大气颗粒物中210Pb和210Po的源解析及其对大气颗粒物滞留时间的示踪

大气颗粒物污染是我国当前面临的重要环境问题之一，对大气颗粒物污染的深入研究，离不开对大气颗粒物滞留时间的准确估算。颗粒活性放射性核素210Pb和210Po是研究大气颗粒物滞留时间的良好示踪剂，但因大气中存在除母体222Rn衰变以外的其他来源的贡献，如表层土壤微小颗粒再悬浮、化石燃料的燃烧等，导致基于210Po/210Pb活度比计算得到的大气颗粒物滞留时间明显偏高。本项目选择粤港澳大湾区城市东莞市作为研究区域，拟利用放射性同位素（210Pb和210Po）和稳定同位素（Pb和Sr同位素）复合示踪技术对东莞市大气颗粒物中的210Pb和210Po进行定量源解析，并基于校正后的210Po/210Pb活度比对东莞市大气颗粒物滞留时间进行准确的估算。项目的实施将加深对大气颗粒物污染及其在大气中滞留产生的累积效应影响的理解，为有关部门制定防治大气颗粒物污染的措施提供科学依据。

Atmospheric aerosols pollution is one of the most important environmental problems in China, and the deep understanding of atmospheric aerosol pollution requires the accurate estimation of the residence time of atmospheric aerosols (RTAA). Particle-reactive radionuclides 210Pb and 210Po are served as ideal natural tracers to study the RTAA, however, there are extra sources for 210Pb and 210Po other than the natural decay from their parent 222Rn in the atmosphere, such as the resuspension of fine particles from surface soil, the burning of fossil fuels, etc., leading to the overestimation of the RTAA by using 210Po/210Pb activity ratios. In the present proposal, one of the Guangdong-Hong Kong-Macao Greater Bay Area cities-Dongguan is chosen as the case study area. Multi-tracing technique by radionuclides (210Pb and 210Po) and stable nuclides (Pb and Sr isotopes) is used for quantitative source apportionment of 210Pb and 210Po in the atmosphere, then the accurate RTAA in Dongguan can be estimated based on the corrected 210Po/210Pb activity ratios. The results of this proposal are expected to be helpful in understanding the atmospheric aerosol pollution and its cumulative effects in the atmosphere, and providing the scientific basis for the concerned government departments to formulate measures to prevent atmospheric aerosol pollution.