 An air pollution emission source An emission factor can be defined as the average emission rate of a given pollutant for a given source, relative to units of activity. Emission factors can be used to derive estimates of gas emissions (for instance, greenhouse gas emissions) based on the amount of fuel combusted or on industrial production levels. The level of precision of the resulting estimates depends significantly on the activity in question. Carbon dioxide (CO2) emissions from the combustion of fuel can be estimated with a high degree of certainty regardless of how the fuel is used as these emissions depend almost exclusively on the carbon content of the fuel, which is generally known with a high degree of certainty. In contrast, the levels of non-CO2 emissions from combustion depend on the precise nature of the activity in which the fuel is being combusted. For instance, methane (CH4) emissions from transport depend on a vehicle's type, whether the vehicle has been fitted with emissions controls and so on. Therefore, because of the uncertainties involved, the estimates of non-CO2 emissions from transport using emission factors are much less precise than estimates of CO2 emissions. Image File history File links AirPollutionSource. ...
Image File history File links AirPollutionSource. ...
Many of the compounds which are dangerous to the environment can also be harmful to humans in the long-term range and come from mineral and fossil sources or are produced by humans themselves. ...
Top: Increasing atmospheric CO2 levels as measured in the atmosphere and ice cores. ...
A combustion reaction taking place in a igniting match Combustion or burning is a complex sequence of exothermic chemical reactions between a fuel and an oxidant accompanied by the production of heat or both heat and light in the form of either a glow or flames. ...
Carbon dioxide is a chemical compound composed of one carbon and two oxygen atoms. ...
General Name, Symbol, Number carbon, C, 6 Chemical series nonmetals Group, Period, Block 14, 2, p Appearance black (graphite) colorless (diamond) Standard atomic weight 12. ...
Methane is a chemical compound with the molecular formula CH4. ...
Emission Factors and National Greenhouse Gas Inventory Reporting One of the most important uses of emission factors is for the reporting of national greenhouse gas inventories under the United Nations Framework Convention on Climate Change. The Intergovernmental Panel on Climate Change (IPCC) publishes default emission factors covering a range of different activities and fuels for use in national inventories. The primary source for IPCC default emission factors is the 'Revised 1996 IPCC Guidelines for National Greenhouse Gas Inventories'. Greenhouse gas inventories are a type of emission inventory that are developed for a variety of reasons. ...
UNFCCC logo. ...
IPCC is the science authority for the UNFCCC The Intergovernmental Panel on Climate Change (IPCC) was established in 1988 by two United Nations organizations, the World Meteorological Organization (WMO) and the United Nations Environment Programme (UNEP), to evaluate the risk of climate change brought on by humans, based mainly on...
Particularly for non-CO2 emissions, there is often a very high degree of uncertainty surrounding these emission factors when they are applied to individual countries. In general, the use of country-specific emission factors provides more accurate estimates of emissons than the use of the default emission factors. According to the IPCC, if an activity is a major source of emissions for a country, it is 'good practice' to develop a country-specific emission factor for that activity.
Sources of emission factors The mission of the United States Environmental Protection Agency (EPA) is to protect human health and to safeguard the natural environment: air, water, and land. ...
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