methods to estimate emissions and the associated emission factors for air pollutants, which have been published in the EMEP/CORINAIR Emission Inventory Guidebook on Emission Inventories and Projections TFEIP. Intensity targets Coal, being mostly carbon, emits a lot of when burnt: it has a high emission intensity. Natural gas, being methane (), has 4 hydrogen atoms to burn for each one of carbon and thus has medium emission intensity. Sources of emission factors Greenhouse gases 2006 IPCC Guidelines for National Greenhouse Gas Inventories Revised 1996 IPCC Guidelines for National Greenhouse Gas Inventories (reference manual). IPCC Emission Factor Database National Inventory Report: Greenhouse Gas Sources and Sinks in Canada. United Kingdom's emission factor database. Air pollutants AP 42, Compilation of Air Pollutant Emission Factors US Environmental Protection Agency EMEP/CORIMAIR 2007 Emission Inventory Guidebook. Fugitive emissions leaks from ethylene and other chemical plants. Well-to-refinery carbon intensity (CI) of all major active oil fields globally In an August 31, 2018 article by Masnadi et al. which was published by Science, the authors used "open-source oil-sector CI modeling tools" to "model well-to-refinery carbon intensity (CI) of all major active oil fields globally—and to identify major drivers of these emissions." They compared 90 countries with the highest crude oil footprint. The Science study, which was conducted by Stanford University found that Canadian crude oil is the "fourth-most greenhouse gas (GHG) intensive in the world" behind Algeria, Venezuela and Cameroon. See also Air pollution AP 42 Compilation of Air Pollutant Emission Factors Carbon footprint Emission inventory Energy intensity Greenhouse gas and Greenhouse effect IPCC list of greenhouse gases Kaya identity Low-carbon economy Low-carbon fuel standard Mobile emission reduction credit Radiative forcing Resource intensity Vehicle emission standard References External links Washington Post article with an example of change in carbon intensity A Note On Variations in UK Grid Electricity CO2 Intensity with Time IPCC Special Report on Emissions Scenarios Statistical Energy Review 2012 World Energy Council:Odyssee Database International Energy Agency: CO2 emissions from fuel combustion Electricity carbon intensity in European Member States: Impacts on GHG emissions of electric vehicles A hybrid LCA-WTW method to assess the carbon footprint of electric vehicles Carbon emissions intensity from different regions Air pollution emissions Atmospheric dispersion modeling Industrial emissions control Environmental engineering Energy economics