合肥秋季气溶胶光学特性及来源分析

doi:10.3964/j.issn.1000-0593(2021)10-3014-07

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Abstract Aerosols directly disturbs the earth’s radiation budget and climate by absorbing and scattering solar radiation, indirectly affecting the formation of cloud condensation nuclei, and further changing the optical properties. A field study was carried out using an aethelometer and nephelometer from 5 November to 10 December 2019 in Hefei. Based on the meteorological data, diurnal variation and wind dependence of the optical properties of aerosols were analyzed. The average PM_2.5, aerosol scattering coefficient (σ_sp), absorption coefficient (σ_ap) in autumn in Hefei were (43±25) μg·m^-3, (238.70±161.52) Mm^-1, and (32.04±17.01) Mm^-1, respectively, and the trend of time variation of σ_sp and σ_ap was consistent with PM_2.5. The contents of PM_2.5, σ_sp, and σ_ap have significant double-peak daily variation characteristics, peaking at 8:00—10:00 and 20:00—21:00, which was mainly related to traffic emissions and meteorological conditions.The wind dependence of aerosol optical properties in Hefei mainly reflects that the weather conditions of low temperature, high humidity and low wind are conducive to the accumulation and formation of pollutants, but the higher wind speed is also easy to transport pollutants around. The σ_ap and σ_sp were mainly affected by the pollution air mass in the northwest wind direction. Based on the HYSPLIT backward trajectory model, the spatial characteristics of different transport pathways were analyzed by cluster analysis, and the potential source contribution method (PSCF) and concentration weight trajectory method (CWT) were used to investigate the potential source area distribution of Hefei. The results showed that the polluted air masses mainly originated from the northwest of Hefei. The highest proportion of air masses 1 and 3 were from Inner Mongolia Autonomous Region and Xinjiang Uygur Autonomous Region. Air mass 2, which contributes more to the scattering coefficient, comes from Baoji City, Shaanxi Province, and air mass 6, which originates from Inner Mongolia, passes through Shanxi, Shandong and Jiangsu Provinces, and arrives at Hefei from the southeast of Anhui Province, carrying more pollutants. PSCF larger value was mainly distributed in the northwest and southwest of Hefei. The high CWT values in autumn in Hefei were mainly distributed in northeast Henan Province, southwest Shandong Province and North Anhui Province. In particular, Jining city in Shandong Province and Shangqiu city in Henan Province are the potential sources of air quality in Hefei.

Key words：Aerosol; Wind dependence; Scattering coefficient; Hefei; Potential source region

Received: 2020-08-04 Accepted: 2020-12-29

ZTFLH:

O433.1

Corresponding Authors: LIU Hao-ran E-mail: hrl@ahu.edu.cn

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https://www.gpxygpfx.com/EN/10.3964/j.issn.1000-0593(2021)10-3014-07 OR https://www.gpxygpfx.com/EN/Y2021/V41/I10/3014