How-to Guide

Indoor Air Quality


Why Indoor Air Quality Matters

For many decades, the study of air pollution was largely confined to the outdoor environment. This makes sense, right? Generally speaking, problems linked with outdoor air have been much more obvious. When you try to picture large cities following the Industrial Revolution, what comes to mind? Yep, the ever-growing miasma of automobile exhaust, smokestack emissions, and smog. This problem eventually became impossible to ignore, and ultimately forced scientists and governments to take action.

Fortunately, particulate matter and other pollution have dramatically declined over the past 40 years in the US, due in large part to regulations implemented by the Clean Air Act of 1970 and its subsequent amendments. Deaths linked to air pollution fell by around 30% between 1990 and 2010.

Unfortunately, as the outdoor air in the United States and other western nations has become cleaner, our exposure to indoor pollutants has increased at the same time. Why? There are a few likely contributors.

For one thing, houses and office buildings have become more tightly sealed and insulated, in order to reduce the need for heating and cooling. This was a well-conceived adaptation to energy shortages in the 1970s, and one from which all of us continue to benefit. But a hidden consequence of this effort at energy conservation was a reduction in ventilation rates - meaning that pollutants within buildings could linger longer than ever before.

Furthermore, we are introducing more and more potential contaminants into the indoor environment in the form of personal care products, housekeeping supplies, pesticides, furnishings, and other substances. Indeed, the US Environmental Protection Agency (EPA) has estimated that concentrations of certain recognized pollutants may be 2-5 times higher than typical outdoor concentrations.

Finally, our lifestyle patterns have made the safety of indoor air more relevant now than perhaps ever in our history as a species. Research suggests that Americans, on average, spend about 90% of their time indoors (probably even more than that now). And research is starting to uncover the insidious role that indoor air quality may play in human health. Just as one example, asthma incidence has risen dramatically in Western countries, and is presently regarded as the most common chronic disease in children living in urban areas. Allergens and irritants circulating in indoor air have been linked to both the development of asthma and asthma attacks. No surprise there. But some more serious long-term effects may be less discernible, and only become evident after chronic low-grade exposure. For example, some research suggests that long-term exposure to indoor air pollutants are linked to elevated blood pressure and greater cardiovascular risk. Exposure to volatile organic compounds that emanate common household products has also been shown to be associated with increased cancer risk.

Perhaps even more remarkably, some observational and experimental evidence suggests that indoor air quality may impact the brain. For instance, chess players participating in tournaments held in buildings with poorer air quality are substantially more likely to make meaningful errors. And it is likely that the effect of air pollution on cognitive performance probably has implications beyond playing board games.

When researchers had workers spend one week in a conventional office building, and then a week in a highly ventilated building low in pollutants, the workers’ cognitive performance rose a full 100% higher. Another instructive example comes from Los Angeles area school districts. The installation of basic commercially available air filters resulted in major boosts in math and English test scores - comparable to the impact associated with cutting class sizes by a third! Could clean air make you and your family smarter, more productive, and healthier? Seems very possible.

The effect of indoor air quality is subtle, and doesn’t always produce an acute and easily recognizable impact on health and performance. But make no mistake, it matters. This guide will show you how to test indoor air quality, and support the maintenance of better air quality in your indoor spaces.

Types of Indoor Air Pollution and Some Effects

  • Radon - Radon is a radioactive gas that is formed in soil. It can get into indoor environments through cracks and openings in floors and walls that are in contact with the earth. It is the leading cause of lung cancer in non-smokers, and the second leading cause of lung cancer overall.

    You cannot see or smell radon. You can only determine your exposure through testing, and every home should be tested, especially if you are in a high risk area. Here is a link to local radon zones from the Environmental Production Agency to identify parts of the US that are potentially subjected to indoor radon levels. More on radon testing kits below under Products.
  • Secondhand and Thirdhand Smoke - Secondhand smoke refers to smoke exposure from other individuals’ tobacco products, and thirdhand smoke refers to the residual contamination that results from indoor smoking. It has been linked to cancer and respiratory illness. Children are particularly susceptible to the effects of this form of pollution - it has been linked to asthma, ear infections, and SIDS (sudden infant death syndrome).

    Prevention is simple, albeit not easy. Needless to say, if you (or someone in your household) smokes, now is as good a time as any to quit. If that isn’t an option, at least ensure that the behavior is strictly confined to the outdoors.
  • Combustion Pollutants - Combustion pollutants are gases or particles that emanate from burning materials. In houses, the primary sources of such pollutants include space heaters, wood and gas stoves, water heaters, fireplaces, and dryers. Whether these pollutants are generated from these devices depends on the type of fuel used, as well as how well the appliance has been maintained and vented.

    The main combustion pollutants to be concerned about here are carbon monoxide (CO) and nitrogen dioxide (NO2).

    CO is colorless and odorless and interferes with delivery of oxygen in the body (obviously no bueno). Carbon monoxide can induce a range of health effects, including headaches, dizziness, nausea, and death (if exposed long enough.Can release carbon dioxide and nitrogen dioxide. These gases cause headaches, dizziness, weakness, nausea, and death - as well as eye, nose, throat irritation and respiratory infections.

    Nitrogen dioxide (NO2) is a colorless gas that causes shortness of breath and respiratory symptoms. It has a nasty, acrid smell, so you’re less likely to miss it.
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