ChBE Seminar Series: Christopher Hennigan
Friday, September 20, 2013
10:00 a.m.-11:00 a.m.
Room 2108, Chemical and Nuclear Enginering Bldg.
Professor Jeffery Klauda
Closing the Gap on Missing Sources of Organic Aerosol in the Atmosphere
Dept. of Chemical, Biochemical & Environmental Engineering
University of Maryland, Baltimore County
Atmospheric particulate matter (PM), or aerosols, consist of a complex mixture of organic and inorganic compounds emitted by a number of diverse sources. More than 70 million people in the U.S. live in areas that exceed the EPAs annual limit for PM2.5 mass concentrations. Devising regulations to mitigate the PM problem is challenged by the fact that a significant fraction of PM2.5 is secondary compounds emitted into the atmosphere as gases which undergo reactions to form compounds that condense into the particle phase. This is especially problematic for secondary organic compounds, which typically makes up 25-50% of PM2.5 mass, but whose sources and formation are currently poorly understood. This is evidenced by the systematic underprediction of secondary organic aerosol (SOA) concentrations by state-of-the-art computer models. A focus of this talk will be on a potentially important source of SOA: the uptake and reaction of soluble organic gases in fine particle water. This pathway contributes significantly to SOA formation in Atlanta and Mexico City urban areas with completely different source influences and meteorology. Accounting for this process can help to explain the underprediction of SOA concentrations by models.