Variations in different sized water insoluble particulate matter in rain water

Temporal variations in different sized water insoluble particles in rain water during five rainfall events were investigated in a suburban area. The mass of particles ranged: 45–88 % (particle size > 8 μm), 12–43 % (1–8 μm) and 0–13 % (0.4–1 μm). A high concentration and following sharp decrease of the particles larger than 8 μm were observed at the initial stage of rainfall; the rate of the decrease was higher in the heavier rain. In many cases, the mass concentration of particles in rain water showed an inverse correlation with rainfall intensity. The variation of the smaller size particles was less significant compared to the larger ones.