This study aims to determine BTEX concentrations in the Metropolitan Region of Rio de Janeiro (MRRJ, Brazil) and evaluate potential health risks of benzene and ethylbenzene exposure based on the collected data, in 2015, the year before the Rio 2016 Olympic Games. Samples were collected and analyzed following method TO-15 (U.S.EPA). Toluene was the most abundant compound in all samples (mean concentration 16.72 ± 15.70 µg m⁻³). The average benzene concentration in ambient air (3.44 ± 3.14 µg m⁻³) was slightly lower than the yearly average “upper assessment threshold”, 3.5 µg m⁻³, established by EU Directive 2008/50/EC. The calculated cancer risk values were > 1 × 10⁻⁶ for all samples, clearly indicating a potential cancer risk and the importance of fixed measurements by the monitoring stations to assess ambient air quality in the urban areas of the MRRJ. Calculated ratios for the BTEX species indicate that these compounds are predominantly emitted from vehicular sources with a contribution from industrial sources.

中文翻译：

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巴西里约热内卢奥林匹克都会区的环境水平和BTEX暴露的初步研究。

这项研究旨在确定里约热内卢大都会地区（巴西MRRJ）的BTEX浓度，并根据收集的数据（在2016年里约奥运会之前的2015年）评估苯和乙苯暴露的潜在健康风险。按照方法TO-15（USEPA）收集并分析样品。甲苯是所有样品中含量最高的化合物（平均浓度为16.72±15.70 µg m ^-3）。环境空气中的平均苯浓度（3.44±3.14 µg m ^-3）略低于欧盟指令2008/50 / EC制定的年度平均“上评估阈值” 3.5 µg m ^-3。计算出的癌症风险值> 1×10 ^-6对于所有样品，应清楚地表明潜在的癌症风险以及监测站进行固定测量以评估MRRJ市区空气质量的重要性。计算出的BTEX物质比率表明，这些化合物主要从车辆排放，而工业排放。