Correct Option: C

The most common sources of air pollution include particulates, ozone, nitrogen dioxide, and sulfur dioxide. The largest sources of SO2 emissions are from fossil fuel combustion at power plants (73%) and other industrial facilities (20%). Smaller sources of SO2 emissions include industrial processes such as extracting metal from ore, and the burning of high sulfur containing fuels by locomotives, large ships, and non-road equipment. It is linked with a number of adverse effects on the respiratory system.