Semicontinuous measurements of organic carbon and acidity during the Pittsburgh air quality study: implications for acid-catalyzed organic aerosol formation
- Carnegie Mellon University, Pittsburgh, PA (United States). Departments of Chemical Engineering, Civil and Environmental Engineering, Engineering and Public Policy
Laboratory evidence suggests that inorganic acid seed particles may increase secondary organic aerosol yields secondary organic aerosol (SOA) through heterogeneous chemistry. Additional laboratory studies, however, report that organic acidity generated in the same photochemical process by which SOA is formed may be sufficient to catalyze these heterogeneous reactions. Understanding the interaction between inorganic acidity and SOA mass is important when evaluating emission controls to meet PM2.5 regulations. Semicontinuous measurements of organic carbon (OC), elemental carbon (EC), and inorganic species from the Pittsburgh Air Quality Study were examined to determine if coupling in the variations of inorganic acidity and OC could be detected. Significant enhancements of SOA production could not be detected due to inorganic acidity in Western Pennsylvania most of the time, but its signal might have been lost in the noise. If a causal relationship between inorganic acidity and OC is assumed, reductions in OC for Western Pennsylvania that might result from drastic reductions in inorganic acidity were estimated to be 2 {+-} 4% by a regression technique, and an upper bound for this geographic area was estimated to be 5 {+-} 8% based on calculations from laboratory measurements. 48 refs., 7 figs., 3 tabs.
- OSTI ID:
- 20752114
- Journal Information:
- Environmental Science and Technology, Vol. 40, Issue 7; Other Information: spyros@andrew.cmu.edu; ISSN 0013-936X
- Country of Publication:
- United States
- Language:
- English
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