Photodegradation of atmospheric chromophores: changes in oxidation state and photochemical reactivity.

Citation metadata

Date: Aug. 4, 2021
From: Atmospheric Chemistry and Physics(Vol. 21, Issue 15)
Publisher: Copernicus GmbH
Document Type: Brief article
Length: 258 words

Document controls

Main content

Abstract :

Atmospheric chromophoric organic matter (COM) plays a fundamental role in photochemistry and aerosol aging. However, the effects of photodegradation on chemical components and photochemical reactivity of COM remain unresolved. Here, we report the potential effects of photodegradation on carbon contents, optical properties, fluorophore components and photochemical reactivity in aerosol. After 7 d of photodegradation, fluorescent intensity and the absorption coefficient of COM decrease by 71.4 % and 32.0 %, respectively. Photodegradation makes a difference to the chemical component of chromophore and the degree of aerosol aging. Low-oxidation humic-like substance (HULIS) is converted into high-oxidation HULIS due to photooxidation. Photodegradation also changes the photochemical reactivity. The generation of triplet-state COM (.sup.3 COM.sup.*) decreases slightly in ambient particulate matter (ambient PM) but increases in primary organic aerosol (POA) following photodegradation. The results highlight that the opposite effect of photodegradation on photochemical reactivity in POA and ambient PM. However, the generation of singlet-oxygen (.sup.1 O.sub.2) decreases obviously in POA and ambient PM, which could be attributed to photodegradation of precursors of .sup.1 O.sub.2 . The combination of optical property, chemical component and reactive oxygen species has an important impact on the air quality. The new insights on COM photodegradation in aerosol reinforce the importance of studying dissolved organic matter (DOM) related with the photochemistry and aerosol aging.

Source Citation

Source Citation   

Gale Document Number: GALE|A670654677