accretion

in atmospheric chemistry
https://doi.org/10.1351/goldbook.A00058
The process by which aerosols grow in size by external addition of various chemical species; a form of agglomeration.
Source:
PAC, 1990, 62, 2167. 'Glossary of atmospheric chemistry terms (Recommendations 1990)' on page 2169 (https://doi.org/10.1351/pac199062112167)