2026-02-09 カリフォルニア大学リバーサイド校（UCR）
＜関連情報＞
- https://news.ucr.edu/articles/2026/02/09/trace-gases-play-unseen-role-cloud-droplet-formation
- https://www.science.org/doi/10.1126/sciadv.adx0960
微量ガスの除去は雲粒の形成を増加させることも減少させることも可能である Removal of trace gases can both increase and decrease cloud droplet formation
Elavarasi Ravichandran, Sanghee Han, Abigail S. Williams, Veronica Berta, […] , and Markus D. Petters
Science Advances Published:14 Jan 2026
DOI:https://doi.org/10.1126/sciadv.adx0960
Abstract
Aerosols consist of liquid or solid particles dispersed in a gas. Aerosol measurements generally rely on drying the particles before quantifying their physicochemical properties. This drying can potentially remove semivolatile compounds from the particles. Here, we show size-resolved cloud condensation nuclei (CCN) measurements quantifying the hygroscopicity parameter in the presence and absence of a denuder. The denuder efficiently removed alkanes and weakly functionalized acids, aldehydes, and alcohols with fewer than 10 carbon atoms from the gas phase. Denuding organic compounds perturbed the CCN-derived hygroscopicity parameter by up to 50%. Denuding either rendered the particles more or less CCN active, and the direction of the effect depended on sample relative humidity and trace gas concentration. The effect was weakest in early spring and strongest in late spring and summer. The measurements demonstrate an unexpectedly strong coupling between the particle and gas phase, influencing CCN activity through either volatilization or surface adsorption, or both.
