Photochemical Air Pollutants and Their Effects on Men and Animals

The physical and chemical characteristics of photochemical smog and the photochemical oxidants have been described. Aerometric data on the total oxidant concentrations found in the large urban communities affiliated with the Public Health Service, Continuous Air Monitoring Program (CAMP) network have been documented for 1964 and 1965. Similarly, the number of days on which the total oxidant concentrations equalled or exceeded 0.05, 0.1, and 0.15 ppm, respectively, have been delineated for each of the affiliated cities in this network. The 0.05 ppm and 0.1 ppm levels are routinely found and are exceeded in all of the cities affiliated with this network for highly significant percentages of days of the year, while the 0.15 ppm level is exceeded only in Los Angeles thus far for a significant percentage of the total number of days of the year. However, much higher maximum hourly and maximum five-minute levels are attained in all of the cities (but one) during the year. Specific biologically adverse effects of photochemical oxidants on man and animals at each of these levels as well as at other concentrations will be presented in another study. 88 references, 4 tables.