Concentration levels of atmospheric contaminants in Brazilian cities measured by passive sampling

Abstract

Measurements of air pollutants were made using passive sampling in Brazilian urban centers. The levels of SO2 and NO2 exceeded the WHO recommendations in São Paulo (SP), Londrina and Rio de Janeiro. Formaldehyde concentrations exceeded international recommendations in all urban centers and benzene concentrations exceeded 1.7 μg m−3, level associated with the probability of leukemia, according to the WHO. Sewage discharge in the Pinheiros River - SP and in Lake Pampulha - BH contributed to higher levels of H2S and NH3 in these urban centers. The BH atmosphere was also influenced by emissions from landfills. Organic and inorganic acids contributed similarly to atmospheric acidity. 71% of the calculated ratios between concentrations of formic and acetic acids were < 1, demonstrating the predominant influence of vehicle emissions on the atmospheric levels of these acids. Multivariate analysis showed that VOCs and organic acids are more influenced by temperature and solar radiation. The stronger direct relationship of NOx was with wind direction, showing competition between local emission and photochemical aging of these compounds brought from other locations. On a global scale, studies of this type are necessary and important to increase the accuracy of exposure estimates in different places where people live.