Cao Jun, Xie Jia-Li, Sun Juan, Li Jin-Wen, Xu Zheng, Hua Chen-Jie, Zhang Yu-Sheng, Song Bo-Ying, Liu Yong-Chun
Jiangsu Environmental Monitoring Centre, Nanjing 210019, China.
Aerosol and Haze Laboratory, Advanced Innovation Center for Soft Matter Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, China.
Huan Jing Ke Xue. 2023 Oct 8;44(10):5356-5369. doi: 10.13227/j.hjkx.202210270.
Recently, the contribution of inorganic salts (nitrates in particular) to the mass concentration of particulate matter with an aerodynamic diameter of less than 2.5 μm (PM) has been increasing across China. However, it is urgent to understand how the increased inorganic salts affect the crucial properties of PM. Here, we conducted continuous field observations at Zhenjiang Ecology and Environment Protection Bureau from January 1 to December 31, 2021. The mass concentrations of ammonium sulfate[(NH)SO] and ammonium nitrate (NHNO) were calculated using different methods. The contributions of (NH)SO and NHNO to the extinction coefficient, hygroscopic growth, and acidity of PM were discussed in detail. Our results demonstrated that the mean mass concentrations of (NH)SO and NHNO during the study period were (6.5±4.5) and (15.0±13.3) μg·m, which contributed (20.5±18.2)% and (34.5±18.4)% to the mass concentration of PM, respectively. The total extinction coefficient of PM was (224.5±194.2) Mm, in which NHNO was the largest contributor[(40.1±20.9)%] followed by (NH)SO[(19.1±10.8)%]. (NH)SO and NHNO were also the dominant contributors to the hygroscopic growth of PM. In particular, NHNOcontributed from (53.8±13.4)% to (61.6±14.6)% to the aerosol water content of PM under pollution conditions. Thus, NHNO was a key air pollutant to be targeted for further improving the visibility and air quality in Zhenjiang in the future. However, the reduction in the precursors of NHNO would lead to an increase in aerosol acidity, particularly in the spring and winter seasons. Our results help us understand the evolution of air quality and the related impacts and also provide important information on air quality improvement in Zhenjiang in the future.
近年来，在中国，无机盐（尤其是硝酸盐）对空气动力学直径小于2.5微米的颗粒物（PM）质量浓度的贡献一直在增加。然而，迫切需要了解增加的无机盐如何影响PM的关键特性。在此，我们于2021年1月1日至12月31日在镇江市生态环境保护局进行了连续的实地观测。采用不同方法计算了硫酸铵[(NH₄)₂SO₄]和硝酸铵（NH₄NO₃）的质量浓度。详细讨论了(NH₄)₂SO₄和NH₄NO₃对PM消光系数、吸湿增长和酸度的贡献。我们的结果表明，研究期间(NH₄)₂SO₄和NH₄NO₃的平均质量浓度分别为(6.5±4.5)和(15.0±13.3)微克·立方米，分别占PM质量浓度的(20.5±18.2)%和(34.5±18.4)%。PM的总消光系数为(224.5±194.2)Mm⁻¹，其中NH₄NO₃贡献最大[(40.1±20.9)%]，其次是(NH₄)₂SO₄[(19.1±10.8)%]。(NH₄)₂SO₄和NH₄NO₃也是PM吸湿增长的主要贡献者。特别是，在污染条件下，NH₄NO₃对PM气溶胶含水量的贡献为(53.8±13.4)%至(61.6±14.6)%。因此，NH₄NO₃是未来进一步改善镇江能见度和空气质量的关键空气污染物。然而，NH₄NO₃前体的减少将导致气溶胶酸度增加，尤其是在春季和冬季。我们的结果有助于我们了解空气质量演变及其相关影响，也为未来镇江空气质量改善提供重要信息。
