This report presents the results for precipitation runoff studies from boldly exposed zinc surfaces at three sites having substantially different environments: Washington DC, Newport OR, and Albany OR. The relationship between atmospheric corrosion and precipitation runoff chemistries were examined for experiments of up to 33 months duration by the use of geochemical modeling with a software package available from the U.S. Geological Survey. Total precipitation runoff rates for the
three sites were determined, as well as contributions from strong acids, weak acids and dry deposition to the total rate. Cumulative zinc runoff losses were linear with respect to both time and precipitation volume, which produce effective models for long-term corrosion mass loss based on runoff loss rates. Precipitation runoff rates for Washington DC, Newport OR, and Albany OR were found to be 0.90, 0.69, and 0.49 :m Zn/y respectively. Contributions to the total precipitation runoff rate from dry deposition (0.26 :m Zn/y), strong acids (0.24 :m Zn/y), and weak acids (0.40 :m Zn/y) reactions were found for the Washington DC site. These values correspond to dry deposition calculations from particle and molecular transport data in the atmosphere. Precipitation runoff rates for Newport OR and Albany OR were found to be due solely to weak acid reactions. Keywords: zinc, atmospheric corrosion, precipitation runoff, corrosion film, geochemical modeling, wet deposition, dry deposition, deposition velocity.