Air pollutants, sulfur dioxide and sodium chloride form water-soluble sulfates and chlorides in the rust. These soluble salts are responsible for the early failure of paint coatings. The effect that various levels of these corrosion-stimulating contaminants at the steel/paint interface have on paint durability was studied by both natural and artificial weathering. Even levels of 100 mg/m² of sodium chloride and 1000 mg/m² of sulfates were sufficient to shorten the life of most paint types; however zinc rich silicate-type coatings were unaffected by the presence of contaminants. -- AATA