Emissions inventories

An emission inventory is a list of the amount of pollutants from all sources entering the air in a given time period. The boundaries of the area are fixed (8). 

The method used to develop the emission inventory does have some elements of error, but the other two alternatives are expensive and subject to their own errors. The first alternative would be to monitor continually every major source in the area. The second method would be to monitor continually the pollutants in the ambient air at many points and apply appropriate diffusion equations to calculate the emissions. In practice, the most informative system would be a combination of all three, knowledgeably applied. 

Qean Air Act Amendments of 1990 (10) strengthened the emission inventory requirements for plans and permits in nonattainment areas. The amendments state  

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. 

A typical example will illustrate the procedure. Suppose we wish to determine the amount of carbon monoxide from oil furnaces emitted per day, during the heating season, in a small city of 50,000 population  

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Procedures for Emission Inventory Preparation, Vol. 1 -4, Pub. No. EPA 450-4-81-026A-E, U.S. Environmental Protection Agency, Research Triangle Park,N.C, 1981. 

V. R. Phillips, Ammonia Emission Inventory for Agriculture in the UK. Final Report, CSA2141/OC9117, Institute of Grassland and Environmental Research, North Wyke, Okehampton, UK, 1995. 

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... 

To compile the emission inventory requires a determination of the number and types of units of interest in the study area. It would be of interest, for example, to know the number of automobiles in the area and the number of kilometers each was driven per year. This figure would require considerable time and expense to obtain. Instead, it can be closely approximated by determining the liters of gasoline sold in the area during the year. Since a tax is collected on all gasoline sold for highway use, these figures can be obtained from the tax collection office. 

A major change in the emissions for an area will occur if control equipment is installed. This can be shown in the emission inventory to illustrate the effect on the community. 

By keeping the emission inventory current and updating it at least yearly as fuel uses change, industrial and population changes occur, and control equipment is added, a realistic record for the area is obtained. 

The tools available for site selection include climatological data, topography, population data, emission inventory data, and diffusion modeling. Climatological data are useful in relating meteorology to emission patterns. For example, elevated levels of photochemical oxidant are generally related... 

Pollutant concentration maps may be constructed as shown in Fig. 15-5 (14). In this example, elevated levels of ambient particulate matter are associated with population centers. For a given geographic area, isopleths, lines showing equal concentrations of a pollutant, are drawn on a map. Regions of high concentration are quickly identified. Further action may be taken to determine the cause, such as review of emission inventories of additional sampling. 

The emission inventory and the initial and boundary conditions of pollutant concentrations have a large impact on the ozone concentrations calculated by photochemical models. 

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

To implement the research provisions, the EPA plans to conduct research in emissions inventories, atmospheric modeling, source/ambient monitoring, control technologies, health, and ecological monitoring. Both ecological... 

Why are "oxides of nitrogen" and "oxides of sulfur" usually reported in emission inventory tables rather than the actual oxidation states ... 

The reasons for performing a source test differ. The test might be necessary for one or more of the following reasons (1) To obtain data concerning the emissions for an emission inventory or to identify a predominant source in the area. An example of this would be determination of the hydrocarbon release from a new type of organic solvent used in a degreasing tank. 

Using the Gaussian plume model and the other relations presented, it is possible to compute ground level concentrations C, at any receptor point (Xq, in the region resulting from each of the isolated sources in the emission inventory. Since Equation (2) is linear for zero or linear decay terms, superposition of solutions applies. The concentration distribution is available by computing the values of C, at various receptors and summing over all sources. 

Re-opener a permit condition that requires the permitting authority, at a specified time after permit issuance, to review and revise, if necessary, the permit based on new information such as the findings from post-construction monitoring, updated emissions inventories, updated modeling, research, or information on air pollution effects to terrestrial, aquatic, and visibility resources. 

An integrated package that creates air pollution permits, calculates and reports on emission inventory information and individual air pollution incidents. 

The first task in selecting an abatement method is the preparation of an emission inventory. The inventory is the basis of planning and the selection of options. By the preparation of an inventory, all emission sources requiring treatment can be determined and recorded. The emission inventory... 

Toxic Chemicals Release Reporting-Emissions Inventory (Section 313)... 

USEPA publishes toxic chemicals release (i.e., emissions inventory) form [Section 302(c)]... 

The federal test procedure for new vehicle certification IS limited to a maximum acceleration rate of 3.3 mph/sccond and a maximum speed of 57 mph (and even that speed is for a veiy short duration). Based upon extensive data collected in Baltimore, Spokane, and Atlanta, more than 8.5 percent of all speeds exceeded 57 mph, and more than 88 percent of trips contained acceleration activity exceeding 4 mph/sec-ond. In fact, more than one-third of the trips monitored included an acceleration rate at some point during the trip of more than 7 mpli/second. Similarly, more than 15 percent of the deceleration activity exceeded -3.5 mph/second. Hence, enrichment events are significant in real-world emissions inventories. 

Estimates of urban NOx emissions and trends are generally limited to those provided by the developed countries which have the detailed emission Inventories. As In the case of other pollutants, the USA contributes the most on a per-country basis to the global NOx emissions per year. Because of the Inaccuracy of the data base used. It Is difficult to discern trends In these emissions. However, with new control technologies being Implemented for both stationary and mobile sources, downward trends In the developed countries may be more prevalent In the future years. Unfortunately, the opposite trend Is likely to occur In the developing countries. 

Kato, N. and Akimoto, H. (1992). Anthropogenic emissions of SO2 and NO in Asia Emission inventories, Atmos. Environ. 26A, 2997-3017. 

Pacyna EG, Pacyna JM, Steenhuisen F, Wilson D. 2006. Global anthropogenic mercury emission inventory for 2000. Atmospheric Environment 40 4048 063. 

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