Study of aerosol-type characteristics and sources using MAX-DOAS measurement during haze at an urban site in the Fenwei Plain

Atmospheric aerosols range in diameter from a few nanometers to tens of micrometers, and they have direct or indirect effects on atmospheric radiation assessments, global climate change, local air quality and visibility, and human health. In particular, during the high season of haze in autumn and winter, atmospheric aerosols are more conducive to transform and accumulate. In this paper, we used the aerosol optical thickness (AOD) and aerosol profile obtained by MAX-DOAS instrument to study the characteristics of aerosol-type, vertical distribution characteristics of near-surface aerosol, and pollution source analysis. From December 30, 2018, to January 27, 2019, we conducted MAX-DOAS observations on Sanmenxia Environmental Protection Bureau. According to the relative humidity data and ion chromatography data, we analyzed the correlation between AOD and PM_2.5, the result show that aerosols are mainly fine particles, and most of them are nitrates. The near-surface aerosol extinction coefficient obtained by MAX-DOAS was compared with the PM_2.5 and PM₁₀ concentrations measured by unmanned aerial vehicle (UAV). Aerosol particles showed an increasing trend from the ground to 500 m. Combined with the wind field information and the backward trajectory of the air mass during the haze, we found that the continuous heavy pollution was caused by the transportation of polluted air masses in the northeast, along with local industrial emissions and other sources of emissions, which resulted in a wide range and long-term accumulation of pollutants under continuous and steady conditions.