资源环境科技发展态势分析平台

Raindrops impacting water or soil generate bubbles, which can burst and eject spray aerosols. However, aerosols resulting from raindrop impact are often overlooked in atmospheric aerosol studies, and their production flux and chemical characteristics have not been quantified. Here we measured the production rate, size distribution, and chemical composition of spray aerosols from laboratory simulations of raindrops impinging on seawater and soils. It was found that the number of spray aerosols produced from each raindrop impact on seawater grows exponentially with increasing raindrop diameter. The spray aerosol production flux was then calculated for a range of rain rates. The spray aerosol production rate from raindrop impact on soil was approximately one order of magnitude lower than that from impact on seawater, but the production rate was enhanced drastically when water ponded on the soil surface. The chemical compositions of the generated spray aerosols were characterized by a single particle mass spectrometer. Generally, spray aerosol from raindrop impact on seawater contained sodium, potassium, calcium, and other metals as well as some organic carbon. The spray aerosols from raindrop impact on soils contained metals and some organic carbon. These aerosol production flux and composition findings are critical to identification of raindrop impact produced aerosols and further investigation of their roles in the atmosphere.