Respiratory Emergency Department Visits Linked to Poor Air Quality

There were statistically significant positive associations between ozone and all respiratory emergency department visits in all age groups.

Living in areas with higher levels of ozone and fine particulate matter (PM2.5) was associated with more respiratory-related emergency department (ED) visits than living in areas with higher air quality, according to study results published in the American Journal of Respiratory and Critical Care Medicine.

Daily respiratory disease ED visits from 17 states were matched to ozone and PM2.5 ambient air quality measurements and comparisons were made between areas with low and high air quality, corresponding to high or low amounts of ozone and PM2.5 in the ambient air.

Of the 38.4 million respiratory ED visits, the data were from 869 counties and represented 45% of the US population. Children and adults (ages 18-65) had approximately 16 million visits each whereas older adults (≥65) had about 6 million visits.

Daily rates of respiratory ED visits were 1.20 for all ages combined, 1.94 for children, 0.91 for adults, and 1.37 for older adults per 10,000 people. The daily 8-hour maximum ozone varied from 8.0 ppb to 34.0 ppb, with a mean interquartile range of 16.54 ppb. The 24-hour average PM2.5 level was 5.3 μg/m3 and ranged from 1.9 to 9.8 μg/m3. There was a statistically significant positive association between ozone and all respiratory ED visits in all age groups. The rate ratio per 10 μg/m3 increase in PM2.5 in ozone for all respiratory ED visits was 1.02, but the rate ratios between all respiratory ED visits combined and PM2.5 were higher in children vs adults.

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The researchers wrote, “Our nationally relevant study, based on nearly 40 million respiratory ED visits representing all ages, addresses an important gap in air pollution epidemiology and is a valuable reference for future national air pollution standards.”

They added, “Our results support the [Environmental Protection Agency]’s determination of a likely causal relationship between PM2.5 and respiratory effects and a causal relationship between ozone and respiratory effects.”


Strosnider H, Chang H, Darrow L, Liu Y, Vaidyanathan A, Strickland MJ. . Age-specific associations of ozone and PM2.5 with respiratory emergency department visits in the US [published October 2, 2018]. Am J Respir Crit Med. doi:10.1164/rccm.201806-1147OC