Institute of Physical Science and Information Technology, Anhui University, Hefei 230601, China.
Key Lab of Environmental Optics and Technology, Anhui Institute of Optics and Fine Mechanics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China.
J Environ Sci (China). 2022 Jan;111:75-83. doi: 10.1016/j.jes.2021.01.005. Epub 2021 Mar 19.
New particle formation (NPF) events are an increasingly interesting topic in air quality and climate science. In this study, the particle number size distributions, and the frequency of NPF events over Hefei were investigated from November 2018 to February 2019. The proportions of the nucleation mode, Aitken mode, and accumulation mode were 24.59%, 53.10%, and 22.30%, respectively, which indicates the presence of abundant ultrafine particles in Hefei. Forty-six NPF events occurred during the observation days, accounting for 41.82% of the entire observation period. Moreover, the favorable meteorological conditions, potential precursor gases, and PM range of the NPF events were analyzed. Compared to non-NPF days, the NPF events preferentially occurred on days with lower relative humidity, higher wind speeds, and higher temperatures. When the PM was 15-20, 70-80, and 105-115 μg/m, the frequency of the NPF events was higher. Nucleation mode particles were positively related to atmospheric oxidation indicated by ozone when PM ranged from 15 to 20 μg/m, and related to gaseous precursors like SO and NO when PM was located at 70-80 and 105-115 μg/m. On pollution days, NPF events did not directly contribute to the increase in the PM in the daytime, however, NPF events would occur during the night and the growth of particulate matter contributes to the nighttime PM contents. This could lead to pollution that lasted into the next day. These findings are significant to the improvement of our understanding of the effects of aerosols on air quality.
新粒子形成（NPF）事件是空气质量和气候科学中一个日益引人关注的话题。本研究于 2018 年 11 月至 2019 年 2 月期间在合肥开展，分析了大气颗粒物数浓度粒径分布和 NPF 事件发生的频率。成核模态、爱根核模态和积聚模态的比例分别为 24.59%、53.10%和 22.30%，表明合肥存在丰富的超细颗粒物。观测期间共发生 46 次 NPF 事件，占总观测天数的 41.82%。此外，还分析了 NPF 事件的有利气象条件、潜在前体物和 PM 范围。与非 NPF 日相比，NPF 事件更倾向于发生在相对湿度较低、风速较高和温度较高的日子。当 PM 为 15-20、70-80 和 105-115μg/m 时，NPF 事件的频率更高。当 PM 为 15-20μg/m 时，核模态粒子与臭氧等大气氧化剂呈正相关；当 PM 为 70-80 和 105-115μg/m 时，与 SO 和 NO 等气态前体物呈正相关。在污染日，NPF 事件并没有直接导致 PM 在白天增加，但会在夜间发生，颗粒物的增长导致夜间 PM 含量增加，从而导致污染持续到第二天。这些发现对提高我们对气溶胶对空气质量影响的认识具有重要意义。
