Enhanced sulfate formation in mixed biomass burning and sea-salt interactions mediated by photosensitization: effects of chloride, nitrogen-containing compounds, and atmospheric aging

Atmospheric chemistry and physics, Journal Year: 2025, Volume and Issue: 25(1), P. 425 - 439

Published: Jan. 13, 2025

Abstract. Discrepancies persist between modeled simulations and measured sulfate concentrations in the marine boundary layer, especially when air is influenced by biomass burning plumes. However, there has been a notable dearth of research conducted on interactions sea-salt aerosol plumes, impeding comprehensive understanding formation. This work studied formation mixing real (BB) extracts NaCl, mimicking internal mixtures BB particles. BB–NaCl particles had significantly higher rate than incense (IS)–NaCl For fresh particles, followed trend corn straw (CS)–NaCl > rice (RS)–NaCl wheat (WS)–NaCl IS–NaCl. The filter sample aging was achieved exposure to OH• generated from UV irradiation. After aging, RS–NaCl exhibited highest enhancement rates among all due RS NaCl. Bulk aqueous experiments spiked with NaCl using model photosensitizers (PSs) nitrogen-containing organic compounds (NOCs), pyrazine (CHN), 4-nitrocatechol (CHON) revealed positive effects chloride PS–CHON system negative PS–CHN Our suggests that reaching or near coastal areas can affect via photosensitizer-mediated reactions, potentially exacerbating pollution.

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