A Reference signed on January 12, 1949 required a comprehensive air pollution investigation in the Detroit River area. To answer the questions in the Reference, the following objectives were established to (1) determine the sources, nature and amounts of atmospheric contaminants resulting from combustion of fuels, (2) determine the sources, nature and amounts of atmospheric contaminants resulting from industrial processes, (3) determine the effects of meteorological factors on the dissemination and diffusion of atmospheric contaminants, (4) determine the effect of the atmospheric contaminants upon (a) health, (b) vegetation, (c) safety, and (d) economy, and (5) determine controls necessary (vessels only). (a) Cost, and (b) by whom should the cost be borne. The report presents the environmental and meteorological findings obtained in 1952 and correlation of these data with those obtained in 1951.