Efficiency Reporting Value) filter effectiveness healthy indoor air. Here are a few best practices to measurement scale under ASHRAE Standard 52.2 pass on: offers ratings from 1 to 20, with 1 being a simple, ■ Never allow smoking indoors. fiberglass furnace filter and 20 being a HEPA filter. ■ Choose hard-surface flooring; clean floors A good pleated filter with a MERV rating between thoroughly at least once a week. 8 and 12 is very helpful in removing fine dust from ■ Limit the use of chemical cleaners, and choose inside air. unscented cleaning and personal hygiene products. These four steps are listed in order of effective- ■ Keep pets and plants out of sleeping areas. ness. Start with removal strategies first before ■ Manage indoor humidity and odors by using Resources spending too much time or effort on filtration. bathroom and kitchen fans regularly. The strategies are recognized and rewarded by By implementing these details and specifications, For more information, certification programs such as LEED for Homes, the as well as passing along a few consumer guidelines, check out these Web sites: ANSI National Green Building Standard, and the building professionals can assure clients they are pro- Energy & Environmental new EPA Indoor airPLUS program. viding the potential for a healthy indoor environment. Building Alliance: Specification checklists from programs such as As hinted in the introduction, this does not mean www.eeba.org these provide a great starting point for building you can guarantee air quality or prevent all indoor air EPA: professionals wishing to ensure their clients are quality problems. I like to remind my clients that I am www.epa.gov/indoorairplus provided with the healthiest possible air. At a mini- a housing professional and not a health professional. LEED for Homes: mum, appropriate details always include: Lifestyle choices and the personal health of occupants www.usgbc.org ■ Direct- or power-vented combustion appliances is beyond our control but to the extent that indoor to ensure the safe, effective venting of combustion air is an important input to our bodies, we can help NAHB: www.nahbgreen.org products directly outside. ensure that air is as clean as possible. WHITVER HARRY ILLUSTRATION: 14 ecohomemagazine.com JANUARY | FEBRUARY 2010.
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