Workers of São Paulo city, Brazil, exposed to air pollution: Assessment of genotoxicity

Air pollution affects all major urban centers, particularly megacities with populations greater than 10 million people. Vehicular and industrial emissions are among the most important sources of air pollutants in these cities. Air pollution composition, dose, and time of exposure can cause differential effects on human health. We have evaluated the genotoxic effects of air pollution (PM2.5 and NO2) on São Paulo city workers. Fifty-seven male individuals, 28-66 years old, with occupational exposure to air pollution, participated in this study; all worked daily outdoor shifts in São Paulo. Participants were recruited from three occupations: traffic controllers (n = 18); taxi drivers (n = 21); and workers at the Forestry Institute (n = 18). These workers were classified into two groups based on their workplace locations: Downtown Group (DT): traffic controllers and taxi drivers; Outskirts of Town Group (OT): workers at the Forestry Institute. Individual samplers of air pollution (Harvard air impactor) were used to collect PM2.5 and NO2 pollutants. Genotoxicity analysis (micronucleus test) was performed on buccal mucosa epithelial cells and peripheral blood lymphocytes. PM2.5 concentrations were significantly different between the groups (DT = 32.92 μg m−3, OT = 25.77 μg m−3; p = 0.03); however, no difference was observed in NO2 concentrations. Micronucleus frequencies in both buccal mucosa (DT = 2.78%, OT = 1.16%; p < 0.0001) and in peripheral lymphocytes (DT = 1.51%, OT = 0.73%; p < 0.0001) were significantly different between the groups. We observed a direct correlation between the individual dose of PM2.5 and micronucleus frequency in the buccal mucosa (p = 0.0021). Our results indicate that workers in the most urban areas of São Paulo are exposed to higher concentrations of PM2.5 and showed higher micronucleus frequencies in both buccal mucosa and lymphocytes.