VOC Signatures at Selected Urban Sites in Mexico City during the MCMA 2002 and 2003 Field Campaigns

During the MCMA 2002 and 2003 field campaigns, ambient VOC concentrations were measured using automated canister sampling methods at several urban sites within Mexico City. These data, along with previously reported measurements, are examined in terms of the similarities and differences that exist for locations near the urban core, in heavily industrial areas, and at downwind urban receptor sites. Data are also compared to similar measurements for US cities. The use of ratios of compounds at different locations is valuable for highlighting the effects of dilution versus chemical aging during transport from sources to receptors. These ratios can also be used to demonstrate the effects of local industrial sources on the VOC distribution at selected locations.