Volatile Organic Compounds in the Atmosphere of Mexico City

64 VOCs, including 36 toxic VOCs, were measured at four sites in the Mexico City Metropolitan Area (MCMA) during 2011-2012. Results showed that Iztapalapa-area presented the highest VOC concentrations, and that VOC compounds related to LPG leakages exhibited the highest concentrations. Acetone and ethanol were the toxic VOCs that showed the highest average concentration (31.9±4.6, 30.8±3.9 ppb). Correlation analysis among measured VOCs indicates that they come from vehicular emissions and industrial sources. Compared to the former field measurement campaign of 2005-2006, the ozone formation potential (OFP) has been reduced by 53%. Based on these results, we propose as alternatives to control ground-level ozone formation in the MCMA to limit the use of oil-based paints, and to restrict the use of vehicle model years prior to 1991, which still use carburetors.