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The AP 42 Compilation of Air Pollutant Emission Factors is a compilation of the US Environmental Protection Agency (EPA)'s emission factor information on air pollution, first published in 1968. As of 2018 [update] , the last edition is the 5th from 2010.
The AP 42 Compilation of Air Pollutant Emission Factors is a compilation of emission factors of air pollutants, in other words numbers which relate the quantity of a pollutant released into the ambient air with a certain activity. This compilation was first compiled and published by the US Public Health Service in 1968. In 1972, it was revised and issued as the second edition by the US Environmental Protection Agency EPA. In 1985, the subsequent fourth edition was split into two volumes: Volume I has since included stationary point and area source emission factors, and Volume II includes mobile source emission factors. Volume I is currently in its fifth edition and is available on the Internet. [1] Volume II is no longer maintained as such, but roadway air dispersion models for estimating emissions from on-road vehicles and from non-road vehicles and mobile equipment are available on the Internet. [2]
In routine common usage, Volume I of the emission factor compilation is very often referred to as simply AP 42.
Air pollution emission factors are usually expressed as the weight of the pollutant divided by a unit weight, volume, distance, or duration of the activity emitting the pollutant (e.g., kilograms of particulate matter emitted per megagram of coal burned). The factors help to estimate emissions from various sources of air pollution. In most cases, the factors are simply averages of all available data of acceptable quality, and are generally assumed to be representative of long-term averages.
The equation for the estimation of emissions before emission reduction controls are applied is:
and for emissions after reduction controls are applied:
| where: | |
| E | = emissions, in units of pollutant per unit of time |
|---|---|
| A | = activity rate, in units of weight, volume, distance, or duration per unit of time |
| EF | = emission factor, in units of pollutant per unit of weight, volume, distance, or duration |
| ER | = overall emission reduction efficiency, in % |
Emission factors are used by atmospheric dispersion modelers and others to determine the amount of air pollutants being emitted from sources within industrial facilities. [3] [ page needed ]
| Chapter 1 | External Combustion Sources |
|---|---|
| Chapter 2 | Solid Waste Disposal |
| Chapter 3 | Stationary Internal Combustion Sources |
| Chapter 4 | Evaporation Loss Sources |
| Chapter 5 | Petroleum Industry |
| Chapter 6 | Organic Chemical Process Industry |
| Chapter 7 | Liquid Storage Tanks |
| Chapter 8 | Inorganic Chemical Industry |
| Chapter 9 | Food and Agricultural Industries |
| Chapter 10 | Wood Products Industry |
| Chapter 11 | Mineral Products Industry |
| Chapter 12 | Metallurgical Industry |
| Chapter 13 | Miscellaneous Sources |
| Chapter 14 | Greenhouse Gas Biogenic Sources |
| Chapter 15 | Ordnance Detonation |
| Appendix A | Miscellaneous Data & Conversion Factors |
| Appendix B.1 | Particle Size Distribution Data and Sized Emission Factors for Selected Sources |
| Appendix B.2 | Generalized Particle Size Distributions |
| Appendix C.1 | Procedures for Sampling Surface/Bulk Dust Loading |
| Appendix C.2 | Procedures for Laboratory Analysis of Surface/Bulk Dust Loading Samples |
Chapter 5, Section 5.1 "Petroleum Refining" discusses the air pollutant emissions from the equipment in the various refinery processing units as well as from the auxiliary steam-generating boilers, furnaces and engines, and Table 5.1.1 includes the pertinent emission factors. Table 5.1.2 includes the emission factors for the fugitive air pollutant emissions from the large wet cooling towers in refineries and from the oil/water separators used in treating refinery wastewater.
The fugitive air pollutant emission factors from relief valves, piping valves, open-ended piping lines or drains, piping flanges, sample connections, and seals on pump and compressor shafts are discussed and included in the report EPA-458/R-95-017, "Protocol for Equipment Leak Emission Estimates" which is included in the Chapter 5 section of AP 42. That report includes the emission factors developed by the EPA for petroleum refineries and for the synthetic organic chemical industry (SOCMI).
In most cases, the emission factors in Chapter 5 are included for both uncontrolled conditions before emission reduction controls are implemented and controlled conditions after specified emission reduction methods are implemented.
Chapter 7 "Liquid Storage Tanks" is devoted to the methodology for calculating the emissions losses from the six basic tank designs used for organic liquid storage: fixed roof (vertical and horizontal), external floating roof, domed external (or covered) floating roof, internal floating roof, variable vapor space, and pressure (low and high). The methodology in Chapter 7 was developed by the American Petroleum Institute in collaboration with the EPA.
The EPA has developed a software program named "TANKS" which performs the Chapter 7 methodology for calculating emission losses from storage tanks. The program's installer file along with a user manual, and the source code are available on the Internet. [4]
Chapters 5 and 7 discussed above are illustrative of the type of information contained in the other chapters of AP 42. Many of the fugitive emission factors in Chapter 5 and the emissions calculation methodology in Chapter 7 and the TANKS program also apply to many other industrial categories besides the petroleum industry.
Exhaust gas or flue gas is emitted as a result of the combustion of fuels such as natural gas, gasoline (petrol), diesel fuel, fuel oil, biodiesel blends, or coal. According to the type of engine, it is discharged into the atmosphere through an exhaust pipe, flue gas stack, or propelling nozzle. It often disperses downwind in a pattern called an exhaust plume.
The National Emission Standards for Hazardous Air Pollutants (NESHAP) are air pollution standards issued by the United States Environmental Protection Agency (EPA). The standards, authorized by the Clean Air Act, are for pollutants not covered by the National Ambient Air Quality Standards (NAAQS) that may cause an increase in fatalities or in serious, irreversible, or incapacitating illness.
An emission intensity is the emission rate of a given pollutant relative to the intensity of a specific activity, or an industrial production process; for example grams of carbon dioxide released per megajoule of energy produced, or the ratio of greenhouse gas emissions produced to gross domestic product (GDP). Emission intensities are used to derive estimates of air pollutant or greenhouse gas emissions based on the amount of fuel combusted, the number of animals in animal husbandry, on industrial production levels, distances traveled or similar activity data. Emission intensities may also be used to compare the environmental impact of different fuels or activities. In some case the related terms emission factor and carbon intensity are used interchangeably. The jargon used can be different, for different fields/industrial sectors; normally the term "carbon" excludes other pollutants, such as particulate emissions. One commonly used figure is carbon intensity per kilowatt-hour (CIPK), which is used to compare emissions from different sources of electrical power.
A State Implementation Plan (SIP) is a United States state plan for complying with the federal Clean Air Act, administered by the Environmental Protection Agency (EPA). The SIP, developed by a state agency and approved by EPA, consists of narrative, rules, technical documentation, and agreements that an individual state will use to control and clean up polluted areas.
New Source Performance Standards (NSPS) are pollution control standards issued by the United States Environmental Protection Agency (EPA). The term is used in the Clean Air Act Extension of 1970 (CAA) to refer to air pollution emission standards, and in the Clean Water Act (CWA) referring to standards for water pollution discharges of industrial wastewater to surface waters.
A major stationary source is a source that emits more than a certain amount of a pollutant as defined by the U.S. Environmental Protection Agency (EPA). The amount of pollutants allowed for certain new sources is defined by the EPA's New Source Performance Standards (NSPRS).
A gas flare, alternatively known as a flare stack, flare boom, ground flare, or flare pit, is a gas combustion device used in places such as petroleum refineries, chemical plants and natural gas processing plants, oil or gas extraction sites having oil wells, gas wells, offshore oil and gas rigs and landfills.
Atmospheric dispersion modeling is the mathematical simulation of how air pollutants disperse in the ambient atmosphere. It is performed with computer programs that include algorithms to solve the mathematical equations that govern the pollutant dispersion. The dispersion models are used to estimate the downwind ambient concentration of air pollutants or toxins emitted from sources such as industrial plants, vehicular traffic or accidental chemical releases. They can also be used to predict future concentrations under specific scenarios. Therefore, they are the dominant type of model used in air quality policy making. They are most useful for pollutants that are dispersed over large distances and that may react in the atmosphere. For pollutants that have a very high spatio-temporal variability and for epidemiological studies statistical land-use regression models are also used.
The Air Quality Modeling Group (AQMG) is in the U.S. EPA's Office of Air and Radiation (OAR) and provides leadership and direction on the full range of air quality models, air pollution dispersion models and other mathematical simulation techniques used in assessing pollution control strategies and the impacts of air pollution sources.
This page is out of date and should be considered an historic reference only
A volume source of pollution is a three-dimensional source of pollutant emissions. Essentially, it is an area source with a third dimension.
An emission 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.
The following outline is provided as an overview of and topical guide to air pollution dispersion: In environmental science, air pollution dispersion is the distribution of air pollution into the atmosphere. Air pollution is the introduction of particulates, biological molecules, or other harmful materials into Earth's atmosphere, causing disease, death to humans, damage to other living organisms such as food crops, and the natural or built environment. Air pollution may come from anthropogenic or natural sources. Dispersion refers to what happens to the pollution during and after its introduction; understanding this may help in identifying and controlling it.
SAFE AIR is an advanced atmospheric pollution dispersion model for calculating concentrations of atmospheric pollutants emitted both continuously or intermittently from point, line, volume and area sources. It adopts an integrated Gaussian puff modeling system. SAFE AIR consists of three main parts: the meteorological pre-processor WINDS to calculate wind fields, the meteorological pre-processor ABLE to calculate atmospheric parameters and a lagrangian multisource model named P6 to calculate pollutant dispersion. SAFE AIR is included in the online Model Documentation System (MDS) of the European Environment Agency (EEA) and of the Italian Agency for the Protection of the Environment (APAT).
The Clean Air Act (CAA) is the United States' primary federal air quality law, intended to reduce and control air pollution nationwide. Initially enacted in 1963 and amended many times since, it is one of the United States' first and most influential modern environmental laws.
To protect the environment from the adverse effects of pollution, many nations worldwide have enacted legislation to regulate various types of pollution as well as to mitigate the adverse effects of pollution. At the local level, regulation usually is supervised by environmental agencies or the broader public health system. Different jurisdictions often have different levels regulation and policy choices about pollution. Historically, polluters will lobby governments in less economically developed areas or countries to maintain lax regulation in order to protect industrialisation at the cost of human and environmental health.
True vapor pressure (TVP) is a common measure of the volatility of petroleum distillate fuels. It is defined as the equilibrium partial pressure exerted by a volatile organic liquid as a function of temperature as determined by the test method ASTM D 2879.
An external floating roof tank is a storage tank commonly used to store large quantities of petroleum products such as crude oil or condensate. It consists of an open- topped cylindrical steel shell equipped with a roof that floats on the surface of the stored liquid. The roof rises and falls with the liquid level in the tank. As opposed to a fixed roof tank there is no vapor space (ullage) in the floating roof tank. In principle, this eliminates tank breathing loss and greatly reduces the evaporative loss of the stored liquid. There is a rim seal system between the tank shell and roof to reduce rim evaporation.
Air quality laws govern the emission of air pollutants into the atmosphere. A specialized subset of air quality laws regulate the quality of air inside buildings. Air quality laws are often designed specifically to protect human health by limiting or eliminating airborne pollutant concentrations. Other initiatives are designed to address broader ecological problems, such as limitations on chemicals that affect the ozone layer, and emissions trading programs to address acid rain or climate change. Regulatory efforts include identifying and categorising air pollutants, setting limits on acceptable emissions levels, and dictating necessary or appropriate mitigation technologies.
Mobile source air pollution includes any air pollution emitted by motor vehicles, airplanes, locomotives, and other engines and equipment that can be moved from one location to another. Many of these pollutants contribute to environmental degradation and have negative effects on human health. To prevent unnecessary damage to human health and the environment, environmental regulatory agencies such as the U.S. Environmental Protection Agency have established policies to minimize air pollution from mobile sources. Similar agencies exist at the state level. Due to the large number of mobile sources of air pollution, and their ability to move from one location to another, mobile sources are regulated differently from stationary sources, such as power plants. Instead of monitoring individual emitters, such as an individual vehicle, mobile sources are often regulated more broadly through design and fuel standards. Examples of this include corporate average fuel economy standards and laws that ban leaded gasoline in the United States. The increase in the number of motor vehicles driven in the U.S. has made efforts to limit mobile source pollution challenging. As a result, there have been a number of different regulatory instruments implemented to reach the desired emissions goals.