An exposure test of porcelain-enameled steel and aluminum specimens is being conducted. The present report gives the results of the third-year inspection. Changes in gloss and color were taken as criteria of weathering. Comparison of the gloss and color changes with data obtained by the National Air sampling Network indicated that air pollution by acidic contaminants was a factor in site severity. A direct relation existed between acid resistance and weather resistance. This relation was apparent, however, only when averages were considered. There were individual exceptions within groups of enamels of the same general type. In addition, enamels of different types, such as aluminum and steel enamels, having the same acid resistance (citric acid spot test) did not necessarily show the same weather resistance. Further, some red and yellow enamels with good acid resistance showed poor color stability. It was found, however, that this poor stability could be predicted by specially developed cupric sulfate test. As a group, the regular glossy enamels for steel showed the best weather resistance among the carious types tested.