Even When Sedentary, Lung Function Drops in Healthy Adults After Exposure to Low Level Ozone


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“The NAAQS of 0.07 ppm likely does not adequately protect the general healthy adult population, and in particular women, from repeated long-term exposures to O3 air pollution.” – Michelle L. Hernandez, MD, FAAAAI

An abstract originally scheduled for presentation at the 2020 Annual Meeting of the American Academy of Allergy, Asthma & Immunology (AAAAI) before its cancellation due to coronavirus disease 2019 (COVID-19), demonstrates that exposure to low level ozone causes lung function to drop in healthy adults even while sedentary and not exercising.

Ozone (O3) is both natural and man-made, but ambient ground level ozone is a result of human activity. When people inhale ozone it can lead to adverse health effects. This is particularly true for people with asthma, as ozone is a known trigger for asthma attacks even if the concentrations are below the 8-hour National Ambient Air Quality Standard (NAAQS) of 0.07 parts per million (ppm). However, recent large-scale population studies have also reported that long-term exposure to ozone levels below the standard increase the risk of cardiovascular and respiratory deaths.

For this study, researchers examined if healthy adults exposed to ozone concentrations at the NAAQS while sedentary (mimicking what most of the population would experience) would produce changes in lung function and airway inflammation. The researchers purposely limited the amount of exercise, since vigorous exercise can increase the total dose of ozone that someone can inhale. Fourteen healthy, non-smoking participants completed this study where they were exposed to either filtered clean air or to an average ozone concentration of 0.07 ppm while sedentary for over six hours. They underwent lung function testing before and after each exposure, and provided both lower and upper airway samples to look for inflammation.

The results showed that ozone caused significant drops in lung function and increases in upper and lower airway inflammation, and that these effects were more pronounced in women. “Essentially what this means is that independent of exercise, ozone exposure at the NAAQS can still negatively impact respiratory outcomes in healthy individuals, and this effect is greater in women. The NAAQS of 0.07 ppm likely does not adequately protect the general healthy adult population, and in particular women, from repeated long-term exposures to O3 air pollution,” explains first author of the study, Michelle L. Hernandez, MD, FAAAAI.

This data further illustrates how low level ozone has an impact not only on those with health conditions such as asthma, but also those who are in good health, even when they’re not physically active. “We urge everyone to do what they can to limit exposure to ozone and other harmful pollution,” said Dr. Hernandez. “While large scale change will need to come from public policies, individuals can take steps to limit unhealthy exposure such as limiting time outdoors when air quality is poor.”

Visit aaaai.org to learn more about air pollution and asthma. This research was published in an online supplement to The Journal of Allergy and Clinical Immunology.

The American Academy of Allergy, Asthma & Immunology (AAAAI) represents allergists, asthma specialists, clinical immunologists, allied health professionals and others with a special interest in the research and treatment of allergic and immunologic diseases. Established in 1943, the AAAAI has over 7,000 members in the United States, Canada and 72 other countries. The AAAAI’s Find an Allergist/Immunologist service is a trusted resource to help you find a specialist close to home.

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