Children who are exposed to a certain type of environmental air pollution are more likely to contract community-acquired pneumonia or CAP, and to be hospitalised for longer periods of time, said a new study led by researchers in the Louisiana State University Superfund Research Program.

Social factors, including race and socioeconomic status, were also found to be associated with living in high-risk areas for CAP, said the study published in the scientific journal Experimental Biology & Medicine.

“This research contributes to the body of evidence linking poor respiratory health to exposure to environmental air pollution, especially combustion-derived particulate matter,” said study co-author Stephania Cormier, who leads the LSU Superfund Research Program. Research conducted by LSU Superfund Research Program scientists has shown similar patterns for other respiratory diseases including asthma, and recent data suggest implications for COVID-19.

Using data from a Centers for Disease Control surveillance study of pediatric pneumonia and geographic information systems, the investigators identified high- and low-risk areas for CAP in the metropolitan area of Memphis, Tennessee.

They collected information including the cause of the child’s pneumonia, such as a bacterial or viral infection, public versus private health insurance, age, race and exposure to particulate matter pollution less than 2.5 micrometers in diameter, or PM2.5. These tiny particles in the air are released by industrial combustion, car exhaust and forest fires. PM2.5 is one of the six air pollutants regulated by the Environmental Protection Agency, or EPA, and is linked to higher rates of respiratory tract infections and a plethora of other health problems, including cardiovascular disease.

When analysed independently, race, type of insurance and exposure to PM2.5 were all identified as significant risk factors associated with residence in areas with higher-than-expected CAP. However, race was the most significant factor associated with living in a high-risk area. In the Memphis metropolitan area, Hispanic and non-Hispanic Black children were hospitalized for pneumonia at significantly higher rates compared with white children.

Another important finding from this study is that the health risk associated with high PM2.5 occurred at levels below the current regulatory maximum standard set by the EPA.