Recent technological advances have allowed the development of robust and rapid response (~1 s) instrumentation with high sensitivity which can be deployed on a variety of mobile platforms. A new mobile laboratory equipped with gas and particulate measurement instrumentation was operated during the Mexico City Metropolitan Area 2003 field campaign. Chemically speciated and size resolved aerosol mass was measured with an aerosol mass spectrometer. Selected trace gases (NOx, O3, SO2, NO2, CH2O, NH3, NOY, CO2) were measured with various optical techniques. The mobile lab also carried a proton transfer reaction mass spectrometer (PTRMS) for speciation of some gas phase organic components.

Measurement goals of the mobile lab included characterizing emission ratios from in-use vehicles (vehicle chase experiments) and to identify pollutant sources in and around the Mexico City area. Results from this campaign will be presented which highlight the elevated pollutant levels typical of the Mexico City area. Emission ratios from Mexico City vehicles will be compared to vehicle emission ratios previously measured with the mobile lab in New York City.