Pollution directly attributed to humans in the air can cause serious problems. Problems that result from air pollution are numerous including damage to plants, animals, and people. Many of the pollutants are gases but others can be particulate matter that can obscure vision, cause lung illness, grime on buildings, and erode metals Particulates are a variety of sizes of particles. The primary sources are fuel, combustion, and industrial discharge.

Sulfur oxides are created from the burning of sulfur-bearing fuels, especially coal and low-grade petroleum products. The most abundant of the gases include sulfur dioxide, which is a colorless gas that is very corrosive to many metals. Sulfur oxides cause leaf and tree injury and irritate upper respiratory tracts in humans. They also corrode metals, disintegrate book pages and leather, destroy plants, and erode statues.