Page 78 - Fundamentals of Air Pollution

TABLE 4-4

Distribution of Cities by Population Class and Particulate Matter Concentration, 1957-1967
Average particulate matter concentration, /nm/m 3
Less More
Population than than
class 40 40-59 60-79 80-99 100-119 120-139 140-159 160-179 180-199 200 Total

Over 3 million 1 1 2
1 — 3 million — — — — — — 2 1 — — 3
0.7-1 million — — 1 — 2 — 4 — — — 7
400-700,000 — — — 4 5 6 1 1 1 — 18
100-400,000 — 3 7 30 24 17 12 3 2 1 99
50-100,000 2 20 28 16 12 6 5 1 3 93
25-50,000 — 5 24 12 12 10 2 1 2 3 71
10-25,000 — 7 18 19 9 5 2 3 1 — 64
Under 10,000 1 5 7 15 11 2 1 2 — — 44
Total 1 22 77 108 79 52 31 16 8 7 401
Source: U.S. Environmental Protection Agency, "Air Quality Data from 1967" (Rev. 1971), Office of Air Programs, Pub, APTD 0471, Research Triangle
Park, NC, 1971.