Observations of organic aerosol mass (OA) growth downwind of urban and industrial source in Houston Area
Abstract
During TexAQS-2006 field study, organic aerosol mass (OA)downwind of Houston urban center and the petrochemical industries along the Houston Ship Channel was measured aboard the NOAA WP-3D aircraft, using a compact time-of-flight aerosol mass spectrometer (C-ToF-AMS). We have used on-board measurements of CO, benzene, and SO2 to identify the different plumes transected on several days in order to characterize the growth of OA with transport downwind of the sources. The results show that the OA growth in urban plume is similar to other urban centers in NE U.S. However, the observed growth in OA downwind of Houston Ship Channel exceeds those observed downwind of urban centers. We also present results from a chemical box model that was developed to simulate secondary organic aerosol (SOA) formation in the urban and industrial plumes, using absorbing- mass dependent and the most recent NOx dependent aerosol formation yields. Furthermore, we used a transport model, FLEXPART, along with the EPA BEIS biogenic emission inventory, to estimate isoprene and monoterpene surface contributions to the air masses sampled on two flights. Using constant aerosol formation yields, the amount of OA that could be formed from these biogenic precursors was estimated to be less than 1.5 ug m-3, even during a flight to the north of Houston where high biogenic emissions are observed. The tight correlation between the observed OA and CO on this flight also indicates that anthropogenic sources play the dominant role in OA formation in Houston area.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2008
- Bibcode:
- 2008AGUFM.A24A..07B
- Keywords:
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- 0300 ATMOSPHERIC COMPOSITION AND STRUCTURE;
- 0305 Aerosols and particles (0345;
- 4801;
- 4906);
- 0325 Evolution of the atmosphere (1610;
- 8125);
- 0345 Pollution: urban and regional (0305;
- 0478;
- 4251);
- 0365 Troposphere: composition and chemistry