Determination of volatile organic compounds source profiles in Mexico City

The ozone standard is exceeded more than 300 days a year in Mexico City, therefore it is imperative to reduce the atmospheric concentrations of its precursors, NOx and VOC. There is no pollution standard index nor regulation for volatile organic compounds (VOCs) in Mexico City and the concentrations of these compounds are two orders of magnitude than those found in California. On the other hand, many individual components of VOC have been identified as hazardous air pollutants and thus require control. The Chemical Mass Balance (CMB) model has been used to determine the apportionment of the VOC sources. This model requires the profiles of each VOC emission sources. In this paper the dry cleaning, graphic arts, degreasing and painting operations, VOC source profiles are presented. In Mexico, this is the first time that these profiles are experimentally determined. The characterization of more than 100 compounds was carried out during several sampling periods in different sites of each source, using stainless steel SUMMA(R) canisters and subsequent analysis by gas chromatography with flame ionized detector. It was found that some species are characteristic for each source profile, although the standard deviations were high for the different sites of each source.