摘要
自2013年《大气污染防治行动计划》实施以来,我国空气质量持续改善,但京津冀地区细颗粒物浓度仍远高于国家标准,秋冬季重污染天气仍时有发生.近些年,我国科学家在大气污染的立体探测、成因机制和来源解析、气溶胶和边界层相互作用等研究领域取得重要进展,进一步支撑了我国大气污染的科学防治和重污染天气的有效应对,然而我国当前大气污染仍面临诸多科学难题.本文简要概述了我国近些年在大气污染垂直探测方面的一些研究进展,特别是依托于北京325 m气象塔建设的城市边界层理化结构探测平台,详细论述了北京地区不同季节大气气溶胶化学组分的垂直分布特征及其与边界层物理要素的相互作用,同时基于2014年亚太经合组织峰会(APEC)和2015年纪念抗日战争胜利70周年阅兵前后的垂直观测,阐明了大气污染化学组分对区域源排放控制的响应机制.本文还针对大气细颗粒物中的二次无机组分(硝酸盐和硫酸盐)和二次有机气溶胶的生成机制以及极端霾事件的生消机制的最新研究进展进行了评述,并在最后对大气污染监测、二次无机气溶胶生成机制和有机气溶胶的分子组成和物理化学属性(相态、挥发性和氧化态等)等未来研究给出了一些建议.
Air quality in China has been continuously improved since the implementation of ＂Atmospheric Pollution Prevention and Control Action Plan＂ in 2013.However,the mass concentrations of fine particles particularly in Beijing,Tianjin and Hebei are still much higher than the National Ambient Air Quality Standard（35 μg m-3 as an annual average）,and severely polluted events also occur occasionally in autumn and winter seasons.In recent years,Chinese research scientists have made significant progresses in vertical measurements of air pollution,formation mechanisms and source apportionment of atmospheric aerosol,and also the interactions between aerosol and atmospheric boundary layer,which greatly support the scientific prevention and control of atmospheric pollution.Despite this,many questions on atmospheric pollution have not been well addressed yet.This paper first summarizes the recent research progresses in vertical measurements of air pollution in China,in particular,the measurements from the research platform of the Beijing 325 m meteorological tower.In addition to the routine long-term measurements of boundary layer（turbulence,CO2 and H2 O flux） and meteorological parameters（temperature,relative humidity,wind speed and wind direction） at 7 and 15 heights,respectively,this platform can have simultaneous real-time measurements of aerosol particle composition（organics,sulfate,nitrate,ammonium,chloride,and black carbon）,gaseous species（CO,SO2,and O3）,particle number size distributions,and optical properties（extinction and absorption coefficients） at ground level and 260 m,and also the continuously vertical measurements from ground to 260 m using the tower container equipped with specific instruments.Then,the vertical differences of aerosol composition in different seasons in Beijing,and their interactions with boundary layer are discussed.Also,the response of aerosol chemistry to regional source emission control are elucidated based on vertical measurements during the Asia-Pacific Economic Conference（APEC） summit in 2014 and the 70 th anniversary parade in 2015.This paper also reviews the latest research progress on formation mechanisms of secondary inorganic aerosol（nitrate and sulfate） and secondary organic aerosol,and the life cycles of severe haze events in China.In particular,the heterogeneous formation of sulfate during severe haze episodes strongly depends on p H values of aerosol liquid water content.While techniques for direct measurements of aerosol particle p H are essential yet challenging,laboratory experiments are more needed now to prove the hypothesis of sulfate formation mechanisms.Compared with inorganic species,the formation and evolutionary mechanisms of secondary organic aerosol（SOA） are far more complex in polluted environments,and their roles in haze formation need to be better characterized.Finally,this paper lists some future recommendations for air pollution measurements（e.g.,from long-term to vertical measurements in terms of significant emission changes in the near future）,formation mechanism of secondary aerosol,and molecular composition and physical and chemical properties（phase,volatility,oxidation state,etc.） of organic aerosol.
作者
孙业乐
Yele Sun(State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China;University of Chinese Academy of Sciences, Beijing 100049, China;Center for Excellence in Regional Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China)
出处
《科学通报》
EI
CAS
CSCD
北大核心
2018年第14期1374-1389,共16页
Chinese Science Bulletin
基金
国家重点基础研究发展计划(2014CB447900)和国家自然科学基金(91744207)资助
关键词
大气边界层
理化结构
大气污染
二次气溶胶
生成机制
atmospheric boundary layer
physical and chemical structure
air pollution
secondary aerosol
formationmechanisms
