Particulate matter levels and trends in Mexico City, Sao Paulo, Buenos Aires and Rio de Janeiro

Abstract

Air pollution monitoring in Mexico City, Sao Paulo, Buenos Aires and Rio de Janeiro had already started by the end of the sixties. Monitoring slowly improved as a function of time and became more generalized and systematic by the mid-eighties, at least in three of the four megacities. Particulate matter levels, measured as smoke or gravimetrically determined by Hi-Vol sampling ( WHO, 1976, Offset Publication No. 24, Geneva.), have routinely and consistently been followed at quite a number of sites. To a lesser extent inhalable particulate matter levels (PM 10) and ambient lead levels have also been investigated in a number of (exploratory or routine) monitoring campaigns. A review is given of the historical data, the present levels and their trends as a function of time and space. Emission data, source information and local topographical and climatological data supplement the picture. In Sao Paulo as well as in Rio de Janeiro average and extreme levels almost systematically decreased as a function of time, but air quality standards are still exceeded in roughly 50% of the sites. In Mexico City SPM-levels increased up to the mid-eighties, and stabilized at levels (significantly) above the air quality standards. Due to a lack of reliable data the situation in Buenos Aires is not clear at all.