Emission inventory

An emission inventory (or emissions inventory) is an accounting of the amount of pollutants discharged into the atmosphere. An emission inventory usually contains the total emissions for one or more specific greenhouse gases or air pollutants, originating from all source categories in a certain geographical area and within a specified time span, usually a specific year.

An emission inventory is generally characterized by the following aspects:

Why: The types of activities that cause emissions

What: The chemical or physical identity of the pollutants included, and the quantity thereof

Where: The geographic area covered

When: The time period over which emissions are estimated

How: The methodology to use

Emission inventories are compiled for both scientific applications and for use in policy processes.

Use

Emissions and releases to the environment are the starting point of every environmental pollution problem. Information on emissions therefore is an absolute requirement in understanding environmental problems and in monitoring progress towards solving these. Emission inventories provide this type of information.

Emission inventories are developed for a variety of purposes:

Policy use: by policy makers to

track progress towards emission reduction targets

develop strategies and policies or

Scientific use: Inventories of natural and anthropogenic emissions are used by scientists as inputs to air quality models

Policy use

Two more or less independent types of emission reporting schemes have been developed:

Annual reporting of national total emissions of greenhouse gases and air pollutants in response to obligations under international conventions and protocols; this type of emissions reporting aims at monitoring the progress towards agreed national emission reduction targets;

Regular emission reporting by individual industrial facilities in response to legal obligations; this type of emission reporting is developed to support public participation in decision-making.

Examples of the first are the annual emission inventories as reported to the United Nations Framework Convention on Climate Change (UNFCCC) for greenhouse gases and to the UNECE Convention on Long-Range Transboundary Air Pollution (LRTAP) for air pollutants. In the United States, a national emissions inventory is published annually by the United States Environmental Protection Agency. This inventory is called the "National Emissions Inventory", and can be found here: [2]

Examples of the second are the so-called Pollutant Release and Transfer Registers.