Estimating Emissions from Sources

EPA. 1984. Locating and estimating air emissions from sources of acrylonitrile. Research Triangle Park, NC U.S. Environmental Protection Agency, Office of Air Quality Planning and Standards. EPA-450/4-84-007a. 

California Air Resources Board (CARB), Methodology for Estimating Emissions from On-Road Motor Vehicles, Vol. I Introduction and Overview, L. Hrynchuk and B. Effa, Planning and Technical Support Division Mobile Source Emission Inventory Branch, 1996. (For information about documents or MVEI7G Model, contact Public Information Office or Transportation Activity Section, California Air Resources Board. We thank Mr. E. E. Yotter and Dr. John Holmes, Chief, Research Division, for providing this information (1999).)... 

U.S. Environmental Protection Agency, Locating and Estimating Air Emissions from Sources of Dioxins and Furans (May 1997). http //www.epa.gov/ttnchiel/le/dioxin.pdf... 

The estimated emissions from these two sources in ethane cracking are set out in Table 7.6 ... 

Emissions of phosgene most commonly arise as a result of its release during manufacture and use, its formation from the decomposition of chlorinated hydrocarbons, and its formation from the photochemical oxidation of air-borne chlorinated organic materials, particularly the C, and C chloroalkanes, and chloroethenes. The location and estimation of air emissions from sources of phosgene have been described by the US Environmental Protection Agency [2088b], Catastrophic emissions and accidental spills and leaks are discussed in Section 3.6. 

Locating and Estimating Air Emissions from Sources of Formaldehyde (Revised), U.S. EPA, Office of Air and Radiation, Office of Air Quality Planning and Standards, 1991. 

The estimates in Table 3 represent one inventory however, a further estimate of uncertainties may be found by comparing other recent ongoing inventories for the UK. Pain et alJ have very recently estimated UK emissions from livestock production systems (including tillage crops) at 240 Gg NHj yr while ApSimon et al. (personal communication) estimate a figure of around 280 Gg NHj yr h Including the non-agriciiltiiral sources at around 40 Gg NHj yr the official estimate recently adopted by the Department of the Environment is 320 Gg NHj yr h If these estimates are contrasted with the other recent estimate of UK... 

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. 

Forests can act as sources of some of the trace gases in the atmosphere, such as hydrocarbons, hydrogen sulfide, NO, and NH3. Forests have been identified as emitters of terpene hydrocarbons. In 1960, Went (10) estimated that hydrocarbon releases to the atmosphere were on the order of 108 tons per year. Later work by Rasmussen (11) suggested that the release of terpenes from forest systems is 2 x 10 tons of reactive materials per year on a global basis. This is several times the anthropogenic input. Yet, it is important to remember that forest emissions are much more widely dispersed and less concentrated than anthropogenic emissions. Table 8-2 shows terpene emissions from different types of forest systems in the United States. 

In estimating concentrations from area sources, it is important to know whether there is one source surrounded by areas of no emissions or whether the source is just one element in an area of conhnuous but varying emissions. 

For sources having a large component of emissions from low-level sources, the simple Gifford-Hanna model given previously as Eq. (20-19), X = Cqju, works well, especially for long-term concentrations, such as annual ones. Using the derived coefficients of 225 for particulate matter and 50 for SO2, an analysis of residuals (measured minus estimated) of the dependent data sets (those used to determine the values of the coefficient C) of 29 cities for particulate matter and 20 cities for SOj and an independent data set of 15 cities for particulate matter is summarized in Table 20-1. For the dependent data sets, overestimates result. The standard deviations of the residuals and the mean absolute errors are about equal for particulates and sulfur dioxide. For the independent data set the mean residual shows... 

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. 

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