Emissions factors

Compilation of yiirPollution Emission Factors, Pub. No. AP-42, 5th ed., U.S. Environmental Protection Agency, Research Triangle Park, N.C., 1989. Compilation of A.ir Pollution Emission Factors, Vol 2. Mobile Sources, Pub. No. AP-42, 5th ed., U.S. Environmental Protection Agency, Research Triangle Park, N.C., 1989. 

Compilation ofi Air Pollution Emission Factors, Vol. 1, Stationay Point and Area Sources, AP-42, 4th ed., Suppl. E, U.S. Environmental Protection Agency, Washiagton, D.C., 1993. 

Aluminum-jacketed calcium silicate insulation with an emissivity factor of 0.05. To convert inches to miUimeters, multiply by 25.4, to convert dollars per 1 miUion British thermal units to dollars per 1 nulhon kilojoules, multiply by 0.948, = 5/9 ( F — 32). 

The insertion of low-emissivity floating shields within the evacuated space can effectively reduce the heat transport by radiation. The effect of the shields is to greatly reduce the emissivity factor. For example, for N shields or N + 2) surfaces, an emissivity of the outer and inner surface of and an emissivity of the shields of the emissivity factor reduces to... 

In addition, the PMio NAAQS will continue to place emphasis on quantifying and reducing particulate emissions in the less than 10- Im particle-size range. Particle size-specific emission factors have been developed for many sources, and size-specific emission standards have been developed in a number of states. These standards are addressing concerns related to HAP emissions of hea y metals, which are generaUy associated with the submicron particles. 

Table 2 Ammonia emission factors from cattle in the UK...

Term N available for emission and uncertainty (kgN animal yr ) Best loss esimate and uncertainty (% of available N) Eguivalent component NEl emission factor (kg N animal yr )... 

Values inferred from component emission factors and given as indicators only. Uncertainty estimates assume that maximum emissions are associated with large N availability. 

Source Population (thousands) Average emission factor (kgN individual yr-lor % where noted) Contribution to UK emission (Gg NH yr- ) Percent contrihntic (%)... 

Based on Aman, 1992, ° and uncertainty in poultry emission factor. 

If we assume the emissivity factor to be 0.85 the shortfall in the heat dissipation is nearly made up. However, it would be a matter of laboratory testing to establish the suitability of the enclosure section chosen. Otherwise the thickness of the enclosure may be slightly increased and the calculations repeated. 

To develop an emission inventory for an area, one must (1) list the types of sources for the area, such as cupolas, automobiles, and home fireplaces (2) determine the type of air pollutant emission from each of the listed sources, such as particulates and SO2 (3) examine the literature (9) to find valid emission factors for each of the pollutants of concern (e.g., "particulate emissions for open burning of tree limbs and brush are 10 kg per ton of residue consumed") (4) through an actual count, or by means of some estimating technique, determine the number and size of specific sources in the area (the number of steelmaking furnaces can be counted, but the number of home fireplaces will probably have to be estimated) and (5) multiply the appropriate numbers from (3) and (4) to obtain the total emissions and then sum the similar emissions to obtain the total for the area. 

Valid emission factors for each source of pollution are the key to the emission inventory. It is not uncommon to find emission factors differing by 50%, depending on the researcher, variables at the time of emission measurement, etc. Since it is possible to reduce the estimating errors in the... 

Actual emission data are available from many handbooks, government publications, and literature searches of appropriate research papers and journals. It is always wise to verify the data, if possible, as to the validity of the source and the reasonableness of the final number. Some emission factors, which have been in use for years, were only rough estimates proposed by someone years ago to establish the order of magnitude of the particular source. 

Emission factors must be also critically examined to determine the tests from which they were obtained. For example, carbon monoxide from an automobile will vary with the load, engine speed, displacement, ambient temperature, coolant temperature, ignition timing, carburetor adjustment, engine condition, etc. However, in order to evaluate the overall emission of carbon monoxide to an area, we must settle on an average value that we can multiply by the number of cars, or kilometers driven per year, to determine the total carbon monoxide released to the area. 

Compilation of Air Pollutant Emission Factors, AP-42 and Supplements, U.S, Environmental Protection Agency, Research Triangle Park, NC, 1973-1992. 

Section 130, Emission Factors requires revising emission inventory factors every 3 years ... 

Within 6 months after enactment of the Qean Air Act Amendments of 1990, and at least every 3 years thereafter, the Administrator shall review and, if necessary, revise, the methods ( emission factors ) used for purposes of this Act to estimate the quantity of emissions of carbon monoxide, volatile organic compounds, and oxides of nitrogen from sources of such air pollutants (including area sources and mobile sources). In addition, the Administrator shall permit any person to demonstrate improved emissions estimating techniques, and following approval of such techniques, the Administrator shall authorise the use of such techniques. Any such technique may be approved only after appropriate public participation. Until the Administrator has completed the revision required by this section, nothing in this section shall be construed to affect the validity of emission factors established by the Administrator before the date of the enactment of the Clean Air Act Amendments of 1990. 

Air Pollution Emission Factors for Agricultural Field Burning... 

The processing of cotton, from the field to the cloth, releases both inorganic and organic particulate matter to the atmosphere. Also, adhering pesticide residues may be emitted at the cotton gin exhaust. Table 30-19 lists the emission factors for particulate matter from cotton ginning operations. 

Particulate Matter Emission Factors for Asphaltic Concrete Plants... 

Air PollutiDn Emission Factors for Fiber Glass Manufacturing without Controls... 

Table 12.9 Average emission factors for plant items...

In addition to chemicals covered under TRI, many other chemicals are released. For example, the EPA Office of Air Quality Planning and Standards has compiled air pollutant emission factors for determining the total air emissions of priority pollutants (e.g., VOCs, SO, NO, CO, particulates, etc.) from many refinery sources. The EPA Office of Aerometric Information Retrieval System (AIRS) contains a wide range of information related to stationary sources of air pollution, including the emissions of a number of air pollutants which may be of concern within a particular industry. With the exception of volatile organic compounds (VOCs), there is little overlap with the TRI chemicals reported above. 

Estimate some typical emission factors and make a comparison between industry sectors. One way to express an emission factor is in terms of the tons of pollution produced per year per unit capita of production. Develop a table for several common pollutants (e.g., SO, NO, HCs, others) for each industry sector you select. What conclusions can you draw from these comparisons. 

Chapter 7 of EPA s Compilation Of Air Pollutant Emission Factors (AP-42). Click the filename to download the file. 

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