Pollutans deposition in Santiago City associated to rain and dew events.

We have measured the chemical composition (anions and cations) of rain and dew waters collected in Santiago City during the years 1995 to 1999. From t hese data it was calculated the total amount of contaminants removed by the se processes. It is concluded that their relative relevance depends on the total anual rain. Dew deposition is more relevant in dry years, while rain is the predominant removal mechanism in rainy years. The material incorpora te to these hydrometeors reflects the composition of the particulate matter in the city atmosphere. The concentrations measured in dew waters are inve rsely proportional to the volumen of water collected. This indicates that d eposition and dew formation are unrelated events. However, a small increase in atmospheric instability resulting from the condensation of water cannot be completely disregarded. The corrosion of material (copper and steel) exposed to dews and rains was also measured at the same localization. It is concluded that the atmosphere is highly corrosive. There is a strong selectivity in the incorporation of elements to the exposed metalic matrix.