Figure 91. Sulfation versus sulfur dioxide (Dec 1964 Feb 1965) 17 cm2/ 2 means was 0.013 ppm, as compared to 0.042 ppm sulfur dioxide per 1.0 mg S03/100 cm day found in Nashville. These data indicate that compounds other than sulfur dioxide have a greater influence on the sulfation rates in St. Louis than in Nashville. SULFUR DIOXIDE (West-Gaeke) Three separate networks of sulfur dioxide samplers were operated during this Study. One network consisting of three sites was equipped with 2-hour sequential samplers. It was operated from May 1963 to July 1964. Results from it are not reported. A second network of twenty 24-hour samplers was operated from December 1963 to February 1964, and another network consisting of forty 24-hour samplers plus ten 2-hour sequential samplers was operated from December 1964 to February 1965. Results of the 20-site network operated in the winter of 1963-64 are given in Table 33 and the results of the 40-site network are listed in Tables 34 and 35. The ranges of results were 0.00-0.24 ppm for the network of twenty 24-hour samplers (December 1963 February 1964), 0.00-0.26 ppm for the network of forty 24-hour samplers (December 1964 - February 1965), and 0.00-0.86 ppm for the network of ten 2-hour sequential samplers (December 1964 February 1965). The locations of 19 of the 24-hour sampler stations were the same for the winters of 1963-64 and 1964-65. Comparison of the results from these stations (Table 36) shows that the sulfur dioxide concentrations were significantly higher for the winter of 1964-65 than for the winter of 1963-64. The possible reasons for this are: (1) sulfur dioxide concentrations for St. Louis are beginning an upward trend; (2) the meteorological conditions were more conducive to high air pollution during the 1964-65 season than during 1963-64; (3) the 1963-64 samples faded as a |