Indoor air quality testing may be done to determine levels of allergens, irritants, or contaminants indoors, and also generally involves determining whether the temperature and humidity are within the “comfort zone.” The concentrations of particles in the air are often included. The concentration of carbon dioxide may also be measured. Carbon dioxide is always present outdoors, but may be present in greater concentrations indoors as people work and live in closed spaces, inhaling oxygen and exhaling carbon dioxide. But elevated levels of this gas indoors generally indicate inadequate building ventilation, and cause people to feel sleepy and describe the air as “stuffy.” A lack of fresh air indoors also results in higher concentrations of other chemicals that can be found in buildings, including formaldehyde, solvents, or even carbon monoxide. So indoor air quality testing may include measuring levels of these gases and chemicals, too.

People often call me and ask me to test because they want me to tell them that the “air quality is OK.” It’s difficult to give a simple answer, because conditions in an indoor environment change over time, you can’t test for everything, and people’s susceptibilities to various substances can differ enormously. So any indoor air quality consultant must ask building occupants questions about where and under what conditions they suffer health symptoms, make some decisions about where and what to test for based on his or her experience in the field, and be sure to focus the testing on what seems most relevant, in order to control costs. Indoor air quality testing can be very expensive and unfortunately, not always altogether that helpful.

I’m a chemist, so I know something about the chemicals that can be found indoors. Unfortunately, the testing equipment that some indoor air quality consultants use in residential buildings is only appropriate for detecting chemicals in industrial environments. Other companies try to “pad” their reports by making determinations – such as reporting levels of ammonia, nitrogen oxides and benzene - that are usually irrelevant in residential and office buildings. Some companies also routinely report on the concentration of oxygen in the air, which never changes by meaningful amounts from outdoors to indoors.

If you live or work in a building in which indoor air quality testing was done, ask to see the report. Indoor air quality testing reports can be confusing to understand, though, so you may want to show the report to an indoor air quality consultant.

For more information on indoor air quality testing and indoor air quality testing reports, see My Office is Killing Me! The Sick Building Survival Guide, Jeffrey C. May (2006). Jeff May is also co-author of Jeff May’s Healthy Home Tips (2008). Both books are published by The Johns Hopkins University Press and are available on amazon.com.