A New Method for Eliminating Dust Effects When Quantifying the Light Absorption Properties of Brown Carbon

Abstract

Accurate quantification of the absorption properties of brown carbon (BrC) aerosols is crucial to assess the Earth-atmosphere radiative impacts of BrC. However, the BrC absorption properties were often misestimated in field observations, due to neglecting the contribution of dust absorption. This study solved this problem by coupling a method for calculating the dust concentration into the traditional model for quantifying BrC absorption. The results show that dust absorption was up to 16.8% of the sum of BrC and dust absorption in northwestern China. The potential contribution of dust to the sum of BrC and dust absorption was significantly higher in the Asia-located studies (0.4%–16.8%) than in the Americas-located (<1.2%) and Europe-located (<2.3%) studies. This work underscores the necessity of eliminating the negative effect of dust in BrC quantitative model. It prompts us to revisit the BrC absorption properties resolved by previous studies, especially in dust-influenced areas such as Asia.