Non-methane hydrocarbons in the vicinity of a petrochemical complex in the Metropolitan Area of São Paulo, Brazil

Abstract

Volatile organic compounds (VOCs) are fundamental in the atmospheric reactions, producing tropospheric ozone (O3) and secondary organic aerosols (SOA). We evaluated the hydrocarbons (HCs) near a petrochemical and industrial complex (PIC) in the metropolitan area of Sao Paulo (MASP). Air samples were hourly collected in two different sites during different days, 2016–2017. The most abundant compounds were toluene (1.5 ± 1.1 ppbv), cis-2-hexene (1.4 ± 1.9 ppbv), benzene (0.55 ± 0.66 ppbv), and m+p-xylene (0.58 ± 0.3 ppbv). HC concentrations observed at the BTP site (industrial) were approximately two times higher than those at the UFABC site (traffic). The aromatics presented the highest contribution at BTP (58%) and UFABC (56%). In addition, our comparison with other industrial areas worldwide showed a good agreement in the HC profile with Japan and the USA, suggesting the presence of similar emission sources. BTEX (benzene, toluene, ethylbenzene, m+p- and o-xylenes) correlations and ratios showed that despite vehicular emissions were the main sources of these compounds around PIC, there is the influence from industrial sources among others. Finally, to evaluate the potential impacts associated to PIC emissions, the formation of secondary pollutants was analyzed. Aromatic compounds represented ~98% and ~68% of the total SOA and O3 formation estimation, respectively. The lifetime cancer risk (LCR) for benzene was 5.75 × 10−6 and 4.25 × 10−6 for BTP and UFABC, respectively, which exceeds the US EPA recommendation (<1 × 10−6) and could negatively affect the populations health in this region