The study was conducted to investigate the effects of deposition on galvanized steel and painted panels using mobile covering/deionized spray devices at exposure sites located at Steubenville, OH and Research Triangle Park (RTP), NC. Ambient rain and deionized spray runoff samples from the panels were collected on an event basis for seven months and underwent detailed chemical analysis. The analysis indicated that the dry deposition of acid gases at the sites increased the dissolution rate of galvanized steel corrosion products. Although the average SO2 level in Steubenville was ten times the RTP value, the rate of Zn dissolution was only 1.9. This result in conjunction with the presence of large amounts of Ca in the Steubenville runoff samples suggest that neutralization of acidic gases by dry deposited basic particulates may be important at the Steubenville site. At the RTP site low levels of anions were found in the runoff from the painted panel with H(1+) as the most abundant cation. This result is consistent with the lack of reactivity towards acidic gases due to the absence of alkaline paint components. (Copyright (c) 1989 Marcel Dekker, Inc.)