The purpose of this study was to study the spatial and temporal variation of BTEX in the ambient air of Leon, Guanajuato, Mexico, to assess the inhalation health risk to the local population from exposure to these compounds. BTEX were monitored using passive samplers during two sampling seasons (rainy 2019 and cold dry 2020), and samples were analyzed by gas chromatography with flame ionization detection. BTEX ratios and meteorological analysis suggested that the concentrations were mainly influenced by vehicular and local sources located to the SE of the study area. The sum of average concentrations of BTEX in rainy and cold dry seasons were of 3.52 ± 0.36 µg m⁻³ and 4.11 ± 0.38 µg m⁻³, respectively. Mean concentrations were of 0.74, 1.59, 0.48, and 0.69 µg m⁻³, for benzene, toluene, ethylbenzene, and p-xylene, respectively. The highest levels of BTEX were found in sites with an urban land-use type of medium-intensity industrial zones with high population density. The lower BTEX concentrations found during the rainy season were probably due to higher solar radiation and temperatures that favored their photochemical degradation. Bi-variate and multivariate analysis showed that the BTEX species were strongly correlated with each other and with temperature and solar radiation, indicating that they originated from common sources. Benzene and toluene correlated strongly with CO and SO₂, indicating that they could originate from vehicular exhaust emissions and high-sulfur fuel combustion sources. The health risk assessment showed that the Leon city adult population is at possible risk of developing cancer in their lifetime due to exposure to the measured benzene levels, but indicated no risk of contracting respiratory and cardiovascular diseases due to inhalation of BTEX. The results suggest the need for BTEX emissions reduction policies in the study area, as well as the establishment of a Mexican standard that regulates the maximum permissible limit of these pollutants in ambient air in order to protect the health of the population.

这项研究的目的是研究墨西哥瓜纳华托州莱昂市环境空气中BTEX的时空变化，以评估暴露于这些化合物对当地居民的吸入健康风险。在两个采样季节（多雨的2019年和冷干的2020年）中，使用无源采样器对BTEX进行了监测，并通过带有火焰离子化检测的气相色谱仪对样品进行了分析。BTEX比率和气象分析表明，该浓度主要受位于研究区域东南部的车辆和本地资源的影响。在雨季和寒冷的干燥季节，BTEX的平均浓度总和分别为3.52±0.36 µg m ^-3和4.11±0.38 µg m ^-3。平均浓度分别为0.74、1.59、0.48和0.69 µg m ^-3分别用于苯，甲苯，乙苯和对二甲苯。BTEX含量最高的地区是城市土地利用类型的人口密集的中等强度工业区。在雨季发现的较低的BTEX浓度可能是由于较高的太阳辐射和温度有利于它们的光化学降解。双变量和多变量分析表明，BTEX种类彼此之间以及与温度和太阳辐射密切相关，表明它们起源于共同的来源。苯和甲苯与CO和SO ₂密切相关，表明它们可能源自车辆废气排放和高硫燃料燃烧源。健康风险评估表明，莱昂市成年人口由于暴露于测得的苯水平而有可能在其一生中患上癌症，但并没有因吸入BTEX而染上呼吸道和心血管疾病的风险。结果表明，研究区域需要制定BTEX减排政策，并制定墨西哥标准，以规范环境空气中这些污染物的最大允许限量，以保护人们的健康。