Gord Cooke, President of Building Knowledge Canada, is a Professional Engineer with 25 years experience in the residential building industry. An educator, industry consultant, and international presenter, Cooke specializes in presenting practical building science solutions in understandable terms.
Credit: John Beebe/Aurora Select
“Can you test the air in my home?”
That’s the call I get from builders who are looking for certification or validation that the homes they are building provide a healthy indoor environment. Since there is no definitive quantitative measure for air quality that would satisfy all potential occupants, I tell them that rather than spend thousands of dollars on testing, they should invest in cost-effective construction details, material, and equipment options that have proven to ensure the healthiest possible indoor air quality.
Most people tie “air quality” issues to the outside—air pollution from cars and factories or smog, haze, and ozone; however, the Environmental Protection Agency reports that a growing body of scientific evidence suggests that inside air can actually be more seriously polluted than outdoor air in even the largest and most industrialized cities.
I like to think of it this way: The air in homes originally came from outside, then we breathed in it, cooked in it, and showered in it without really doing anything substantial to improve it.
- We spend more time—as much as 90% of it—indoors all year round. That means nine out of every 10 breaths is of indoor air—much of it from our homes.
- We introduce pollutants into houses via furnishings, cleaning chemicals, and personal hygiene products. There are 4,000 to 6,000 chemicals that may be found in our houses. Plants and pets are also sources of dust, moisture, and odors.
- Our interest in better comfort, lower noise, and greater security reduces the use of windows for natural ventilation.
Compounding these ever-increasing levels of indoor air pollutants is the fact that our homes are tighter than ever as we strive to build energy-efficient structures. Still, air tightness of buildings is not the main reason for increased indoor air quality concerns; in fact, controlling air leakage is an important element of air quality control because it keeps out unwanted outdoor pollutants such as pollen and fine dust particles and allows HVAC systems to better control the flow of filtered, conditioned air.