Abstract
AbstractHigh abundance and strong light absorption of atmospheric brown carbon (BrC) have been reported in East Asia, especially in northern China. However, the molecular‐level understanding of BrC chromophores in this area is still limited and quite challenging. In this study, elemental composition of individual BrC chromophores was first investigated in the megacity of Beijing, China, using a powerful platform for the characterization of BrC chromophores, with combination of high‐performance liquid chromatography coupled to a UV/Vis absorbance detector and a time‐of‐flight mass spectrometer with an electrospray ionization source. The results from this study showed that S‐containing compounds (e.g., CHOS and CHONS) significantly increased in highly polluted days compared to lightly polluted days, probably due to increased emissions from sources such as coal combustion and favorable conditions for organosulfates formation. It was found that CHON and CHO compounds were the most abundant water‐soluble organic compounds in Beijing especially during the wintertime. Nitroaromatic compounds were the major water‐soluble BrC chromophores, with three major BrC chromophores (e.g., C6H5NO3, C7H7NO4, and C6H5NO4) found under all conditions, while other specific BrC chromophores with CHON‐ and CHO‐containing elemental formulas identified and varied in different seasons and pollution conditions. Overall, the water‐soluble BrC chromophores identified in this study explained about 2%–18% of the bulk BrC absorbance over the wavelength range of 300–400 nm. In‐depth studies on exploring more BrC chromophores as well as their chemical structures, related sources, and formation mechanisms should be conducted in the future.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call