Ajith T C, Windwer Eli, Li Chunlin, Fang Zheng, Kompalli Sobhan Kumar, Nursanto Farhan R, Olayemi Temitope E, Ese Julius I, Sharpe Steven A L, Fraund Matthew, Moffet Ryan C, Laskin Alexander, Fry Juliane L, Rudich Yinon
Department of Earth and Planetary Sciences Weizmann Institute of Science Rehovot Israel.
College of Environmental Science and Engineering Tongji University Shanghai China.
J Geophys Res Atmos. 2024 Dec 16;129(23):e2024JD041802. doi: 10.1029/2024JD041802. Epub 2024 Nov 30.
This study investigates the new particle formation (NPF) events at an urban location in the Eastern Mediterranean. Particle size distribution, particulate chemical composition, and gaseous pollutants were monitored in Rehovot, Israel (31°53″N 34°48″E) during two campaigns: from April 29 to 3 May 2021 (Campaign 1) and from May 3 to 11 May 2023 (Campaign 2), coinciding with an intensive bonfire burning festival. The organic aerosols (OA) source apportionment identified two major factors-Hydrocarbon-like OA and Biomass-burning OA-as well as two secondary factors-MO-OOA (more oxidized-oxygenated OA) and LO-OOA (low oxidized oxygenated OA). NPF events were frequently observed during the day (mostly well-defined nucleation events) and at night (burst of ultrafine mode particles without any discernible growth). A condensation sink value of (9.4 ± 4.0) × 10 s during Campaign 1 and (14.2 ± 6.0) × 10 s during Campaign 2 was obtained. The daytime events were associated with enhanced sulfuric acid proxy concentrations of (2-12) × 10 molecules cm, suggesting the role of gas-phase photochemistry in promoting NPF. A novel approach of hybrid positive matrix factorization analysis was used to deconvolve the chemical species responsible for the observed events. The results suggest the involvement of multiple components, including ammonium sulfate and MO-OOA, in the nucleation; Nitrate, HOA and LO-OOA participate in the subsequent particle growth for the daytime events. Nighttime events involve only semi-volatile species (LO-OOA, HOA and nitrate) along with ammonium sulfate.
本研究调查了地中海东部一个城市地区的新粒子形成（NPF）事件。在以色列雷霍沃特（北纬31°53″，东经34°48″）进行了两次监测活动，期间对粒径分布、颗粒物化学成分和气态污染物进行了监测：一次是在2021年4月29日至5月3日（活动1），另一次是在2023年5月3日至11日（活动2），这两次活动都恰逢一个密集的篝火燃烧节。有机气溶胶（OA）源解析确定了两个主要因素——类烃OA和生物质燃烧OA，以及两个次要因素——MO - OOA（氧化程度更高的含氧OA）和LO - OOA（氧化程度较低的含氧OA）。白天（大多为明确的成核事件）和夜间（超细模态粒子爆发且无明显增长）均频繁观测到NPF事件。活动1期间获得的凝结汇值为(9.4 ± 4.0)×10⁻³ s⁻¹，活动2期间为(14.2 ± 6.0)×10⁻³ s⁻¹。白天的事件与硫酸替代物浓度增强（(2 - 12)×10⁹分子/cm³）相关，这表明气相光化学在促进NPF中发挥了作用。采用了一种混合正矩阵因子分解分析的新方法来解析导致观测事件的化学物种。结果表明，包括硫酸铵和MO - OOA在内的多种成分参与了成核过程；硝酸盐、HOA和LO - OOA参与了白天事件中随后的粒子生长。夜间事件仅涉及半挥发性物种（LO - OOA、HOA和硝酸盐）以及硫酸铵。
