Some results of field measurements of incident UV radiation intensity, total and aerosol optical depth of the atmosphere, ozone 0concentration, sulfur gas and aerosol content in the surface atmospheric layer during the moist season of 1995 (from June to October) are presented. We studied the aerosol washout by tropical rains and its reconstruction after the rains. The multielement analysis of aerosol samples and rain precipitation has been carried out. The intensification of volcanic matter emission that occurred late in August and early in September has also been analyzed.