Air pollution occurs when harmful substances, including particles and biological molecules are introduced into Earth's atmosphere. May cause disease, allergy or death of humans; can also cause damage to other living organisms, such as animals and food crops, and can damage the natural or built environment. Human activity and natural processes can generate air pollution.
Indoor air pollution and poor urban air quality are listed as two of the world's worst toxic pollution problems in the 2008 Blacksmith Institute World Worst Polluted Places report. According to the World Health Organization report of 2014 , air pollution in 2012 caused the death of about 7 million people worldwide, a more or less echo estimate of one of the International Energy Agency.
Emission factors of air pollutants report representative values that attempt to relate the amount of a released pollutant to ambient air with an activity associated with the release of that pollutant. These factors are generally expressed as the weight of the pollutant divided by the unit weight, volume, distance or duration of the activity emitted by the pollutant (eg, Kilograms of particles emitted per ton of charcoal burned). These factors facilitate the estimation of emissions from various sources of air pollution. In most cases, these factors are simply averages of all available data of acceptable quality, and are generally assumed to be representative of long-term averages.
There are 12 compounds on the list of persistent organic pollutants. Dioxins and furans are two of them and are intentionally created by the combustion of organic compounds, such as burning open plastics. These compounds are also endocrine disruptors and can mutate human genes.
The US Environmental Protection Agency has published a compilation of air pollutant emission factors for a wide range of industrial sources. The United Kingdom, Australia, Canada and many other countries have published similar compilations, as well as the European Environment Agency.