绵阳地区近地面气溶胶中7Be和210Pb分布特征及其对O3的示踪

为了解绵阳地区近地面空气中辐射环境质量状况,掌握其变化趋势,探索近地面气溶胶物质来源及其对近地面O₃浓度示踪意义,对绵阳安州区、江油市、梓潼县和平武县2018年3月至2019年2月气溶胶样品进行详细的γ能谱分析。总体上,⁷Be的活度浓度在春、秋季节较高,而夏季最低,年平均值为1.90～2.13 mBq/m³,与全球内陆、中纬度和低海拔地区分布特征基本一致;²¹⁰Pb的活度浓度全年呈现为“U”型分布特征,年平均值为1.24～1.66 mBq/m³,为全球陆地上²¹⁰Pb活度浓度的相对高值。通过近地面气溶胶中⁷Be、¹⁰Pb和⁷Be/²¹⁰Pb比值与O₃相关性分析及P值检验表明:气溶胶中⁷Be/²¹⁰Pb比值与近地面O₃为非常显著正相关关系,能作为近地面空气中O₃来源的良好示踪指标;绵阳地区梓潼县和平武县近地面空气中O₃来源受大气垂直对流活动影响较大。

Distribution characteristics of 7Be and 210Pb in near surface aerosolsin Mianyang area and their tracing of O3

In order to understand the radiation environmental quality status in the air near the ground in Mianyang,grasp its changing trend,and to explore the source of near surface aerosol and its significance for tracing the concentration of near surface O₃,the aerosol samples were analyzed in detail from Anzhou District,Jiangyou City,Zitong county and Pingwu County of Mianyang city from March 2018 to February 2019.In general,the activity concentration of ⁷Be was higher in spring and autumn,and the lowest level was in summer,with an annual average of 1.90-2.13 mBq/m³,which was basically consistent with the global distribution characteristics of inland,mid latitude and low altitude areas.The annual average of ²¹⁰Pb activity concentration was 1.24-1.66 mBq/m³,which was the relatively high value of ²¹⁰Pb activity concentration on the global land.Through the correlation analysis and P value test of ⁷Be,¹⁰Pb and ⁷Be/²¹⁰Pb ratios in near surface aerosols and O₃,the results show that there is a very significant positive correlation between ⁷Be/²¹⁰Pb ratio and near surface O₃,which can be used as a good tracer for the source of O₃ in the near surface air.The source of O₃ in the near surface air in Zitong and Pingwu counties in Mianyang city is greatly affected by the vertical convection.