Vertical distribution of PM2.5 and interactions with the atmospheric boundary layer during the development stage of a heavy haze pollution event

Cheng Liu; Jianping Huang; Yongwei Wang; Xinyu Tao; Cheng Hu; Lichen Deng; Jiaping Xu; Hong-Wei Xiao; Li Luo; Hua-Yun Xiao; Wei Xiao

doi:10.1016/j.scitotenv.2019.135329

Vertical distribution of PM_2.5 and interactions with the atmospheric boundary layer during the development stage of a heavy haze pollution event

Sci Total Environ. 2020 Feb 20:704:135329. doi: 10.1016/j.scitotenv.2019.135329. Epub 2019 Nov 22.

Authors

Cheng Liu¹, Jianping Huang², Yongwei Wang³, Xinyu Tao³, Cheng Hu⁴, Lichen Deng⁵, Jiaping Xu⁶, Hong-Wei Xiao¹, Li Luo¹, Hua-Yun Xiao¹, Wei Xiao³

Affiliations

¹ Jiangxi Province Key Laboratory of the Causes and Control of Atmospheric Pollution/School of Water Resources and Environmental Engineering, East China University of Technology, Nanchang 330013, China.
² Yale-NUIST Center on Atmospheric Environment, International Joint Laboratory on Climate and Environment Change (ILCEC), Nanjing University of Information Science & Technology, Nanjing 210044, China. Electronic address: jianping.huang@noaa.gov.
³ Yale-NUIST Center on Atmospheric Environment, International Joint Laboratory on Climate and Environment Change (ILCEC), Nanjing University of Information Science & Technology, Nanjing 210044, China.
⁴ College of Biology and the Environment, Joint Center for Sstainable Forestry in Southern China, Nanjing Forestry University, Nanjing 210037, China.
⁵ Ecological Meteorology Center, Jiangxi Meteorological Bureau, Nanchang 330096, China.
⁶ Key Laboratory of Transportation Meteorology, China Meteorological Administration, Nanjing 210009, China.

PMID: 31831235
DOI: 10.1016/j.scitotenv.2019.135329

Abstract

Vertical profiles of PM_2.5 (i.e., particulate matter with an aerodynamic diameter of 2.5 µm or less) and meteorological variables (e.g., potential temperature, specific humidity) are crucial to understand formation mechanism including accumulation and dispersion process of PM_2.5, as well as interactions between aerosols and the atmospheric boundary layer (ABL). In this study, vertical distributions of PM_2.5 are characterized through comprehensive analyses of vertical profiles measured by unmanned aerial vehicle (UAV), Micro Pulse LiDAR, and other surface observational data of a heavy aerosol pollution episode occurring on December 22-25, 2017 in Nanjing, China. Results show that PM_2.5 profiles are characterized by a clear three-layer structure with near constant within the mixed layer, a transition layer with a large local gradient in the entrainment zone, and a layer with low concentration and small gradient in the free atmosphere, which shows a large similarity to that of specific humidity. The accumulation of aerosols is found near top of the ABL with the largest increase rate. Vertical distributions of PM_2.5 and their evolution are largely constrained by the ABL thermodynamics during daytime, but show much less dependence on the ABL evolution at nighttime. PM_2.5 provides an important feedback on the nocturnal boundary layer (NBL) leading to significant modification of vertical distributions of potential temperature and water vapor. Moreover, this study suggests that the current boundary layer parameterization scheme needs refinement with aerosol radiative effect included to further improve the ABL height (ABLH) and air quality predictions.

Keywords: Aerosol pollution; Atmospheric boundary layer height (ABLH); PM(2.5); Unmanned aerial vehicle (UAV); Vertical profiles.