郑州市环境空气中VOCs的污染特征及健康风险评价

Pollution condition and health risk assessment of VOCs in ambient air in Zhengzhou

挥发性有机物(VOCs)不但是引发霾和光化学烟雾等环境问题的重要原因,达到一定浓度时还对人类健康造成威胁。为研究中原地区环境空气中VOCs污染状况,探查VOCs对人群健康产生的风险,以中原地区核心城市-郑州为代表,于2012年─2013年间,在郑州市区内布点,以苏玛罐采样/气相色谱-质谱法分析测定了VOCs的时空分布,并使用健康风险评价四步法进行健康风险评价。郑州市环境空气中VOCs年均浓度分布特征:以烷烃和芳香烃为主,分别占总量的23.8%和19.5%;年平均质量浓度,芳香烃类为131μg·m-3、烷烃类为118μg·m-3,酮类为84.3μg·m-3、卤代烷烃类为67.8μg·m-3;单体化合物以丙酮(66.2μg·m-3)、乙醇(27.5μ·m-3)、正十一烷(24.4μg·m-3)和甲苯(17.2μg·m-3)质量浓度最高,污染程度在国内居于中等水平。VOCs季均浓度分布特征:夏季高于冬季,但各类化合物在两季的浓度差异较大。VOCs日均浓度变化特征:烷烃类和芳烃类化合物于10:00出现浓度峰值,浓度变化趋势与交通量变化具有相关性。健康风险评价结果为:非致癌风险大于1,会对人群健康造成一定的非致癌危害;苯、四氯化碳、1,2-二氯乙烷、1,1,2-三氯乙烷、六氯丁二烯的致癌指数超过EPA致癌风险值,但未超出OSHA致癌风险。

Volatile organic compounds （VOCs） could cause not only environmental problems such as haze and photochemicalsmog, but also some threats to human health in a certain concentration. To study the VOCs concentration and the risk of healtheffects from VOCs , the temporal and spatial distribution of VOCs were determined by GC/MS with Canister sampling during theperiod of 2012─2013 in Zhengzhou.The four-step evaluation model of health risk assessment （HRA） which was recognizedinternationally was adopted to preliminarily assess the health risks caused by VOCs. The results showed that alkanes and aromatichydrocarbons were the main compositions of VOCs in ambient air in Zhengzhou and the proportion were 23.8% and 19.5%respectively. The annual average concentration of aromatic hydrocarbons was 131 μg·m-3, the annual average concentration ofalkanes was 118 μg·m-3, and the annual average concentration of ketones was 84.3 μg·m-3. The highest annual concentrationcompounds were acetone （66.2 μg·m-3）, alcohol （27.5 μg·m-3）, undecane （24.4 μg·m-3） and toluene （17.2 μg·m-3）. The pollution wasmiddle level in China. The concentration of VOCs in summer was higher than in winter. But the difference of the concentrations ofvarious types of compounds between two seasons was large. The highest daily concentrations of alkanes and aromatic hydrocarbonsappeared at am 10：00 which was correlated with traffic flow. The results of HRA indicated that non-carcinogenic risk indexes ofVOCs were higher than 1. Volatile pollutants would cause non-carcinogenic health hazard to exposed population.The cancer riskindex exposed to benzene, carbon tetrachloride, 1,2-dichloroethane, 1,1,2-trichloroethane and hexachlorobutadiene was higher thanthe suggested value of USEPA which was not higher than OSHA. It indicated that the exposure might cause potential harm tohuman health.