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五氧化二氮（N_2O_5）非均相摄取系数的定量和参数化

ISSN号：1005-281X
期刊名称：《化学进展》
时间：0
分类：O613.61[理学—无机化学;理学—化学]
作者机构：北京大学环境科学与工程学院环境模拟与污染控制国家重点实验室,北京100871
相关基金：国家自然科学基金项目（No.41375124,91544225,21190052,41121004）; 中科院先导专项（No.XDB05010500）; 国家重点实验室自由探索基金课题（No.13Z02ESPCP）资助

关键词：五氧化二氮(N2O5), 气溶胶, 非均相反应, 摄取系数, 参数化, dinitrogen pentoxide（N2O5）, aerosol, heterogeneous reaction, uptake coefficient, parameterization

中文摘要：

颗粒物污染是我国超大城市地区面临的主要污染问题,大气化学受到非均相反应的强烈影响。N_2O_5非均相反应过程的定量描述对厘清我国超大城市地区夜间大气氧化性、区域NO_x收支、臭氧生成等问题具有重要意义。本文从反应机理、摄取系数测量技术和不同气溶胶基体测量结果等方面系统总结了N_2O_5非均相反应动力学研究进展。N_2O_5非均相摄取是典型的反应性摄取过程,是气溶胶流动管测量系统的理想应用对象。实验室动力学研究从硫酸盐等模型颗粒物出发,结合外场观测获取的颗粒物信息,模拟使用的颗粒物越来越接近实际大气条件。N_2O_5在不同颗粒物表面摄取系数在0.0010.2之间,其变化范围超过两个数量级,主要受到环境温度、湿度、颗粒物组分中NO_3-、Cl-、SO_4（2-）、含水量、有机物、颗粒物混合状态和相态等因素影响;颗粒物中H_2O、Cl-、SO_4（2-）的浓度升高会提高非均相摄取速率,而NO_3-、有机物则会对摄取过程产生抑制作用。欧美地区外场观测研究表明这些影响因素并不是线性叠加的,而是存在非常复杂的相互作用,基于实验室测量结果开发的参数化公式不能很好地拟合观测结果。由于N_2O_5和颗粒物的高值区共存于污染城市地区,下一步研究需要在包括我国超大城市地区在内的典型城市大气条件下开展更多的外场实测研究和建立更准确的参数化公式。

英文摘要：

Particulate pollution is a major air pollution problem in Chinese mega-cities. Under such conditions,the atmospheric gas-phase chemistry is strongly influenced by heterogeneous reactions,of which to quantify the heterogeneous reaction processes of N_2O_5 is essential for the understanding of the nighttime oxidation capacity,regional NO_x budget,photochemical ozone prodution,etc. In this paper,w e extensively review the research progress of the N_2O_5 heterogeneous reaction processes such as its reaction mechanism,measurement techniques of the corresponding uptake coefficient（ γ_（N_2O_5）） and the measurement results on different aerosol substrates. The heterogeneous reaction processes of N_2O_5 is a typical reactive uptake process which can be ideally studied by theaerosol flow tube system. The corresponding laboratory kinetic studies are started from model aerosols（ sulfate）,and evolved to be more realistic aerosols according to the accumulated know ledges on the aerosol properties obtained in field studies. It is found that the γN_2O_5varied from 0. 001 to 0.2 on different aerosol substrates,more than two orders of magnitude. The variation is influenced by the ambient temperature,relative humidity,mixing state,phase state,aerosol chemical compositions like NO3-,Cl-,SO_4（2-）,liquid water content（ LWC）,organics,etc.,of which the uptake coefficient is higher with higher LWC,Cl-,SO_4（2-） w hile low er with higher NO3- and organics. The avaiable field studies in the United States and Europe show ed that,to describe γN_2O_5,these impact factors can＇t be independently expressed; and the dependence seems to be very complicated and cross correlated. Therefore the state of art parameterization methods of γN_2O_5developed from lab kinetic studies are still not able to describe the field observations. Since high aerosol loading and high N_2O_5 are alw ays co-located at urban aeras, more field observations and sucessful parameterization of γN_2O_5is proposed to be conducted in typical urban con