With new national clean air protections in place, a UNC-Chapel Hill study shows future air quality measures may need to be more localized.
Tiny air-polluting particles known as fine particulate matter or PM2.5 can be harmful to human health. The EPA recently lowered the allowable levels of the particles from 12 to 9 micrograms per cubic meter.
"The regulations are currently based upon total mass without focusing on what the components are," said UNC professor Sarav Arunachalam. His study found that PM2.5 levels have decreased nationally but the chemical composition of the particles varies from place to place, where some can be more toxic than others.
For example, Arunachalam says North Carolina's PM2.5 composition is affected by its trees. That's different from places in the Western US, where wildfires might contribute more to that chemical makeup.
With that in mind, Arunachalam says targeting these regional differences may be key to future air quality improvement efforts that benefit public health.