DERIVATION OF VOLATILE ORGANIC COMPOUNDS SURROGATE FOR THE MAXIMUM INCREMENTAL OZONE REACTIVITY IN MEXICO CITY METROPOLITAN AREA

Using a method developed by Lurmann et al. (1991), for lumped molecule or lumped-surrogate, we were able to define the respective base mixture for determining the re-activity of volatile organic compounds (VOCs) in ozone formation in the Mexico City metropolitan area (MCMA). A sampling campaign for collecting VOCs was carried out to determine the individual compounds in the MCMA atmosphere. Samples were collected simultaneously in stainless steel canisters at six sites: Xalostoc, Pedregal, Tlalnepantla, Cerro de la Estrella, Instituto Mexicano del Petróleo, and la Merced. Seven samples were taken at each site during the sampling period. Ten VOC groups were established applying the Lurmann methodology, and each group was represented by one compound as follows: i) n-butane for the first alkane group, ii) n-octane for the second alkane group, iii) ethylene in a group by itself, iv) propene for the first olefin group, v) t-2-butene for the second olefin group, vi) toluene for mono alkyl benzenes, vii) m-xylene for the higher aromatics, viii) formaldehyde in a group by itself, ix) acetaldehyde for the aldehydes, and x) acetone for the ketones. The surrogate VO