Chemical characterization of volatile organic compounds near the World Trade Center: Ambient concentrations and source apportionment

Concentrations of 53 volatile organic compounds (VOCs) are reported from four locations near the World Trade Center (WTC) (New York, USA) complex for canister samples collected from September 2001 through January 2002. Across the four sampling sites, mean concentrations ranged from 94.5 to 219μgm-3 for total VOCs. The highest mean concentrations for individual VOCs at any site were for ethane (18.7μgm-3), isopentane (17.1μgm-3), and m,pm,p-xylenes (17.0μgm-3). VOC concentrations were generally highest for samples collected north and west of the WTC complex. Concentrations of total VOCs (and most individual VOCs) decreased from the period when fires were present at the WTC complex (before 19 December 2001) to the period after fires. The EPA Unmix Version 5.0 receptor model was used to assess the impact of WTC fires and recovery efforts on ambient VOC concentrations. Four factors were identified: burning of building debris, a mixed recovery/heating source, motor vehicle exhaust, and a mixed gasoline source.