Environmental effects include: acid precipitation damaging trees, soils, and bodies of water; eutrophication caused by the deposit of nutrients found in air pollutants, which enter water and cause growth of algae, fish kills, and destruction of plant and animal diversity; ozone depletion resulting in damaged crops such as soybeans and the reduction of crop yields; and potentially global warming.
Acid precipitation is produced, sometimes long distances from the source, when sulfur is released into the air as a pollutant, combines with oxygen to form sulfur dioxide and then in the presence of ozone or hydrogen peroxide becomes sulfur trioxide which dissolves in water and produces sulfuric acid. It also occurs when the nitrogen from the atmosphere is heated to temperatures found in steam boilers and internal combustion engines, combines with oxygen to form nitrogen oxide and nitrogen dioxide, and then dissolves in water to form nitric and nitrous acids.
Visibility, of great significance to people who are visiting national and state parks and wilderness areas, is affected by haze caused by air pollution from hundreds of miles away. Haze is created by light being absorbed or scattered by particles in the air, which then reduces clarity and may change the color of the surrounding air. The particles may also increase respiratory illness and decrease lung function, indicating that haze may not just be an aesthetic concern.
Air quality issues may also be associated with fracking activities used to find and utilize energy sources embedded in rock formations beneath the surface of the ground. There have been emissions into the air of methane, VOCs, hazardous air pollutants, and greenhouse gases. Diesel fuel used in fracking borings also contributes to air pollution.