LAPC, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, China.
LAPC, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, China.
Sci Total Environ. 2018 May 1;622-623:1327-1342. doi: 10.1016/j.scitotenv.2017.12.041. Epub 2017 Dec 13.
Currently, many challenges are faced in simulating ozone(O), sulfate(SO), and nitrate(NO) concentrations over East Asia, particularly the overestimation of surface O and NO concentrations and underestimation of the SO concentration during haze episodes. In this study, we examined the radiative and heterogeneous chemical effects of aerosols by incorporating recently reported mechanisms, including self-amplifying SO formation, dinitrogen pentoxide (NO) hydrolysis, and a heterogeneous reaction converting gaseous nitric acid (HNO) to nitric oxide (NO), into a Nested Air Quality Prediction Modeling System. Uptakes by aerosols can be computed through a simple parameterization that is dependent on the aerosol core and shell species, shell thickness, and amount of aerosol liquid water. In this study, a 1-year simulation was conducted for 2013. The updated model successfully reproduced the seasonal and daily observations of O, fine particulate matter, SO, and NO concentrations in East Asia. Our results revealed that heterogeneous reactions reduced more surface O concentrations (10-20 ppbv) in the polluted regions of East China than did perturbations in photolysis frequencies from aerosols, effectively again improving the comparison between simulations and observations. Oxidation of SO by NO on wet aerosols significantly enhanced SO formation, with sulfate covering approximately ~30-60% of total sulfate concentrations in North China Plain during haze days in winter. The uptake of reactive nitrogen species on aerosols effectively reduced NO concentrations and successfully balanced the NO/HNO chemistry in the models. We recommended that larger reductions of gaseous precursors should be considered in China to achieve the national air quality objective. The results show that surface O concentrations over East China will increase if the emission of aerosols is reduced without corresponding reductions in O precursors.
目前，在模拟东亚地区臭氧（O）、硫酸盐（SO）和硝酸盐（NO）浓度方面面临着许多挑战，尤其是在雾霾期间，地表 O 和 NO 浓度被高估，而 SO 浓度被低估。在这项研究中，我们通过将最近报道的机制，包括自增强 SO 形成、五氧化二氮（NO）水解和将气态硝酸（HNO）转化为一氧化氮（NO）的多相反应，纳入嵌套空气质量预测模型系统中，考察了气溶胶的辐射和多相化学效应。气溶胶的吸收可以通过一个简单的参数化来计算，该参数化取决于气溶胶核和壳的种类、壳厚度和气溶胶液态水的量。在这项研究中，我们对 2013 年进行了为期一年的模拟。更新后的模型成功地再现了东亚地区 O、细颗粒物、SO 和 NO 浓度的季节性和日变化观测结果。我们的结果表明，多相反应在东亚污染地区减少了更多的地表 O 浓度（10-20 ppbv），比气溶胶光解频率的变化更有效，从而有效地再次改善了模拟与观测之间的对比。NO 在湿气溶胶上对 SO 的氧化显著增强了 SO 的形成，在冬季华北平原的雾霾日，硫酸盐约占总硫酸盐浓度的 30-60%。氮氧化物在气溶胶上的吸收有效地降低了 NO 浓度，并成功地平衡了模型中的 NO/HNO 化学。我们建议中国应考虑更大幅度地减少气态前体物的排放，以实现国家空气质量目标。结果表明，如果减少气溶胶的排放而没有相应减少 O 前体物的排放，东亚地区的地表 O 浓度将会增加。
