ITEP Web Training - Tribal Emission Inventory Software Solution (TEISS)

There are several ways you can estimate how much air pollution is being released by a source. For tribes, unless you have a large industrial source of pollution or one of the source types covered by the EPA models, it is usually most practical to use emission factors to estimate emissions for reservation sources.

Measure it directly- Continuous emissions monitoring systems (CEMS) or source testing.
This is usually expensive and only done for sources, such as large power plants, that release large amounts of pollution. CEMS can be installed in smokestacks to measure the amount of gaseous pollutants being emitted. Source testing emission rates are derived from short-term emission measurements taken at a stack or vent. Emission data can then be extrapolated to estimate long-term emissions from the same or similar sources.

Use Emission Factors- Factors and methods are contained in TEISS.
This is how TEISS estimates emissions. An emission factor is a ratio that relates the emissions of a pollutant to an activity level that can be easily measured, such as amount of fuel burned or material produced.

Emissions factors are used in a basic estimating equation:
    E= EF * A
    E = emissions rate
    EF = emissions factor
    A = Activity data

For every ton of wood burned in a conventional woodstove, AP-42 tells us that 30.6 pounds of PM10 are released to the atmosphere. Through surveys you find that people living on your reservation burn approximately 2,000 tons of wood a year in their conventional woodstoves (woodstoves with no emission controls on them). To estimate emissions of PM10 from wood burning in conventional woodstoves, you would do the following calculation:
30.6 pounds PM10/ton wood burned x 2,000 tons wood burned/year = 61,200 lbs PM10 released to the air from conventional woodstoves each year.

TEISS includes EFs for many different source types within its emission calculators. These EFs come from a guidance document maintained by EPA called AP-42 Compilation of Air Pollutant Emission Factors, Volume 1: Stationary Point and Area Sources. You can access the AP-42 document online at www.epa.gov/ttn/chief/ap42/index.html . The TEISS emission calculators contain links to AP-42.
When using TEISS you, the emission inventory preparer, must determine A, the activity data, needed to make the estimate. The TEISS calculators will tell you what kind of data is needed for A for the sources you are interested in calculating. You will need to collect the data for A to enter into TEISS. TEISS will then do the math for you to give you the emission rate (E) based on the activity data (A) that you entered into the calculator.

Use Emission Estimation Models - Some are contained in TEISS.
EPA has several models available that can be used to estimate emissions from certain types of sources. These models attempt to take into account the many factors that can effect emissions from these sources to make an estimate of emissions. A model is a computer program that prompts the user to enter site-specific information, then uses that information to do complex calculations to come up with emission estimates. We will list here the models that are included on the TEISS installation CD. TEISS can easily import the results from these models.

TANKS - Estimates VOC and hazardous air pollutant (HAP) emissions from fixed and floating-roof organic liquid (such as fuels) storage tanks. This program is used for larger tanks used for bulk storage of fuels and other organic liquids. You can estimate emissions from smaller tanks, such as those found at gas stations, using EFs contained in the TEISS calculators.

LANDGEM - Estimates emissions of methane, carbon dioxide and HAPS from landfills.

WATER9 - Estimates compound-specific air emissions from wastewater collection treatment systems

MOBILE6 - Calculates EFs for many pollutants from on-road vehicles (cars, trucks, motorcycles). The EFs produced by this model must be combined with user-supplied data on vehicle miles traveled to get emissions estimates.

NONROAD - Estimates emissions from non-road vehicles on a county basis. Tribes who have collected activity data on non-road vehicles for their reservations have to take extra steps to estimate emissions using the results from this model. The method of doing this is described in detail in a later part of this web-course.

Material Balance - Calculations are done outside of TEISS, resulting emissions can be entered into TEISS.
This method is most commonly used for activities where volatile organic compounds (VOCs), such as cleaning solvents, are being used in large quantities. It works best when there are high losses of VOCs to the atmosphere through evaporation and no material is lost due to chemical reactions. The basic equation is:
Material in - material out = pollutant released into the air.

50 gallons of parts-cleaning fluid are delivered to an auto repair shop by a solvent vendor. When the solvent vendor returns 2 months later to collect the solvent for recycling, the find only 48 gallons remain. It is assumed that those 2 gallons evaporated as the parts-cleaner was being used. If each gallon of parts cleaner contains 0.5 pounds of VOCs you can calculate that (2 gallons x 0.5 pounds/gallon = 1 pound VOCs) 1 pound of VOCs were lost to the air over those two months. To get an annual emission rate you would do the following calculation: 1 pound VOCs released/2 months x 12 months/year = 6 pounds VOCs released per year.