Post on 04-Jan-2016
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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