Investigation of aerosol transport flux structure over Beijing based on lidar observations and the impact of dust transport on air quality

Abstract

The origins, spatial distribution, and diffusion mechanisms of aerosols hold practical guiding significance for regional haze governance. The vertical and horizontal fluxes of aerosols serve as effective parameters for assessing the diffusion efficiency of aerosols, but they are less exploited due to insufficient observations. This study uses polarization lidar to differentiate between the aerosol sources of dust and non-dust and to estimate the mass concentration profiles of each. Combining the wind profiles acquired from Doppler wind lidar, the vertical and horizontal fluxes profiles of two type aerosols are calculated. This approach is designed to account for the influence of local aerosol transport mechanisms on air pollution, enabling a more precise reflection of the internal variations within a particular region. A winter haze event in Beijing from 2–4 November 2023 was analyzed to distinguish the vertical distribution of and mass concentration and fluxes of aerosols brought by dust transported from the northwest monsoon and those from anthropogenic emissions within the North China plain area. Further analysis of different wind zones revealed that the aerosol concentration and fluxes from urban areas (regions with a higher density of anthropogenic sources) can be used to assess the local pollutant diffusion capacity, as well as the influence of vertical turbulence on ground PM10 concentrations. Taking Beijing as an example, this study investigated the diffusion characteristics of urban aerosols, ultimately providing technical means and data references for early warning of urban air pollution and assessment of air pollution control measures.