Quantity of a substance or substances released from a given area or mass of a material at a set point in time; i.e., milligrams per square meter per hour.
An estimate or statistical average of the rate at which a contaminant is released to the atmosphere as a result of some activity, such as combustion or industrial production, divided by the level of that activity. The Emission Factor (EF), therefore, relates the average quantity of each contaminant emitted according to an appropriate base quantity. EFs are usually expressed as a weight of contaminant divided by a unit weight, volume, distance or duration of associated activity that emits the pollutant (e.g., kg of SO2 emitted per tonne of coal burned). EFs are usually obtained from data of varying degrees of accuracy and may be presented for either uncontrolled sources or facilities having air pollution control devices in place.
the relationship between the amount of pollution produced and the amount of raw material processed or burned. For example, the emission factor for oxides of nitrogen from fuel oil combustion in an industrial boiler would be the number of pounds of oxides of nitrogen emitted per 1000 gallons of fuel oil burned. By using the emission factor of a pollutant and specific data regarding quantities of material used by a given source, it is possible to compute emissions for the source. This approach is used in preparing an emissions inventory
an average value that relates the quantity of a pollutant released to the atmosphere with the amount of activity associated with the process releasing that pollutant
a relationship between the amount of emissions that are released and the activity of the producer
For stationary sources, the relationship between the amount of pollution produced and the amount of raw material processed or burned. For mobile sources, the relationship between the amount of pollution produced and the number of vehicle miles travelled. Emissions for a given source can be calculated from the emission factor of a pollutant and specific data regarding quantities of materials used by the source. This approach is used in preparing an emissions inventory.
The mass of particulate matter produced per unit mass of fuel consumed (pounds per ton, grams per kilogram).
A measure of the average amount of a specified pollutant or material emitted for a specific type of fuel or process.
A number, similar to a conversion factor, that converts or translates an input, output, or action into an emission reduction.
A factor relating activity data (such as tonnes of fuel consumed, tonnes of product produced) and absolute GHG emissions.
The relationship between the amount of pollution produced and the amount of raw material processed. For example, an emission factor for a blast furnace making iron would be the number of pounds of particulates per ton of raw materials.
For air pollution produced during an industrial process, the ratio of output ( air pollutants or other by-product such as waste heat) to some measure of productivity, such as input quantity of fuel or raw materials or amount of final product. As written by the U.S. Environmental Protection Agency, an emission factor is a representative value that attempts to relate the quantity of a pollutant released to the atmosphere with an activity associated with the release of that pollutant. These factors are usually expressed as the weight of pollutant divided by a unit weight, volume, distance, or duration of the activity emitting the pollutant (e.g., kilograms of particulate emitted per megagram of coal burned).
The amount of pollution (pounds per ton) released to the atmosphere per unit weight of dry fuel consumed during combustion.
The statistical average of the amount of a specific pollutant emitted from each type of polluting source in relation to the unit quantity of material handled; processed or burned. For example, the emission factor of oxides in nitrogen in fuel oil combustion is 119 lbs., over 1,000 gallons of fuel oil used. By using the emission factor of a pollutant and specific data regarding quantities of material used by a given source, it is possible to compute emissions for that source—information necessary for an emission inventory.
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.