我国113个城市大气颗粒物污染的健康经济学评价

  目的  了解山东省潍坊市大气颗粒物中6种重金属元素的时间、空间分布及其来源，评价其人群健康风险。  方法  于2014年1 — 10月在潍坊市5个采样点采集PM₁₀和PM_2.5样品，采用原子吸收法分析6种重金属元素含量，因子分析法识别其主要来源，采用美国环保署推荐的健康风险评价模型进行呼吸途径摄入的人群健康风险评价。  结果  PM₁₀和PM_2.5样品中除了Cd浓度水平具有季节差异（P < 0.05）外，Pb、Cu、Mn、Ni、Cr浓度水平均无季节差异（P > 0.05），而6种重金属元素浓度水平均表现为功能区差异（P < 0.05）；因子分析结果表明，PM₁₀中重金属主要来源于交通污染、工业污染和道路扬尘，分别占44.85 %、22.09 %和18.16 %；PM_2.5中重金属主要来源于工业污染、道路扬尘和交通污染，分别占48.54 %、23.60 %和14.10 %；颗粒物样品中重金属通过呼吸道暴露的非致癌风险均 < 1，致癌风险接近于阈值水平。  结论  潍坊市普通人群吸入颗粒物中重金属的非致癌风险处于可接受水平，但致癌风险接近阈值范围。

Distribution and health risk assessment of heavy metals in surface dusts of Maha Sarakham municipa-lity

  Objective  To analyze temporal and spatial distribution and sources of heavy metals in ambient air particulate matter less than 10 μm in aerodynamic diameter (PM₁₀) and less than 2.5 μm (PM_2.5) in Weifang city and to assess the health risks due to exposure to the heavy metals.  Methods  We collected ambient air PM₁₀ and PM_2.5 samples at five monitoring sites in different function regions of Weifang city during January, April, July, and October 2014. The concentrations of 6 heavy metals were detected with atomic absorption spectrometry and the sources of 6 heavy metals were analyzed by factor analysis. Health risk assessment on respiratory exposures to these heavy metals was performed using the risk assessment model recommended by United States Environment Protection Agency.  Results  No significant seasonal variations were observed in concentrations of lead (Pb), copper (Cu), manganese (Mn), nickel (Ni) and chromium (Cr) in PM₁₀ and PM_2.5 samples (P > 0.05 for al), except for in the concentration of cadmium (Cd) (P < 0.05); however, the concentrations of the 6 heavy metals in PM₁₀ and PM_2.5 samples differed significantly by monitoring sites of various functional regions (P < 0.05). Factor analysis indicated that the heavy metals in PM₁₀ samples were mainly from traffic pollution, industrial pollution and road dust, accounting for 44.85%, 22.09% and 18.16% of the total content; the heavy metals in PM_2.5 samples were mainly from industrial pollution, road dust and traffic pollution, accounting for 48.54%, 23.60% and 14.10% of the total content, respectively. Non-carcinogenic risks due to respiratory exposure to the heavy metals in the fine particulate matter are all less than 1; but the carcinogenic risks due to the exposures are close to the threshold levels.  Conclusion  Non-carcinogenic risk due to respiratory exposure to heavy metals in fine particulate matter is acceptable, but carcinogenic risk due to the exposure close to the threshold level for the residents in Weifang city.