The topic is approached from the viewpoint of community air-pollution programs and control. After a brief discussion of the economic costs of atmospheric pollution in an industrial area, a skeleton outline of the important factors in weathering by pollutants is presented. A few of the factors are considered in detail under the general headings of soiling, erosion, and corrosion.Significant differences in weathering are found for industrial, rural, marine, and very dry climates. Most community surveys include routine tests of the dirtiness of the air but exclude corrosion tests, although this factor is of great economic importance.Methods of corrosion testing are considered, and it is concluded that they are not feasible yet for community surveys. Increasing interest in corrosion, however, is undoubtedly leading to a broader understanding of the problem.