Major U.S. Air Pollution Episodes       of Historic Significance
¥U.S. air quality degraded shortly after the beginning of the industrial revolution
¥Coal burning in Central and Midwest U.S.
1939 St. Louis Smog Nov 28
1948 Donora, PA in the Monongahela River Valley
20 deaths, 1000Õs took ill in 5 days Oct 27
¥Prompted Air Pollution Control Act of 1955
Ignored automobiles