摘要:
以具有致癌毒性的多环芳烃(polycyclic aromatic hydrocarbons, PAHs)为对象,本研究于2014年1月(冬季)在湖北恩施农村地区使用煤炭和薪柴的家庭中同步采集了室内外空气样品,分析了室内外空气中28种PAHs(∑PAH28)的浓度水平、成分谱和粒径分布,重点比较了不同燃料家庭的污染特征差异,并据此估算了暴露人群的健康风险。结果表明,在燃煤家庭,∑PAH28的室内和室外浓度分别是(507±449) ng·m-3和(120±18) ng·m-3;而在燃柴家庭,其室内和室外∑PAH28浓度分别是(849±421) ng·m-3和(268±44) ng·m-3。受室内排放源影响,室内PAHs浓度显著高于室外,室内外∑PAH28浓度比值在2~13。颗粒态PAHs主要集中在细颗粒物上,PM1.0(空气动力学直径小于1.0 μm)上的PAHs占到颗粒态PAHs的50%~80%。燃煤家庭的居民因PAHs呼吸暴露导致的终生致癌风险的中位数是1.8×10-5(四分位距是1.2×10-5~3.1×10-5),使用薪柴的家庭人群暴露风险7.1×10-5(6.5×10-5~7.8×10-5)。无论是燃煤还是薪柴的家庭,居民因PAHs呼吸暴露导致的终生致癌风险均超过10-6的可接受风险水平,表明该地区的高浓度PAHs污染致使当地人群存在较高的致癌风险。
Abstract:
This study investigated household air pollution by polycyclic aromatic hydrocarbons (PAHs), a group of carcinogens, in rural homes through a field campaign during a winter period. Indoor/outdoor levels, composition profiles and size distributions were studied and compared between homes burning coals and wood. Health risks due to inhalation exposure to PAHs were evaluated by calculating increment lifetime cancer risk (ILCR). In homes burning coal, the total concentration of 28 PAHs (∑PAH28) was (507±449) and (120±18) ng·m-3 in indoor and outdoor air, respectively, while in homes burning woods, the ∑PAH28 was (849±421) and (268±44) ng·m-3, respectively. Due to the presence of indoor sources, indoor levels were much higher than the outdoor levels, with the indoor-outdoor ratio of ∑PAH28 ranging from 2 to 13. Most particulate PAHs, especially those high molecular weight ones, were enriched in fine particles. The mass fraction of particulate PAHs in fine PM1.0 was about 50%-80% of the total particulate ∑PAH28. The calculated median ILCR for the population burning coals was 1.8×10-5 (1.2×10-5-3.1×10-5 as the inter-quartile range), while for the population burning wood the median ILCR was 7.1×10-5 (6.5×10-5-7.8×10-5). In both groups, the ILCR was much higher than the acceptable level of 10-6, indicating high health risks due to severe air pollution by PAHs in the study area.
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