郑州市冬春季PM_(2.5)中金属元素污染特征、来源及健康风险评估

Pollution Characteristics,Source,and Health Risk Assessment of Metal Elements in PM_(2.5) Between Winter and Spring in Zhengzhou

于2021年1月和4月利用在线金属分析仪对郑州市大气PM_(2.5)中的18种金属元素进行连续测定,分析了元素浓度变化特征;采用富集因子、正定矩阵因子分解法(PMF)和特征雷达图对金属元素进行溯源;采用美国EPA健康风险评价模型评估其健康风险,并通过后向轨迹法和浓度权重轨迹法(CWT)分析了健康风险的潜在源区.结果表明,春季元素浓度较高,Fe、Ca、Si和Al浓度之和分别占冬季和春季总元素浓度的89.8%和87.5%.Cd属于重度富集,受人为污染影响严重.冬季Pb、Se、Zn、Ni、Sb和K以及春季Cr、Ni、Fe、Mn、V、Ba、Ca、K、Si和Al浓度随污染等级的提高而增加.PMF源解析和特征雷达图结果表明,冬春两季金属元素主要来源为工业源、地壳源、机动车源和混合燃烧源,冬季多发生工业源和混合燃烧源污染,春季多发生地壳源污染.冬春两季均存在明显的非致癌风险,冬季健康风险更严重,Mn造成明显的非致癌风险.冬季健康风险主要受郑州及周边城市传输影响和西北方向远距离输送影响,春季健康风险主要受郑州及周边城市影响.

A total of 18 metal elements in ambient PM_(2.5) in Zhengzhou were continuously determined using an online heavy metal observation instrument in January and April,2021,and the changes in element concentrations were analyzed.Metal elements were traced via enrichment factors,positive matrix factorization(PMF),and a characteristic radar chart.The US EPA health risk assessment model was used to assess the health risks of heavy metals,and the backward trajectory method and the concentration-weighted trajectory(CWT)method were used to evaluate the potential source regions of health risks.The results showed that the element concentrations were higher in spring,and the sum of Fe,Ca,Si,and Al concentrations accounted for 89.8%and 87.5%of the total element concentrations in winter and spring,respectively.Cd was enriched significantly,which was related to human activities.The concentrations of Pb,Se,Zn,Ni,Sb,and K in winter and Cr,Ni,Fe,Mn,V,Ba,Ca,K,Si,and Al in spring increased with the increasing pollution level.The results of PMF and the characteristic radar chart showed that the main sources of metal elements in winter and spring were industry,crust,motor vehicles,and mixed combustion,with industry and mixed combustion pollution occurring more often in winter and crust pollution occurring more often in spring.Significant non-carcinogenic risks existed in both winter and spring with more severe health risks in winter,and Mn caused significant non-carcinogenic risks.The health risks in winter were mainly influenced by Zhengzhou and surrounding cities and long-distance transport in the northwest,and the health risks in spring were mainly influenced by Zhengzhou and surrounding cities.