Impacts of long-range transport of biomass burning on air quality in Texas.


The objective of this dissertation is to (1) provide a detailed analysis of the concentration, trends, and emission ratios of volatile organic compounds (VOCs) and trace gases in major cities in Texas: San Antonio, and Houston, and (2) investigate the physical and chemical properties of transported biomass burning (BB) smoke and their impact on background air quality in Port Aransas, an industrialized coastal site in Texas. To achieve these objectives, mobile and stationary field experiments were conducted to measure the impact of local emissions and transported pollution on air quality in Texas cities. The inter-site comparison of VOCs and trace gases across the San Antonio metropolitan area revealed significant geospatial and temporal variabilities in emissions and processing within this metropolitan area. Further, VOCs concentrations and emission sources were compared for two growing Texas locations in San Antonio and Houston. The results indicate that Texas cities have complex emission scenarios and that future efforts to mitigate ozone (O3) and particulate matter may require various emission reduction strategies. Two long-range transport BB events (BB1 and BB2) were identified at Port Aransas. Several aerosol- and gas-phase BB tracers were evaluated to identify and characterize these long-range transported BB events in an industrialized location. The aerosol composition and optical properties exhibited good agreement with the BB designation, while acetonitrile and carbon monoxide (CO) trends were less specific for identifying dilute BB plumes. The air pollutant measurements in Texas Commission on Environmental Quality (TCEQ) Continuous Ambient Monitoring (CAMS) and Black and Brown Carbon (BC2)- aerosol optical monitoring networks in Texas revealed potential regional impacts of these transported BB events on urban O3 levels. Overall, this chapter supports implementing an extended network of aerosol optical measurements to identify the influence of BB plumes, especially in cities designated as nonattainment or marginal nonattainment of criteria air pollutants.