Analysis of PM2.5 in the atmosphere over Southeast Texas Region.

摘要

This thesis study performed PM2.5 trend analysis for the Southeast Texas Region based on the EPA measurement data in the region during the years from 2003 through 2007, and conducted experimental analysis to characterize the mass and chemical composition of PM samples collected from the TCEQ Lamar Monitoring Station during a period from 2007 to 2008. In addition to measure the mass and chemical composition of PM2.5 in the region, a source apportionment study was also conducted based on the PMF analysis of the EPA measured PM2.5 chemical speciation data to identify the major sources contributing to the observed PM2.5 in the region. The analysis of PM data in the region has indicated that the PM2.5 mass concentration and chemical composition are in general spatially homogenous throughout the region and that the PM2.5 mass concentration is generally higher both in early morning and late afternoon. The PMF analysis of the data from three monitoring sites in the region has identified nine common sources: sulfate-rich secondary aerosol, motor vehicle, wood burning, road dust, metal processing, aged sea salt, nitrate-rich secondary aerosol, soil, and sea salt. It has been observed that the sulfate, nitrate, and soil sources from the three sites show similar chemical composition and seasonal variation indicating the regional characteristics of these sources. The results from PM experiments have indicated that sulfate and carbon contribute the most to the PM2.5 samples collected from the Lamar Monitoring Station.