基于大气氡监测量化表征区域大气稳定度对灰霾影响的研究

Sever haze events are frequently occurred in major urban agglomerations in China currently, disserve environment and human health. Characteristics of boundary layer mixing evidently influence haze formation and evolution,which should be quantified. Radon (222Rn) is radioactive and inert, which can be used as a tracer of atmospheric boundary layer mixing. The measurement of radon will be applied to study the effects of atmospheric stability on haze formation and evaluation in the proposed project. The long-term monitoring data of haze and meteorological, radon visibility, PM2.5 and gas phase pollutants including SO2, NOx, NO2, O3 from Beijing and Yangtze area will be analyzed. The observation of ground surface and sounding data will also be obtained. The variation profile of atmospheric boundary layer mixing, formation and evaluation of haze will be characterized based on the synthetically data analysis. The project will also demonstrate a method to establish the radon-based atmospheric stability classification scheme, which will serve for analysis of air pollution and haze classification based on the scheme, and quantitatively study the effects of atmospheric stability on haze formation and the effects of boundary layer mixing on air quality, in order to benefit better assessment of the effectiveness of emission reduction measures.

灰霾是我国主要的城市群频发的灾害性大气污染，严重危害环境和人体健康。边界层混合特征对灰霾污染形成演化的明显影响需要定量化表征。氡具有放射性，化学性质稳定，可作为大气边界层混合的示踪剂。本项目将进行大气氡监测，利用北京地区和长三角地区长期的气象和霾监测数据，及大气颗粒物氡、能见度、PM2.5浓度、气态污染物（SO2、NOx、NO2、O3）等的监测，结合地面气象和探空观测资料，对大气边界层混合变化特征和灰霾天气特征进行表征。建立基于氡监测的大气稳定度分类方法，利用该方法对污染物浓度等级和灰霾天气类型进行分析，定量研究大气稳定度对灰霾形成的影响，定量评估边界层混合对空气质量的影响和贡献，有利于科学评估减排措施的有效性。

大气混合状态对污染物浓度及公众空气污染暴露水平起着决定性的作用。如何量化评价大气混合状态变化对污染物浓度变化的影响极其对排污减排措施效果的评价显得尤为重要。本项目研究利用SM200“稳定度监测仪”进行大气氡观测，该测量数值间接反映了大气混合状态，可用于评估和预测空气质量。本项目在长三角地区月在金华市和北京地区进行了连续的大气氡观测，积累了大量大气氡的连续观测数据。结合大气污染物数据监测，气象监测数据和基于氡的稳定度指数分析大气边界层混合对污染天气形成演变的影响，建立了基于氡观测的改进的稳定度分类方法，并且应用大气自清洁能力指数（ASI）并对稳定度方案进行评估，结果证实大气氡测量值可靠地代表了大气混合状态。本方法可以分析城市和区域气象变化对空气污染物及温室气体浓度变化对影响，应用于评价污染和温室气体控制措施的效果。