Highly time-resolved chemical characterization and implications of regional transport for submicron aerosols in the North China Plain
Highly time-resolved chemical characterization and implications of regional transport for submicron aerosols in the North China Plain
复制标题
华北平原亚微米气溶胶的高度时间分辨化学特征及其区域传输的影响
DOI：
10.1016/j.scitotenv.2019.135803
复制
发表时间：
2020
影响因子：
9.8
通讯作者：
Wang Yuesi
中科院分区：
文献类型：
--
作者：
Li Jiayun;Liu Zirui;Cao Liming;Gao Wenkang;Yan Yingchao;Mao Jia;Zhang Xinghua;He Lingyan;Xin Jinyuan;Tang Guiqian;Ji Dongsheng;Hu Bo;Wang Lili;Wang Yonghong;Dai Lindong;Zhao D;an;Du Wupeng;Wang Yuesi
为研究华北地区亚微米气溶胶的区域输送和形成机制，于2018年11月至2019年1月首次利用气溶胶质谱仪对北京市区和华北地区本底区的非难降解亚微米气溶胶（NR-PM 1）化学成分进行了同步联合观测。在观测期间，北京和XL的PM 1平均质量浓度分别为26.6 ± 31.7和16.0 ± 18.7 μg m− 3。XL的气溶胶组成显示出有机气溶胶的贡献较低（33%对43%）和硝酸盐（35%对30%），铵（16%对13%）和氯（2%对1%）比在BJ更高的分数。此外，在XL中还观察到二次有机气溶胶（SOA）的贡献较高，表明背景区域的一次排放量较低，氧化程度较高。硝酸盐显示出显着增强的贡献与BJ和XL的气溶胶污染的加剧，这是完全中和过量的铵在两个站点，这表明丰富的氨排放在NCP有利于硝酸盐形成在区域尺度上。此外，XL中较高比例的硝酸盐可归因于背景大气的更中性和更高的氧化能力。非均相水反应在硫酸盐和SOA的形成中起着重要作用，并且在北京更有效，这可以归因于城市站点较高的气溶胶表面积。西北地区的区域输送对灰霾天气的形成有重要影响。除了输送污染物的入侵外，大量水汽伴随气团向下风向背景区输送，进一步加强了局地二次转化，扩大了华北平原灰霾污染的区域范围。
To investigate the regional transport and formation mechanisms of submicron aerosols in the North China Plan (NCP), for the first time, we conducted simultaneous combined observations of the non-refractory submicron aerosols (NR-PM1) chemical compositions using aerosol mass spectrometer at urban Beijing (BJ) and at regional background area of the NCP (XL), from November 2018 to January 2019. During the observation period, average mass concentrations of PM1in BJ and XL were 26.6 ± 31.7 and 16.0 ± 18.7 μg m−3respectively. The aerosol composition in XL showed a lower contribution of organic aerosol (33% vs. 43%) and higher fractions of nitrate (35% vs. 30%), ammonium (16% vs. 13%), and chlorine (2% vs. 1%) than in BJ. Additionally, a higher contribution of secondary organic aerosol (SOA) was also observed in XL, suggesting low primary emissions and highly oxidized OA in the background area. Nitrate displayed a significantly enhanced contribution with the aggravation of aerosol pollution in both BJ and XL, which was completely neutralized by excess ammonium at both sites, suggesting that the abundant ammonia emissions in the NCP favor nitrate formation on a regional scale. In addition, a higher proportion of nitrate in XL can be attributed to the more neutral and higher oxidation capacity of the background atmosphere. Heterogeneous aqueous reaction plays an important role in sulfate and SOA formation, and is more efficient in BJ which can be attributed to the higher aerosol surface areas at urban site. Regional transport from the southwestern regions of NCP showed a significant impact on the formation of haze episodes. Beside the invasion of transported pollutants, the abundant water vapor associated with the air mass to the downwind background area further enhanced local secondary transformation and expanded the regional scope of the haze pollution in the NCP.