Resumen
Since 1991, volatile organic compounds (VOC) have been determined in Mexico City metropolitan area (MCMA) using different analyzing methods. samples collected in catridges and canisters are analyzed by gc-ms and hplc. continuos monitoring by a long path differential absorption analyzer (DOAS) has also been performed. The Mexican Petroleum Institute (IMP) along with the USEPA and the collaboration of the Mexican environmental authorities have performed, following the EPA TO-14 method, four sampling campaigns of ambient air in canisters among 1992 and 1993. The campaigns were designed to be performed during March, month in which the worst ozone episodes have taken place. Additional sampling was performed in November in order to compare diferences between seasons.In March 1993, samples in three different kinds of cartridges were used which selectively absorb carbonyl compounds, light hydrocarbons (C2-C4) and heavier hydrocarbons (C5-015).