January 2015 - A research team from Georgia Tech, one of the U.S. Environmental Protection Agency’s (EPA) research grantees recently published an article in the Proceedings of the National Academy of Sciences on their research studying the effects of human-made pollutants on the formation of secondary organic aerosols (SOA).

Man-made pollutants can interact with vegetation-emitted organic compounds, turning them into airborne particles that have substantial impacts on climate, air quality and human health. However, the extent to which human activities impact the formation of SOA in the atmosphere is still poorly understood.

This research provided direct evidence on the magnitude of man-made influence on SOA formation in Southeastern United States. The study found that certain emissions from cars and coal-fired power plants, specifically sulfur dioxide and nitrogen oxides, directly and substantially mediate the transformation of naturally occurring emissions from trees into SOA. Together, sulfur dioxide and nitrogen oxide can create 43-70% of total SOA in the southeastern US during summertime. This implies that future reduction of sulfur dioxide and nitrogen oxide pollution can considerably reduce the SOA burden in this part of the country.

The findings can greatly improve air quality and climate simulations in regions where man-made to biogenic interactions contribute significantly to SOA formation.

This research was funded in part by EPA, through a 2011 EPA solicitation Anthropogenic Influences on Organic Aerosol Formation and Regional Climate Implications. The research proposal solicitation called for research that will use measurements to improve understanding of the formation of organic compounds from a mixture of man-made and biogenic emissions and their climatically relevant properties. This project also received funding through the SCAPE Clean Air Research Center, the National Science Foundation (NSF) and the National Oceanic and Atmospheric Association (NOAA).

Full PNAS paper: Effects of Anthropogenic Emissions on Aerosol Formation from Isoprene and Monoterpenes in the Southeastern United States Exit