Emission Inventories and EI Data Sets Sarah Kelly, ITEP Les Benedict, St. Regis Mohawk Tribe

2 Emission Inventories and EI Data Sets What is an emissions inventory? How are EI data used in modeling?

3 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

4 How are EIs used in modeling? Starting point for modeling Provides other data needed for model Activity data Time period of air pollutant emissions

5 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?

6 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

7 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

8 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

9 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

10 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

11 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

12 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)

13 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

14 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

15 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

16 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

17 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

18 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

19 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)

20 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 PM 10 /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.

21 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

22 EI Data Important to Models (cont.) Need operating schedules When do emissions occur? Daily Certain hours of the day Monthly Seasonal Annual average

23 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

24 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, NO 2

25 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 PM 10 5 tons/yr 5 tons/yr 5 tons/yr 5 tons/yr Construction PM10 emissions Allocated to model grid 20 tons/yr

26 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

27 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

28 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