Gerrebos Nealan G A, Zaks Julia, Gregson Florence K A, Walton-Raaby Max, Meeres Harrison, Zigg Ieva, Zandberg Wesley F, Bertram Allan K
Department of Chemistry, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada.
Department of Chemistry, Thompson Rivers University, Kamloops, British Columbia V2C 0C8, Canada.
Environ Sci Technol. 2024 Dec 10;58(49):21716-21728. doi: 10.1021/acs.est.4c09148. Epub 2024 Nov 28.
Biomass burning organic aerosol (BBOA) is a major contributor to organic aerosol in the atmosphere. The impacts of BBOA on climate and health depend strongly upon their physicochemical properties, including viscosity and phase behavior (number and types of phases); these properties are not yet fully characterized. We collected BBOA field samples during the 2021 British Columbia wildfire season to constrain the viscosity and phase behavior at a range of relative humidities and compared them to previous studies on BBOA. Particles from all samples exhibited two-phased behavior with a polar hydrophilic phase and a nonpolar hydrophobic phase. We used the poke-flow viscosity technique to estimate the viscosity of the particles. Both phases of the BBOA had viscosities of >10 Pa s at relative humidities up to 50%. Such high viscosities correspond to mixing times within 200 nm BBOA particles of >5 h. Two phases and high viscosity have implications for how BBOA should be treated in atmospheric models.
生物质燃烧有机气溶胶（BBOA）是大气中有机气溶胶的主要贡献者。BBOA对气候和健康的影响在很大程度上取决于其物理化学性质，包括粘度和相行为（相的数量和类型）；这些性质尚未得到充分表征。我们在2021年不列颠哥伦比亚省野火季节收集了BBOA现场样本，以确定一系列相对湿度下的粘度和相行为，并将其与之前关于BBOA的研究进行比较。所有样本的颗粒均表现出两相行为，即极性亲水相和非极性疏水相。我们使用戳流粘度技术来估计颗粒的粘度。在相对湿度高达50%时，BBOA的两个相的粘度均>10 Pa·s。如此高的粘度对应于200 nm BBOA颗粒内>5小时的混合时间。两相和高粘度对大气模型中BBOA的处理方式具有影响。
