Separation of emitted and photochemical formaldehyde in Mexico City using a statistical analysis and a new pair of gas-phase tracers

[摘要] Photochemical pollution control strategies require an understanding ofphotochemical oxidation precursors, making it important to distinguishbetween primary and secondary sources of HCHO. Estimates for the relativestrengths of primary and secondary sources of formaldehyde (HCHO) wereobtained using a statistical regression analysis with time series data ofcarbon monoxide (CO) and glyoxal (CHOCHO) measured in the Mexico CityMetropolitan Area (MCMA) during the spring of 2003. Differences betweenEaster week and more typical weeks are evaluated. The use of CO-CHOCHO asHCHO tracers is more suitable for differentiating primary and secondarysources than CO-O₃. The application of the CO-O₃ tracer pair tomobile laboratory data suggests a potential in-city source of backgroundHCHO. A significant amount of HCHO observed in the MCMA is associated withprimary emissions.

[学科分类] 大气科学