Research Projects

Many areas in California are out of compliance with air quality standards for fine particulate matter (PM2.5). Organic matter is a major constituent of PM2.5 mass on an annual basis. Quantitative, time-resolved knowledge of the composition of organic particulate matter is necessary to trace PM2.5 sources, to understand the formation and transformation processes, and to evaluate the roles of various PM2.5 components in air pollution and climate change. To support air quality and climate change researchers and regulators, this project would make hourly in-situ measurements of organic species in particulate matter in the southern San Joaquin Valley (SJV) during CalNex to improve understanding of PM2.5 sources and related atmospheric processing (e.g., chemistry). The measurements will be made over a six-week period to document the atmospheric variations in response to fluctuations in meteorological conditions and to systematic variations in emissions with time-of-day. These observations will form the basis for analyses aimed at understanding the sources and photochemistry controlling PM2.5 production in the study region and thus allow ARB to design more efficient emission control strategies.