Liggio John, Makar Paul, Li Shao-Meng, Hayden Katherine, Darlington Andrea, Moussa Samar, Wren Sumi, Staebler Ralf, Wentzell Jeremy, Wheeler Michael, Leithead Amy, Mittermeier Richard, Narayan Julie, Wolde Mengistu, Blanchard Dane, Aherne Julian, Kirk Jane, Lee Colin, Stroud Craig, Zhang Junhua, Akingunola Ayodeji, Katal Ali, Cheung Philip, Ghahreman Roya, Majdzadeh Mahtab, He Megan, Ditto Jenna, Gentner Drew R
Air Quality Research Division, Environment and Climate Change Canada, 4905 Dufferin Street, Toronto, Ontario M3H 5T4, Canada.
College of Environmental Sciences and Engineering, Peking University, Beijing, China.
Sci Adv. 2025 Jan 3;11(1):eadr0259. doi: 10.1126/sciadv.adr0259.
Dry deposition is an important yet poorly constrained process that removes reactive organic carbon from the atmosphere, making it unavailable for airborne chemical reactions and transferring it to other environmental systems. Using an aircraft-based measurement method, we provide large-scale estimates of total gas-phase organic carbon deposition rates and fluxes. Observed deposition rates downwind of large-scale unconventional oil operations reached up to 100 tC hour, with fluxes exceeding 0.1 gC m hour. The observed deposition lifetimes (τ) were short enough (i.e., 4 ± 2 hours) to compete with chemical oxidation processes and affect the fate of atmospheric reactive carbon. Yet, much of this deposited organic carbon cannot be accounted for using traditional gas-phase deposition algorithms used in regional air quality models, signifying underrepresented, but influential, chemical-physical surface properties and processes. Furthermore, these fluxes represent a major unaccounted contribution of reactive carbon to downwind freshwater ecosystems that outweigh terrestrial sources, necessitating the inclusion of dry deposition in aquatic carbon balances and models.
干沉降是一个重要但约束不足的过程，它从大气中去除活性有机碳，使其无法参与大气化学反应，并将其转移到其他环境系统中。我们使用基于飞机的测量方法，对气相有机碳的总沉积速率和通量进行了大规模估算。在大规模非常规石油作业的下风方向观测到的沉积速率高达100 tC/小时，通量超过0.1 gC/(m²·小时)。观测到的沉积寿命（τ）足够短（即4±2小时），能够与化学氧化过程竞争，并影响大气活性碳的归宿。然而，使用区域空气质量模型中传统的气相沉积算法无法解释大部分这种沉积的有机碳，这表明化学物理表面性质和过程的代表性不足但具有影响力。此外，这些通量代表了活性碳对下风方向淡水生态系统的一个主要未计算贡献，超过了陆地来源，因此有必要将干沉降纳入水生碳平衡和模型中。
