Question: What atmospheric phenomenon prompted the 1948 smog episode in Donora, Pennsylvania?

Answer: temperature inversion

Question: What was the significance of the smog episodes in Donora, Pennsylvania, and London?

Answer: Legislation was passed to regulate air pollution.

Question: How did the levels of sulfur dioxide during the Great Smog of London compare to acceptable levels today?

Answer: The levels were about 20 times higher.

Question: According to recent estimates, how many people died as a result of the Great Smog of London?

Answer: 12,000

Question: Which pollutant was involved in the Donora smog of 1948?

Answer: fluorine