9:30 AM - 9:45 AM
[AAS12-15] Observational study of wet removal process of black carbon particles
Keywords:Black carbon, wet deposition
In this study, we observed relationships between size-dependent removal efficiency (RE) and size-dependent CCN activity in Tokyo during summer 2014 and 2015. The size-dependent RE was determined by measuring both size-resolved BC number concentrations in air and in rainwater. The size-dependent CCN activity was estimated by measuring coating thickness and hygroscopicity of BC particles.
Out of 32 rain events during observation period, the strong size-dependent RE was successfully explained by the size-dependent CCN activity for 29 rain events, indicating that nucleation scavenging was the dominant removal process of BC particles. For the other rain events, impaction scavenging might be also effective for larger BC particles.