Mary Ochsenhirt Amdur studied the effects of smog on what town? 
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.
i don't know