Where does air pollution come from?
Air pollution is the presence of hazardous pollutants in the air that are linked to health issues and detriment to the planet. Pollutants can include harmful biological molecules as well as particulates. Air pollution is linked to a range of respiratory diseases and, according to a report by the World Health Organization, it is believed to be the cause of over 7 million deaths globally in 2012.
Sources of Air Pollution
Air pollution emanates from a wide range of sources which can be grouped into mobile sources, stationary sources, area sources, and natural sources.
- Mobile sources of air pollution include vehicles used in all modes of transport from ships to trucks to airplanes. Mobile source of air pollution is one of the worst forms of air pollution due to the composition of toxins released into the atmosphere (which includes lead). In recent years, the number of vehicles on the world’s roads has seen a steady increase. Therefore, the emissions in the atmosphere have also increased. Mobile sources of air pollution pose a challenge to the regulation of emissions where the government enforces ban in harmful toxins such as the US ban on the use of leaded gasoline.
- Stationary sources of air pollution are the immobile anthropogenic sources of air pollution and consist of power plants, heavy industries, boilers, and oil refineries. The stationary sources are defined as the sources emitting at least 10 tons of emissions of an individual pollutant per year. These establishments produce massive amounts of pollutants and authorities have placed several policies to counter the pollutants, for instance, the state of New Jersey requires all facilities considered as stationary sources of air pollution to report the composition of their emissions to the state.
- Area sources of air pollution are small sources which individually produce minimal amounts of emissions, but collectively they account for significant portions of total emissions. The area sources of air pollution account for over 50% of all particulate matter emissions globally. Examples of area sources of air pollution include urban centers and agricultural areas.
- Natural sources of air pollution are naturally occurring events which cause air pollution and include volcanic eruptions, biological decay, dust storms, and wildfires. Natural sources of air pollutions are often overlooked when discussing air pollution. However, these sources eclipse the artificial sources of pollutants emitted globally. For instance, 90 million tons of the pollutant nitrogen oxides are estimated to be released from natural sources compared to 24 million tons produced from human-made sources. Volcanoes are estimated to emit over 200 million tons of sulfur oxide into the atmosphere compared to 69 million tons released from artificial sources.
Effects of Air Pollution
Some pollutants in the air such as sulfur dioxide react with the atmosphere to produce acidic compounds which fall back to the earth as acid rain. The acid rain contaminates the water and the soils thereby affecting the biosphere. Infiltration of the acid rain in the soil changes the pH levels of the soil and hence affects agricultural activities carried out using the soil.