In this study, cloud formation and its seeding efficiency at room temperature have been envestigated by different particles such as ambient aerosols, salt, and smoke induced by burning match. In the first step, the effect of ambient aerosol concentration on the time of clearing cloud was considered. Since the aerosols concentration is almost constant during the day, therefor it is accepted as base point for comparison of not-seeded and seeded condition for cloud formation and precipitation. The effect of aerosols concentration variation in different days also were considered. In the second step, the effect of salt and smoke injected as seeding nuclei to the chamber on the cloud clearing time was studied. The salt solution density were used with 20, 30 and 40 gllit.
The time of cloud clearing by the salt nuclei is less than ambient aerosols. The results showed, the more salt solution density, the less cloud clearing time. In most experiments with
increasing smoke concentration the precipitation increased too and extraordinary amounts of smoke concentration rarely caused cloud to be overseed. The experimental results on nucleation efficiency showed that hygroscopic and giant salt particles are more efficient than smaller smoke particles but with respect to higher concentrations of smoke it is observed that the cloud has precipitated in shorter time by smoke nuclei. In fact, if it would be possible to make the experiments under the quantity control coditions, the cloud could be cleaned with salt nuclei in the shorter time.