Hydrogen Sulfide Darkening of Exterior Paint

Abstract

Hydrogen sulfide reacts with heavy metal salts in exterior paints to form a precipitate which discolors the paint. Variables of this reaction include: type and concentration of heavy metal in the paint, age and condition of the paint surface, concentration and time of hydrogen sulfide exposure as well as the temperature and relative humidity of the ambient atmosphere. Variables of this reaction will be reviewed in terms of literature references and field results in the San Francisco Bay Area.