摘要
目的分析兰州市两区2015-2019年大气细颗粒物(fine particulate matter, PM2.5)浓度及其化学成分变化趋势。方法于2015年1月至2019年12月在兰州市选择住宅区代表城关区和工业区代表西固区2个采样点,采集大气细颗粒物样品,检测其质量浓度、金属和类金属元素、水溶性离子及多环芳烃(polycyclic aromatic hydrocarbon, PAHs)的含量。结果 2015-2019年在兰州市城关区和西固区共采集大气细颗粒物样品838份,PM2.5的年均质量浓度和日均浓度超过二级标准的天数均呈现逐年下降趋势(P<0.05)。2015-2019年PM2.5中金属和类金属元素含量较高的是铝、铅、锰和砷;2015-2016年锑、铝、砷、镉、铬、铅、锰和铊的含量高于其他年份(P<0.05),且砷年均浓度分别为7.92、8.63 ng/m3,均超过环境空气质量标准参考浓度限值;2015-2019年铬年均质量浓度远高于环境空气质量标准年均参考浓度限值。在2015-2019年中除了2018年以外,兰州市两区大气PM2.5中PAHs平均浓度最高的均为蒽,苯并[b]荧蒽、茚并[1,2,3-cd]芘年均含量在2015年最高,萘、茐、苊、蒽、菲、荧蒽、芘、苯并[k]荧蒽和苯并[a]芘年均含量在2017年最高,苊烯、■和苯并[g, h,i]苝年均含量在2018年最高(P<0.05);2017-2018年兰州市两区苯并[a]芘平均含量分别为1.16、1.11 ng/m3,均超过环境空气质量标准年均浓度限值。兰州市两区大气PM2.5中水溶性离子Cl-年均浓度呈逐年下降趋势,SO■、NO-3和NH+4在2017-2019年的年均浓度呈逐年下降趋势,两区SO_(4)^(2-)、Cl-均在2015年最高,NO-3、NH+4均在2017年最高(P<0.05)。结论兰州市空气质量有明显改善,但污染问题依然严峻。
OBJECTIVE To analyse the variation of the fine particulate matter(PM2.5) concentration and its chemical composition in two districts of Lanzhou City from 2015 to 2019. METHODS From January 2015 to December 2019, two sampling points, namely residential district(Chengguan District) and industrial district(Xigu District) were selected in Lanzhou City, to collect PM2.5 samples, and the mass concentrations, metals and metalloid elements, water-soluble ions and polycyclic aromatic hydrocarbons(PAHs) contents were determined. RESULTS A total of 838 samples were collected in Chengguan District and Xigu District in Lanzhou City during 2015-2019,the average annual mass concentration and the daily average concentration of the PM2.5 were decreasing year by year(P<0.05).The higher metal content in PM2.5 were Al, Pb, Mn and As during 2015-2019.Sb, Al, As, Cd, Cr, Pb, Mn and Tl element content were higher in 2015 and 2016 than in other years(P<0.05), the average annual concentration of As were 7.92 and 8.63 ng/m3 respectively, which exceeded the reference concentration limit of the ambient air quality standard. The average annual mass concentration of Cr from 2015 to 2019 was much higher than the annual average reference concentration limit of the ambient air quality standard. From 2015 to 2019, except for 2018, the highest average concentration of PAHs in atmospheric PM2.5 in the two districts of Lanzhou City was Ant, B(b)F and I(cd)P mass concentration were highest in 2015, N(a)P,FI,Ace, Phe, Ant, Flu, Pyr, B(k)F and B(a)P mass concentration were highest in 2017, Acy, Chr and B(ghi)P mass concentration were highest in 2018(P<0.05). From 2017 to 2018, the average annual content of B(a)P in the two districts of Lanzhou City were 1.16 and 1.11 ng/m3, respectively, which exceeded the annual average concentration limit of the ambient air quality standard. The concentration of Cl- in PM2.5 in the two districts of Lanzhou City was decreasing year by year, the annual average concentrations of SO■, NO-3 and NH+4 from 2017 to 2019 showed a downward trend year by year.SO■,Cl- of both districts were the highest in 2015, and NO-3,NH+4 were the highest in 2017(P<0.05). CONCLUSION The air quality of Lanzhou City has been improved obviously, but the pollution problem is still serious.
作者
陈瑞
孙建云
魏巧珍
Chen Rui;Sun Jianyun;Wei Qiaozhen(Gansu Provincial Center for Disease Control and Prevention,Lanzhou 730000,China)
出处
《卫生研究》
CAS
CSCD
北大核心
2021年第2期274-278,283,共6页
Journal of Hygiene Research
基金
甘肃省卫生健康行业科研计划项目(No.GSWSKY2020-69)。
关键词
大气
细颗粒物
化学成分
空气质量
atmosphere
fine particulate matter
chemical composition
air quality
