Emission Inventories and EI Data Sets

Sarah Kelly, ITEP

Les Benedict, St. Regis Mohawk Tribe

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Emission Inventories and EI Data Sets

What is an emissions inventory? How are EI data used in modeling?

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What is an EI? (cont.)

Account of air pollution emissions For a specific geographic area

Reservation County State Country

For a specific time period Annual Seasonal Any other time period

For specific pollutants Criteria pollutants Air toxics

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How are EIs used in modeling? Starting point for modeling Provides other data needed for model

Activity data Time period of air pollutant emissions

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What is an EI? (cont.)

Point sources Inventoried

individually

Area sources Inventoried

collectively

Mobile sources Separately

inventoried area source

Biogenic sources Separately

inventoried area source

What air pollution sources are included in an EI?

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Types of Sources Included in EIs

Point Sources Large, stationary, identifiable

sources of emissions Typically manufacturing or

production plants Includes confined "stack" &

individual unconfined "fugitive" sources

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Types of Sources Included in EIs Area Sources

Smaller sources, not qualifying as point sources under given emission cutoffs

Collection of similar, small sources

Source spread over large area

Emissions estimated as group

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Types of Sources Included in EIs

Mobile Sources All nonstationary sources

(mobile and portable) Generally powered by

internal combustion engine Subcategory of area source Generally don’t submit

individual estimates May use a model to estimate

mobile source emissions On-road and non-road

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Types of Sources Included in Eis (cont.)

Biogenic Sources Naturally occurring

emissions Predominantly

VOCs & NOx Widespread areas

Resulting from biological activity Vegetation (trees,

shrubs, grasses, etc.) Microbial

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What does an EI contain? For each source category

Procedures used to collect data Sources of data Copies of questionnaires and results Citations for all emission factors used What methods of calculation were used Documentation of assumptions Listing of sources not included

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Data elements included in an EI Data element: any piece of information

used in EI compilation process EI may have two forms

Narrative report – gives background and explanations

Data set (collection of data elements) – just the facts: numbers, emission factors, default values, calculation equations, etc. Often in database or spreadsheet format

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EI - Required Data Elements Source Identification (ID and name) Source Location (address, geographic

coordinates) Source Description (Stack parameters, capacity) Activity (throughput, temporal data) Controls (equipment type and efficiency) Emissions (amount, methods, pollutants,

emission factors)

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EI – Required Data Elements Data elements used as input for models

Activity data Example: Fleet characteristics and control

measures put into MOBILE model, grams of pollution per vehicle mile traveled comes out of MOBILE model

Emission data Example: emissions & source descriptions from

all sources in given area put into regional air pollution transport model; model predicts where air pollution will travel

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Models used To Create Emissions Estimates

MOBILE6 – calculates emission factors under various conditions (e.g. ambient temp., average traffic speeds) for various vehicle types (light-duty gasoline vehicles, heavy-duty diesel vehicles, etc) Emission factors then used to calculate

emission rates of hydrocarbons, CO and NOx

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Models used To Create Emissions Estimates (cont.) Non Road Model

Estimates emission from non-road engines (airplanes, agricultural vehicles, lawn and garden equipment, construction equipment,etc.)

Inputs include equipment populations Fuel characteristics Ambient temperature

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Models used To Create Emissions Estimates (cont.)

Other models for predicting emission rates Biogenic Emissions Inventory System (BEIS) Highway Vehicle Particulate Emission

Modeling (PART5) TANKS – estimates emissions from organic

liquid storage tanks

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EI – Required Data Elements By being familiar with your EI data...

Calculations and data used to estimate emissions

Equations/methods/models used …you will be familiar with the data that

transport models require as input

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How are EI data used in modeling? Modeling results are only as good as the

data they are based on

EI data is a large part of the data they are based on

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How are EI data used in modeling? More than just emission rates required

Location of source (point sources) Operating data (schedules, throughputs) Process Specifications Emission control information Spatial allocation (emissions assigned to a grid over

the inventoried data (area, mobile, biogenic sources) Temporal allocation (during what time periods do

emissions occur) (area, mobile, biogenic sources)

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EI Data Important to Models Models need process level emissions , the

more detail, the better Not just one emissions number

Ex. Gravel Pit produces 50 tons PM10/year

Break down to process level: 5 tons/year off of storage piles, 30 tons/year from

loading/unloading, 15 tons/year from screening operation.

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EI Data Important to Models (cont.)

EPA Source Classification Codes (SCC) Standard Industrial Classification codes

(SIC) Allows modelers to allocate emissions to

fit their domain, grid scales, time scales, and pollutant speciation if necessary

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EI Data Important to Models (cont.) Need operating schedules

When do emissions occur? Daily Certain hours of the day Monthly Seasonal Annual average

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Temporal Allocation Your EI gives amount of pollutant

emitted from a given source per year Modelers “allocate” emissions to time

period required by their model May convert annual emission rate to daily

or hourly rate

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Pollutant Speciation Pollutants are disaggregated into individual

chemical species based on SCC Used in photochemical, air toxics, and

visibility modeling Hydrocarbons

Benzene, toluene, ethane, etc

NOx NO, NO2

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Spatial Allocation Your EI gives the amount of pollutant emitted

from all area sources across your reservation Modelers allocate emissions to certain grid cells

in their model domain Construction on Res. emits

20 tons/year PM10

5tons/yr

5tons/yr

5tons/yr

5tons/yr

Construction PM10 emissionsAllocated to model grid

20tons/yr

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Why do models need detailed EI data? Detailed data tells the model

Distance of sources from possible receptors Sources may release pollutants only at certain

times of day or during certain seasons of the year

Different source processes have varying chemical reactivities and volatilities

Release heights affect pollution transport and diffusion

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How are EI data used in modeling? Provides starting point

Junk into model = Junk out of model Provides an initial condition/scenario for

the model Give data for what emissions are occurring

where during a base, or starting, year Model calculates forward from the base EI

data

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Summary EI data provides the “facts” about the

present or a past year from which a model will predict the future

Models can be used to provide emission estimates for an EI

Better EI data leads to better model results