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  • Contribution of Carbonyl Chromophores in Secondary Brown Carbon from Nighttime Oxidation of Unsaturated Heterocyclic Volatile Organic Compounds
Title: Contribution of Carbonyl Chromophores in Secondary Brown Carbon from Nighttime Oxidation of Unsaturated Heterocyclic Volatile Organic Compounds
The light absorption properties of brown carbon (BrC), which are linked to molecular chromophores, may play a significant role in the Earth’s energy budget. While nitroaromatic compounds have been identified as strong chromophores in wildfire-driven BrC, other types of chromophores remain to be investigated. Given the electron-withdrawing nature of carbonyls ubiquitous in the atmosphere, we characterized carbonyl chromophores in BrC samples from the nighttime oxidation of furan and pyrrole derivatives, which are important but understudied precursors of secondary organic aerosols primarily found in wildfire emissions. Various carbonyl chromophores were characterized and quantified in BrC samples, and their ultraviolet–visible spectra were simulated by using time-dependent density functional theory. Our findings suggest that chromophores with carbonyls bonded to nitrogen (i.e., imides and amides) derived from N-containing heterocyclic precursors substantially contribute to BrC light absorption. The quantified N-containing carbonyl chromophores contributed to over 40% of the total light absorption at wavelengths below 350 nm and above 430 nm in pyrrole BrC. The contributions of chromophores to total light absorption differed significantly by wavelength, highlighting their divergent importance in different wavelength ranges. Overall, our findings highlight the significance of carbonyl chromophores in secondary BrC and underscore the need for further investigation.  more » « less
Award ID(s):
1953905
PAR ID:
10553048
Author(s) / Creator(s):
; ; ; ; ;
Publisher / Repository:
American Chemical Society
Date Published:
Journal Name:
Environmental Science & Technology
Volume:
57
Issue:
48
ISSN:
0013-936X
Page Range / eLocation ID:
20085 to 20096
Subject(s) / Keyword(s):
Subjects: Carbon, Carbonyls, Chromophores, Light absorption, Pyrroles Keywords: furan and pyrrole derivatives, secondary organic aerosols, imides and amides, light absorption contribution, wavelength dependency
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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