Compound Specific Measurement of Stable Carbon Isotope Ratios of Atmospheric Secondary POM
Abstract
Atmospheric composition and the chemistry of particulate matter (PM) suspended in the atmosphere have been of great interest to the scientific community. Atmospheric particulate organic matter (POM) adversely affects health and climate, and the development of effective strategies to mitigate these adverse impacts requires understanding the origin and transformations of particulate matter suspended in the atmosphere. One of the still poorly understood sources of POM is the formation of secondary POM from the photo-oxidation of atmospheric volatile organic compounds (VOC). Nitrophenols are semi-volatile compounds that are formed specifically from the toluene + OH reaction and will be the focus of this study. Isotope ratio measurements are an emerging tool to gain new insight into the atmospheric chemistry of organic compounds. Laboratory smog chamber and flow reactor experiments have demonstrated that nitrophenols formed by photo-oxidation of toluene are about 4-5‰ lighter than the precursor. This information can be used in conjunction with ambient concentration and stable carbon isotope ratio measurements to distinguish between primary and secondary POM. In this presentation, results of atmospheric measurement of concentrations and stable carbon isotope ratio of nitrophenols will be presented. It will be demonstrated that isotope ratio measurements provide new insight into the origin of POM and the processes that determine the distribution of semivolatile organic compounds between gas and particle phase.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2012
- Bibcode:
- 2012AGUFM.A53N0340S
- Keywords:
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- 0300 ATMOSPHERIC COMPOSITION AND STRUCTURE;
- 0305 ATMOSPHERIC COMPOSITION AND STRUCTURE / Aerosols and particles;
- 0345 ATMOSPHERIC COMPOSITION AND STRUCTURE / Pollution: urban and regional;
- 0365 ATMOSPHERIC COMPOSITION AND STRUCTURE / Troposphere: composition and chemistry