LOW-COST AUTOMATED RAIN COLLECTOR AND ITS APPLICATION TO THE STUDY OF WET ONLY DEPOSITION IN SAO-PAULO (BRAZIL)

An automatic rain collector was developed with emphasis on simplicity, construction with readily available low-cost materials, inexpensive maintenance and reliable operation at temperatures above freezing point. The rain sensor is of the heated AC conductometric type and the circuit includes electronic protections against false triggering by electrical transients. With this collector, the first studies of chemical characterization of wet only deposition were made in Sao Paulo over the period of November 1988 to June 1990. Results are presented and compared with previous total deposition studies. For this period the volume-weighted mean values of the pH and conductivity were 4.6 and 19 mu S cm(-1), respectively.