Differences Of 1996 And 1997 SourcesContributions Of Volatile OrganicCompounds In Mexico City

The chemical mass balance (CMB) was applied to the volatile organic compounds (VOC) data base collected in Mexico City during the spring of 1996 and 1997 in conjunction with different source profiles collected during May through November 1997. The study of the contribution of VOC to the atmospheric pollution in large cities and its control has been conducted using the CMB receptor model. Samples of ambient air were simultaneously collected at three different sites, using stainless steel canisters and then analysed by gas chromatography with flame ionisation detection system. Each ambient sample was evaluated for the contribution from different sources of VOC (liquefied gas of petroleum, dry-cleaning, landfill, vehicle exhaust inside a tunnel, architectural and automotive painting, degreasing, graphic arts among others). The average 1996 results showed that the major sources of VOC for the three sites were: motor vehicle exhaust (54.9%, 57.4% and 63.8% for Xalostoc, Pedregal and La Merced, respectively), followed by liquefied petroleum gas with 28.5% in Xalostoc, 20.0% in Pedregal and 24.0% in La Merced. The average 1997 results for motor vehicle exhaust were 52.8%, 61% and 74.7%, followed by liquefied petroleum gas with 26%, 23.7% and 8%. Air Pollution VIII, C.A. Brebbia, H. Power & J.W.S Longhurst (Editors) © 2000 WIT Press, www.witpress.com, ISBN 1-85312-822-8