Improving the Source Identification andApportionment of Volatile Organic Compounds inHouston, TX

摘要

Hourly concentrations of ambient volatile organic compounds (VOCs) were analyzedrnbetween June and October 2003 at three sites in order to further understand emissions ofrnVOCs in the Houston area and the role of specific sources and source areas. Ambientrnconcentrations of 54 VOCs from three monitoring sites in the heavily industrializedrnHouston Ship Channel (Wallisville Road, HRM-3 Haden Road and Lynchburg Ferry)rnwere analyzed using Positive Matrix Factorization (PMF). Hourly concentrations werernaggregated into weekly composites and analyzed to determine the most important sourcerntypes that contribute to the measured VOC concentrations at these three sites. For eachrnmonitoring site, three or four sources were identified for each week as major contributorsrnto ambient VOC concentrations using PMF. Non-methane hydrocarbon (NMHC) massrnwas well reconstructed by the PMF model using a multiple linear regression betweenrnisolated source strength and measured NMHC mass. The sources isolated by the modelrnare consistent with the chemical compositions of refinery, petrochemical and evaporativernemissions, which are also the dominant inventoried sources of VOCs in Houston ShiprnChannel region. The results and implications of this study will further be used to betterrnunderstand the relationship between VOC emissions and ozone formation and to validaternexisting VOC emission inventories.