Researchers Document Links Between Pollution Levels, ED Visits for Breathing Problems

Researchers investigating the associations between ground-level ozone and fine particulate pollution (PM2.5) and emergency department (ED) visits for chronic obstructive pulmonary disease (COPD), asthma, and respiratory infections found that as levels rose, more patients land in the ED with breathing problems.

The authors said it was the largest US study of air pollution and respiratory ED visits of patients of all ages, and it came a few days after other researchers warned that the healthcare profession should treat climate change as a health emergency.

Ozone, the main ingredient of smog, and PM2.5, microscopic particles that penetrate the lung, are 2 forms of air pollution. The study looked at the levels of these 2 pollutants in 869 counties in the week prior to an ED visit for a breathing problem. The study included nearly 40 million ED visits for breathing problems, representing 45% of the US population.

The researchers divided patients into 3 groups: children under the age of 19, adults under the age of 65 and adults over the age of 65. The study found:

• An association between ozone and respiratory ED visits among all age groups, with the strongest association in adults under age 65. Per 20 parts per billion increase in ozone, the rate of an ED visit for respiratory problems increased 1.7% among children, 5.1% among adults under 65, and 3.3% among adults over 65.
• Increased levels of ozone resulted in increased visits for asthma, COPD, acute respiratory infections, and pneumonia. Overall the association was strongest for asthma among adults under 65.
• An association was found between PM2.5 and respiratory ED visits among children and adults under the age of 65, with the strongest association among children. Per 10 microgram per cubic meter increase in PM2.5, the rate of an ED visit increased 2.4% in children and 0.8% among adults under 65.
• Increased levels of fine particulate matter resulted in increased visits for asthma, acute respiratory infections and pneumonia.

The authors wrote that their study findings 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."

The study was published online in the American Thoracic Society's American Journal of Respiratory and Critical Care Medicine.

Reference

Strosnider HM, Chang HH, Darroow LA, et al. Age-specific associations of ozone and PM2.5 with respiratory emergency department visits in the U.S. [published online October 2, 2018]. Am J Respir Crit Care Med. doi: 10.1164/rccm.201806-1147OC.