Complexities of Photosensitization in Atmospheric Particles

ACS ES&T Air, Journal Year: 2024, Volume and Issue: 1(11), P. 1333 - 1351

Published: Oct. 10, 2024

Brown carbons (BrCs) play a pivotal role in the light absorption by aerosol particulates exerting positive radiative forcing effect that contributes to global warming. Beyond impacts on balance, some BrCs, as photosensitizers, can generate reactive triplet-state molecules toward various atmospheric upon photoexcitation. The significance of photosensitization has been increasingly recognized, particularly context escalated wildfire incidents emit substantial BrCs. We focus complex discussing current challenges, including (1) diverse reactivities photosensitizer mixture particles, (2) methodologies for investigating processes, (3) driving factors photosensitization, and (4) typical pathways mechanisms photosensitized reactions. Lastly, we advise future research refined parametrization triplet singlet oxygen concentrations, alongside their reactivities.

Language: Английский

Efficient Production of Reactive Oxidants by Atmospheric Bacterial-Derived Organic Matter in the Aqueous Phase

Environmental Science & Technology, Journal Year: 2025, Volume and Issue: unknown

Published: March 27, 2025

Hydroxyl radicals (•OH), singlet oxygen (1O2*), and organic triplet excited states (3C*) play key roles as oxidants ("reactive intermediates (RIs)") in forming oxidizing aqueous aerosols. Bioaerosols are ubiquitous the atmosphere, but little is known about their photochemical behavior contributions to atmospheric photochemistry. We investigated of aqueous-phase cellular matter (COM) extracellular polymeric substances (EPS) from cultured bacteria isolated PM2.5, focusing on production 3C*, 1O2*, •OH. The molecular size aromaticity chromophores fluorophores COM EPS increased with weight (MW). Apparent quantum yields (ΦRI) up 10% 5% were measured for 1O2* respectively, which upper range previously reported values. This indicated that contain photosensitizers highly efficient at producing 3C*. ΦRI concentrations ([RI]ss) decreased MW due higher-MW molecules engaging charge-transfer interactions disrupt processes oxidant production. Machine learning models used understand predict based measurable optical chemical properties EPS. study provides new insights into bioaerosols can

Language: Английский

Don’t Forget About the Microbes on Surfaces in Indoor Atmospheric Chemistry

ACS ES&T Air, Journal Year: 2024, Volume and Issue: 1(8), P. 743 - 746

Published: July 10, 2024

Language: Английский