Determinação simultânea de hidrocarbonetos policíclicos aromáticos em material particulado e na fase gasosa no ar de Belo Horizonte, Brasil, utilizando CF-SPME-GC/MS

Abstract

Simultaneous Determination of Polycyclic Aromatic Hydrocarbons on Atmospheric Particulate Matter and Gas Phase in Belo Horizonte, Brazil, Using CF-SPME-GC/MS. The atmospheric pollution by particulate matter (PM) is a worldwide concern due to its great impacts on human health, especially because of MPs ability to adsorb toxic substances. Among them there are the polycyclic aromatic hydrocarbons (PAHs), which are known carcinogenic and mutagenic compounds. Particulate matter with aerodynamic diameter smaller than 2.5 m (PM2.5), found in theatmosphere of the Brazilian city of Belo Horizonte MG, was collected using a high volume sampler, for a one-year period. The sampling was performed next to a high traffic avenue. The average concentration of PM2.5 in this period was calculated and found to be 36.39 g.m-3. Thisconcentration is way above the 10 g.m-3 value stablished by the World Health Organization (WHO) as the threshold for a one-year period.The particulate matter was analyzed and the concentration of 16 PAHs was determined. These PAHs are defined by the American Environmental Protection Agency as priority pollutants. For the analysis, the cold fiber direct immersion solid phase microextraction technique was employed, followed by gas chromatography coupled with mass spectrometry. The annual mean concentration of the PAHs on the PM2.5 was 3.89 ng m-3. Simultaneously to the sampling of PM2.5, the gas phase was also collected, using a polyurethane foam. A method, similar to the one utilizedwith the PM2.5, was employed for determining the concentration of the 8 PAHs of smaller molecular mass, normally found at the gas phase in the atmosphere. The concentration was 12.55 ng.m-3. With those PAHs concentrations, the Benzo(a)pyrene equivalent was calculated and foundto be 0,94 ng.m-3. This marker is employed to determine the incremental cancer risk to which a population is exposed in a lifetime period of approximately 70 years. For this study, the value found was 82/1,000,000. The possible emission sources of the PAHs were also determined, bytheir isomeric ratios. The main sources are fossil fuel and biomass burning. These results confirm the importance of controlling this kind of pollution.