Emissions Inventory
Overview–Part 1
Melinda Ronca-Battista, ITEP
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Overview
What is an Emissions Inventory and why
do we need one?
 Part 1

◦ Types of EIs
◦ Pollutants
◦ Sources

Part 2
◦ Quantifying emissions
◦ Types of data collected
◦ Reporting
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What is an Emissions Inventory?
Listing of sources of
estimated air pollutant
emissions in geographic area
during specific time period
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What are Emission Sources?
Non-Point
Sources (Area
Sources)
Non-Road
Mobile
Sources
Point Sources
On-Road
Mobile
Sources
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Based on EPA
How are EI data used?

Air quality management tool
◦ Collect baseline data
◦ Develop & track emissions control and management strategies
Regulations development
 Air quality modeling and assessment
 Permits

◦ Do you have facilities that need permits?
◦ Conditions (potential to emit)
◦ Fees


Emissions trading
Regulatory compliance
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Inventory Steps

Source identification
◦ Phonebook/windshield survey
◦ NEI data, previous EIs

Planning!
◦ Inventory Preparation Plan (IPP)
◦ Quality Assurance Project Plan (QAPP)

Collect data
◦ From sources, permits, questionnaires, etc.
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Inventory Steps (cont.)
Calculate and analyze data (TEISS, Excel,
GIS, etc.)
 Report data and present results

◦ Internal: tribal council, community
◦ External: EPA project officer, National
Emissions Inventory (NEI)
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Level of Detail

Simple summary: Small reservation, few
on-reservation sources
◦ Compiled from existing data sources
◦ Includes only large sources

Comprehensive accounting: Large
reservation, many and/or large sources
◦ Large on-reservation sources–permitting
◦ “Problem” emissions (agricultural burning,
small industries, road dust, traffic emissions)
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What are Emissions?

Criteria Pollutants
◦
◦
◦
◦
◦

Particle matter: PM10 and PM2.5
Nitrogen oxides: NOx
Sulfur dioxide: SO2
Carbon monoxide: CO
Lead: Pb
Ozone precursors
◦ Ammonia: NH3
◦ Volatile Organic Compounds: VOCs

HAPs (Air Toxics)
◦ 187 toxic, carcinogenic compounds without regulated
standards
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Criteria Pollutants
 What
about Ozone?
◦ Ozone is not emitted directly by sources
◦ EIs inventory ozone precursors
 VOCs
 NOx
 Both react with sunlight to form ozone.
◦ NOx and VOCs get inventoried, but not
ozone itself
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HAPs (Air Toxics)

187 compounds listed in CAA including
◦
◦
◦
◦
◦
Mercury (power plants, coal-fired)
Perchloroethylene (dry cleaning)
Benzene (gasoline)
Chloroform (chlorination plants, paper mills)
Methyl Isocyanate (pesticide manufacturing)
 Release at Bhopal, India, killed 4,000 people
◦ The list goes on….
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Types of Sources
 Point
sources = Stationary
sources
 Area sources = Non-Point
sources
 Mobile sources
◦ On-Road (cars, motorcycles,
trucks, buses)
◦ Non-Road (trains, heavy equip.)
 Biogenic
sources
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What is a Point Source?
Individual, stationary source releasing
pollutants to atmosphere
 Quantities above emission threshold
 Emission thresholds vary according to
type of pollutant and non-attainment area
classification for criteria pollutants
 See Air Emission Reporting Requirement
(AERR) for more detail

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What is a Point Source? (cont.)
AERR reporting thresholds are quite high.
Compared to Potential to Emit.
 Many states have lower thresholds
 Consider using state thresholds to define
your reservation’s point sources

◦ Makes EI compatible with others in your area
◦ Get a more detailed listing of sources
 Example: Busy gas station can be point source
under state thresholds, but not EPA’s
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Example: Point Source Thresholds
Pollutant
Lead (Pb)
PM10
PM2.5
Nitrogen Oxides
(NOx)
Carbon Monoxide
(CO)
Volatile Organic
Compounds (VOC)
EPA’s AERR
Reporting
Thresholds
≥5 ton per year
(tpy)
≥100 tpy
New Mexico
Reporting
Thresholds
>1 ton per
year (tpy)
>10 tpy
≥100 tpy
≥100 tpy
>10 tpy
>10 tpy
≥1000 tpy
>10 tpy
≥100 tpy
>10 tpy
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Point Source Characteristics
 Large, stationary
sources
◦ Manufacturing or production plants
◦ Power plants, refineries
◦ Large, industrial facilities
 One
point source facility can have
emissions from
◦ Smoke stacks
◦ Units within directed to stacks
◦ Fugitive sources within plant
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Point Sources (cont.)
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Area (Non-Point) Sources

Stationary sources that emit
◦ Less than point source threshold
◦ Smaller emitters, but numerous
◦ Often have fugitive
(uncontrollable) emissions

Tend to be sources like
 Gasoline stations
 Dry cleaners
 Auto body/paint shops
 Unpaved roads
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Other Area Sources

Wildfires and prescribed burning
◦ E.g., agricultural field burning
◦ Now inventoried as EVENTS

Other area source examples
◦ Residential wood combustion
◦ Residential combustion of
household waste (backyard burning)
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On-Road Mobile Sources

Vehicles found on roads and highways
(e.g., cars, trucks, buses, motorcycles)
◦ 20 volatile organic compounds (VOCs) and
metals quantified (Urban Air Toxics)
◦ Diesel particulate matter and diesel exhaust
organic gases also quantified
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Non-Road Mobile Sources

Mobile sources not found on roads and
highways (e.g., airplanes, trains, lawn mowers,
construction vehicles, farm machinery)
 2/4 stroke engines
 aircraft
 locomotives
 commercial marine vessels
 hobby engines
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Non-Road Mobile Sources

Note about aircraft
◦ ALL airports are now considered point
sources in the NEI
◦ If you have airports on your reservation,
check the most recent NEI data. Use it in
your EI
◦ UNLESS you have more accurate data.
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Biogenic Sources

Naturally occurring emissions
◦ Vegetation: Trees, shrubs, grasses
◦ Microbial: Soil bacteria, termites
EPA estimates these emissions on a
county level for entire country…
 …so you don’t have to

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