2020—2022年海口市城区大气PM2.5中重(类)金属组成及来源解析

    Composition and source apportionment of heavy metals in atmospheric PM2.5 in urban Haikou, China, 2020—2022

    • 摘要:
      目的 探析海口市主城区大气PM2.5中重(类)金属污染的组成和主要来源。
      方法 于2020—2022年对海口市主城区进行逐月定期(10—16日)采集大气PM2.5样品,每日持续采样时间不少于22 h;利用电感耦合等离子体质谱法(ICP-MS)测量PM2.5样品中25种重(类)金属成分;对PM2.5中检出率较高的16种重(类)金属成分采用正定矩阵因子分解模型(PMF)解析主要污染来源。
      结果 2020—2022年海口市主城区大气PM2.5质量浓度范围4.00~64.00 μg/m3,均数(x±s)为(20.48±12.88)μg/m3、中位数(M)17.00 μg/m3及四分位数间距(IQR)14.25 μg/m3,年度间PM2.5 24小时平均浓度差异不具有统计学意义(χ2=1.24, P>0.05);不同季节PM2.5 24小时平均浓度差异具有统计学意义(χ2=44.86, P < 0.01),PM2.5 24小时平均浓度(均数)高低顺序为冬季>秋季>春季>夏季;16种重(类)金属的质量浓度范围为0.01~1 008.00 ng/m3,质量浓度M值由高到低依次为Fe>Al>Zn>Mn>Pb>Ba>Cu>Sr>Ni>Se>V>As>Sn>Cr>Cd>Li。PMF模型解析结果表明,PM2.5中16种重(类)金属污染主要贡献来源以道路及土壤尘源(49.82%)和交通尾气源(36.96%)为主,次之贡献源有混合燃烧源(9.61%)、建材施工尘源(2.51%)和船舶燃油源(1.10%)。
      结论 2020—2022年海口市大气PM2.5质量浓度均未超过我国《环境空气质量标准》 (GB 3095-2012) 24小时平均浓度二级限值(75 μg/m3)水平,PM2.5中重(类)金属构成主要以Fe、Al、Zn、Mn和Pb元素为主,其主要贡献源是道路及土壤尘源和交通尾气源。

       

      Abstract:
      Objective To explore the composition and main sources of heavy metals pollution in atmospheric PM2.5 in the main urban area of Haikou.
      Methods From 2020 to 2022, the atmospheric PM2.5 in the main urban area of Haikou was regularly monitored month by month, and the atmospheric PM2.5 samples were collected from 10th to 16th days of each month, and the daily sampling time was not less than 22 hours. Twenty-five heavy metals in PM2.5 samples were measured by inductively coupled plasma mass spectrometry (ICP-MS). Main sources of sixteen heavy metals in PM2.5, which have high detection rate in PM2.5 were analyzed by positive matrix factorization model (PMF).
      Results During 2020 to 2022, the median and quartile range of PM2.5 mass concentrations was 17.00 (14.25)μg/m3, mass concentrations of PM2.5 ranged from 4.00 to 64.00 (20.48±12.88)μg/m3, and there was no statistically significance yearly difference in the PM2.5 24-hour average concentrations (χ2=1.24, P>0.05). The PM2.5 24-hour average concentrations had a statistically significant quarterly difference (χ2=44.86, P < 0.01), which was highest in winter, followed by autumn and spring, and lowest in summer. The mass concentrations of the sixteen heavy metals ranged from 0.01-1 008.00 ng/m3, and the medians of mass concentrations in sixteen heavy metals were Fe>Al>Zn>Mn>Pb>Ba>Cu>Sr>Ni>Se>V>As>Sn>Cr>Cd>Li from the highest to the lowest. The analysis results of PMF model showed that the main contribution sources of sixteen heavy metals in the main urban area of Haikou were road and soil dust (49.82%), traffic exhaust (36.96%), mixed combustion (9.61%), construction dust (2.51%), and ship oil combustion (1.10%).
      Conclusion The mass concentrations of atmospheric PM2.5 in Haikou from 2020 to 2022 is lower than the 24-hour average concentration secondary limit value (75 μg/m3) of the Ambient Air Quality Standards (GB 3095-2012). The heavy metals in PM2.5 are mainly Fe, Al, Zn, Mn and Pb. The main contribution sources are road and soil dust sources and traffic exhaust sources.

       

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