Mary Ochsenhirt Amdur studied the effects of which historic air inversion that killed 20 people?
Mary Amdur: Mary Ochsenhirt Amdur (February 18, 1921 – February 16, 1998) was an American toxicologist and public health researcher who worked primarily on pollution. Mary Amdur:  She was charged with studying the effects of the 1948 Donora smog, so she specifically looked into the effects of inhaling Sulfuric acid by experimenting on guinea pigs. 1948 Donora smog: The 1948 Donora smog was a historic air inversion that resulted in a wall of smog that killed 20 people and sickened 7,000 more in Donora, Pennsylvania, a mill town on the Monongahela River, 24 mi southeast of Pittsburgh.
1948 Donora smog