A recent study shows 25 percent of the tiny particulates people breathe inside academic buildings may contain contaminants associated with outdoor pollution, The Herald Journal reported.
Randy Martin, lead author of the study and associate research professor of environmental engineering at Utah State University, studied the effects of outdoor pollution on indoor air quality on red air quality days, KSTU Fox affiliate reported.
Air quality is considered unhealthy for the general population once it is classified as red, or an index value of 151 to 200 on the American Lung Association’s air quality index. The American Lung Association advises people who may be susceptible to pollution to avoid staying outdoors, including children, adults who are active and those who have a respiratory disease and others who should avoid participating in strenuous outdoor activities or exercise.
While people may think they are safer indoors, they are still exposed to outdoor particulates. Martin found ammonium nitrate in the air volatilizes as it reaches the inside of buildings, according to KSTU Fox affiliate. When particles heat up as they mix with indoor air, they dissolve. However, red air quality days usually happen during colder weather.
Dangers of tiny particulates on occupant health
Martin, along with graduate students, measured the levels of indoor and outdoor air pollution around Cache Valley, NPR affiliate KUER said. He focused on indoor air in schools within the valley and in buildings located at the campus of Utah State. He said particulate matter 2.5 micrometers or smaller in diameter dissipate into gas and become lower as it enters indoors and becomes warmer, The Herald Journal reported. Particulates that are PM 2.5 are tiny enough to enter the lungs and could affect how the body breathes.
“The 2.5 microgram size is the size that can penetrate all the way down into your respiratory system and deposit itself in the deepest lung tissue in the sacks which can interfere with your oxygen exchange in your capillaries,” Martin told ABC affiliate KTVX.
While schools could try to close all the windows and doors to avoid having outdoor air come inside, Martin suggested that this is not the best way to improve indoor air quality. He said buildings should be maintained at room temperature and to avoid opening windows on days when the air quality is poor or unhealthy. He recommended that buildings employ high-efficiency particulate air filters. Effective air cleaners such as these can capture indoor air impurities and replace them with purified air for improved occupant health.
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