Identifying PM_(2.5) and PM_(0.1) Sources for Epidemiological Studies in California

摘要

The University of California-Davis_Primary (UCD_P) model was applied to simultaneously track ～900 source contributions to primary particulate matter (FM) in California for seven continuous years (January 1st, 2000 to December 31st, 2006). Predicted source contributions to primary PM_(2.5) mass, PM_(1.8) elemental carbon (EC), PM_(1.8) organic carbon (OC), PM_(0.1) EC, and PM_(0.1), OC were in general agreement with the results from previous source apportionment studies using receptor-based techniques. All sources were further subjected to a constraint check based on model performance for PM trace elemental composition. A total of 151 PM_(2.5) sources and 71 PM_(0.1) sources contained PM elements that were predicted at concentrations in general agreement with measured values at nearby monitoring sites. Significant spatial heterogeneity was predicted among the 151 PM_(2.5) and 71 PM_(0.1) source concentrations, and significantly different seasonal profiles were predicted for PM_(2.5) and PM_(0.1) in central California vs southern California. Population-weighted concentrations of PM emitted from various sources calculated using the UCD_P model spatial information differed from the central monitor estimates by up to 7796 for primary PM_(2.5) mass and 148% for PM_(2.5) EC because the central monitor concentration is not representative of exposure for nearby population. The results from the UCDP model provide enhanced source apportionment information for epidemiological studies to examine the relationship between health effects and concentrations of primary PM from individual sources.