Wu Gengchen, Wang Hao, Zhang Chengliang, Gong Daocheng, Liu Xiaoting, Ristovski Zoran, Wang Boguang
Institute for Environmental and Climate Research, Jinan University, Guangzhou 511443, China; Guangdong Provincial Observation and Research Station for Atmospheric Environment and Carbon Neutrality in Nanling Forests, China.
Institute for Environmental and Climate Research, Jinan University, Guangzhou 511443, China; Guangdong Provincial Observation and Research Station for Atmospheric Environment and Carbon Neutrality in Nanling Forests, China; JNU-QUT Joint Laboratory for Air Quality Science and Management, Jinan University, Guangzhou 511443, China.
Sci Total Environ. 2023 Dec 10;903:166192. doi: 10.1016/j.scitotenv.2023.166192. Epub 2023 Aug 9.
Aerosol acidity plays a crucial role in atmospheric physicochemical processes, climate change and human health, particularly in the formation of secondary organic aerosols (SOA). However, understanding the characteristics and driving factors of aerosol acidity in background mountains has been limited. In this study, we conducted intensive field measurements in the Nanling mountains during the dry and wet seasons to analyze aerosol pH characteristics and their driving factors using sensitivity tests. The mean aerosol pH in the background mountains was found to be 2.68 ± 0.55, with values ranging from 0.38 to 4.44, significantly lower than predicted values in northern China. Sensitivity tests revealed that aerosol acidity in the background atmosphere was more responsive to dominant chemical species (T-NH (= NH + NH) and SO) rather than relative humidity and temperature. Additionally, we observed that sulfate and ammonium, transported occasionally by dryer northern air masses, had a substantial impact on decreasing aerosol pH at the site. Similar to the southeastern United States, NH/NH also dominated the total buffer capacity of aerosol acidity in the Nanling mountains. The strong aerosol acidity in this area is expected to have adverse effects on regional air quality and climate by enhancing SOA formation and regulating the dry deposition of inorganic reactive nitrogen.
气溶胶酸度在大气物理化学过程、气候变化和人类健康中起着至关重要的作用，特别是在二次有机气溶胶（SOA）的形成过程中。然而，对背景山区气溶胶酸度的特征和驱动因素的了解一直有限。在本研究中，我们在南岭山区的旱季和雨季进行了密集的实地测量，通过敏感性测试分析气溶胶pH值特征及其驱动因素。发现背景山区气溶胶的平均pH值为2.68±0.55，范围为0.38至4.44，显著低于中国北方的预测值。敏感性测试表明，背景大气中的气溶胶酸度对主要化学物质（T-NH（=NH+NH）和SO）的响应比对相对湿度和温度的响应更大。此外，我们观察到偶尔由北方干燥气团输送来的硫酸盐和铵对该地点气溶胶pH值的降低有很大影响。与美国东南部类似，NH/NH在南岭山区气溶胶酸度的总缓冲能力中也占主导地位。预计该地区强烈的气溶胶酸度将通过增强SOA的形成和调节无机活性氮的干沉降，对区域空气质量和气候产生不利影响。
