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The study on the light absorption of carbonaceous components is a research hotspot in the field of aerosol optical. Size distribution and lensing effect have great influence on the absorption of elemental carbon (EC) and brown carbon (BrC). However, few studies were conducted on the spatial variations of BC and BrC absorption with different size ranges in different regions. In this study, the mass concentration, absorption coefficient and mass absorption efficiency (MAE) of size-resolved carbonaceous components in three functional areas of Nanjing were compared based on offline sampling and experimental analysis. Bimodal and unimodal size distributions were found for EC and BrC mass concentrations at the three sites, respectively. Affected by the emission of diesel vehicles and aggregation condensation, high EC concentration in the size range of 0.56-1 mu m was found at the suburban site. Due to the secondary formation from VOCs, high BrC concentration in the size range of 0.18-0.32 mu m was observed at the industrial site. High EC concentration in the size range of 0.18-0.32 mu m caused by diesel emission was the main reason for the high EC absorption in the regional area. Compared with vehicle emissions, the absorption capacity of secondary BrC was weaker. The variation of MAE values caused by various sources was the key factor leading to BrC absorption, which varied greatly in different regions. This study is helpful to understand the variation of light absorption of carbonaceous component and its source influence in a typical polluted city in the Yangtze River Delta, which provides important data support for the comprehensive evaluation of the role of aerosol light absorption in the change of radiative forcing in different regions.

来源平台：AIR QUALITY ATMOSPHERE AND HEALTH