Abstract
Atmospheric aerosols contain organic matter that can form triplet state (3C*) excited by sunlight, which plays a critical role in the aging process of aerosols. In order to understand the triplet state reaction mechanism of complex aerosol components, the formation characteristics of 3C* in the aerosol components with different polarity, i.e., the highly polar water-soluble matter (HP-WSM), humic-like substances (HULIS) and methanol-soluble matter (MSM) were investigated. The coupling effect of generation of 3C* and reactive oxygen species (ROS) between different aerosol components was also examined. The results show that the 3C* generation characteristics is strongly dependent on the polarity of these components. HULIS has the strongest generation ability of 3C*, and the MSM contribute the most to the total generation of 3C*. It is found that the high-energy triplet states (ET ≥ 250 kJ mol−1) of HULIS and HP-WSM components account for up to 80 %. These 3C* has an important contribution to the photochemically generation of ROS, and the generated ROS of different components are also different, which is determined by the chromophore composition of complex organic matter. Tyrosine-like chromophore is the main substance leading to the formation of water-soluble 3C*, whilethe highly oxidized HULIS chromophore plays a leading role in the water-insoluble component. This study also found that there is a coupling effect between HP-WSM and HULIS on 3C* and ROS generation. The 3C* generation rate increases by about 40 % after mixing, but the generation of 1O2 is severely reduced. Overall, this study provides deep insights into the generation characteristics of the triplet state of atmospheric aerosols.
Highlights
Atmospheric photochemical processes play an important role in the formation and aging of aerosols (Atkinson, 2000; Derwent et al, 1998; Lim et al, 2005; Ervens et al, 2011; Blando and Turpin, 2000)
In order to explore the formation characteristics and mechanism of triplet in atmospheric aerosols, this study separated complex aerosol components according to polarity, and obtained highly polar water soluble (HP-WSM), humic-like substances (HULIS) and methanol soluble components (MSM, representative of water-insoluble organic matter)
Organic carbon is the main precursor for the formation of triplet states in aerosols, and the composition of organic carbon is different between components of different polarities
Summary
Atmospheric photochemical processes play an important role in the formation and aging of aerosols (Atkinson, 2000; Derwent et al, 1998; Lim et al, 2005; Ervens et al, 2011; Blando and Turpin, 2000). Atmospheric chromophores are organic substances with light-absorbing properties in the atmospheric environment, which are the precursors of 3C* in aerosols. Because the atmospheric chromophore is not a single substance, but a complex organic mixture, this increases the difficulty of studying the generation mechanism of 3C* in actual atmospheric environment. Due to the large differences in the sources and chemical processes of organic matter in the atmospheric environment and the water environment, the research conclusions on the 3C* generation characteristics of water bodies may not be suitable for atmospheric aerosols. In order to explore the formation characteristics and mechanism of triplet in atmospheric aerosols, this study separated complex aerosol components according to polarity, and obtained highly polar water soluble (HP-WSM), humic-like substances (HULIS) and methanol soluble components (MSM, representative of water-insoluble organic matter). This study confirmed the coupling effect of generation of 3C* and ROS between different aerosol components (HP-WSM and HULIS)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
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 callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
