What is an Emissions
Inventory?
By Carrie
Schroeder
“Cheat Sheet” Index Card
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Air Quality 101
Why do you have to
report an emissions
inventory?
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Air Quality 101
Summary of the Clean Air Act
42 U.S.C. §7401 et seq. (1970)
The Clean Air Act (CAA) is the comprehensive federal law that regulates
air emissions from stationary and mobile sources. Among other things,
this law authorizes EPA to establish National Ambient Air Quality
Standards (NAAQS) to protect public health and public welfare and to
regulate emissions of hazardous air pollutants.
One of the goals of the Act was to set and achieve NAAQS in every
state by 1975 in order to address the public health and welfare risks
posed by certain widespread air pollutants. The setting of these
pollutant standards was coupled with directing the states to develop
state implementation plans (SIPs), applicable to appropriate industrial
sources in the state, in order to achieve these standards. The Act was
amended in 1977 and 1990 primarily to set new goals (dates) for
achieving attainment of NAAQS since many areas of the country had
failed to meet the deadlines.
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Air Quality 101
• Our SIP includes the Oklahoma Air Quality Rules
• OAC 252:100-5-2.1. Emission inventory
(a) Requirement to file an emission inventory. The owner or operator of any facility that is a source of regulated air
pollutants shall submit a complete annual emission inventory through DEQ’s electronic reporting system or in
another manner acceptable by the Division.
(1) General requirements. The inventory shall cover operations during a calendar year and shall be submitted on or
before April 1 of the following year. Upon receiving a written demonstration of good cause the Director may grant
an extension for submittal beyond the April 1 deadline.
(2) Permit by rule. The owner or operator of a facility registered under a permit by rule in Subchapter 7, Part 9,
shall submit, at a minimum, an annual emission inventory for the 2014 reporting year or the calendar year in which
the facility is registered, if the facility is registered after December 31, 2014, and thereafter according to the
following schedule:
(A) For a registered facility with actual emissions greater than 5 tons per year of any regulated air pollutant,
an annual emission inventory for that facility shall be submitted every National Emissions Inventory (NEI)
Three-Year Cycle Inventory year, as defined in 40 CFR Section 51.30(b).
(B) For a registered facility with actual emissions of 5 tons per year or less of any regulated air pollutant, an
annual emission inventory for that facility shall be submitted every second National Emissions Inventory (NEI)
Three-Year Cycle Inventory year, as defined in 40 CFR Section 51.30(b), beginning with the 2020 NEI reporting
year.
(3) Permit exempt facilities and de minimis facilities. The owners or operators of permit exempt facilities or de
minimis facilities, as these terms are defined in OAC 252:100-7-1.1, are not required to submit an annual emission
inventory.
(4) Special inventories. Upon request by the Director, the owner or operator of a facility that emits or has the
potential to emit any regulated air pollutant shall file an emission inventory with the Division. The Director is
authorized to request this inventory when emission related data is necessary for program planning or compliance
with State or Federal rules, regulations, standards, or requirements.
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Table 1: Sources, Health and Welfare Effects for Criteria Pollutants
Pollutants
Description
Sources
Health Effects
Welfare Effects
Carbon
Monoxide
(CO)
Colorless,
odorless gas
Motor vehicle exhaust, Indoor
sources include kerosene or
wood burning stoves.
Headaches, reduced mental
Contributes to the
alertness, heart attack,
formation of smog.
cardiovascular diseases, impaired
fetal development, death.
Sulfur Dioxide
(SO2)
Colorless gas that
dissolves in water vapor
to form acid, and interacts
with other gases and
particulates in the air.
Coal-fired power plants,
petroleum refineries,
manufacture of sulfuric acid and
smelting of ores containing
sulfur.
Eye irritation, wheezing, chest
tightness, shortness of breath,
lung damage.
Contributes to the
formation of acid rain,
visibility impairment, plant
and water damage,
aesthetic damage.
Nitrogen Dioxide
(NO2)
Reddish brown, highly
reactive gas.
Motor vehicles, electric utilities,
and other industrial, commercial,
and residential sources that burn
fuels.
Susceptibility to respiratory
infections, irritation of the lung
and respiratory symptoms (e.g.,
cough, chest pain, difficulty
breathing).
Ozone (O3)
Gaseous pollutant when it Vehicle exhaust and certain other Eye and throat irradiation,
is formed in the
fumes. Formed from other air
coughing, respiratory tract
troposphere.
pollutants in the presence of
problems, asthma, lung damage.
sunlight.
Contributes to the
formation of smog, acid
rain, water quality
deterioration, global
warming, and visibility
impairment.
Plant and ecosystem
damage.
Lead (PB)
Metallic element
Particulate Matter Very small particles of
(PM)
soot, dust, or other
matter, including tiny
droplets of liquids.
Metal refineries, lead smelters,
battery manufacturers, iron and
steel producers.
Anemia, high blood pressure,
brain and kidney damage,
neurological disorders, cancer,
lowered IQ.
Affects animals and plants,
affects aquatic ecosystems.
Diesel engines, power plants,
industries, windblown dust,
wood stoves.
Eye irritation, asthma, bronchitis, Visibility impairment,
lung damage, cancer, heavy
atmospheric deposition,
metal poisoning, cardiovascular aesthetic damage.
effects.
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What is an Emissions Inventory
• A report describing what’s going on at
the facility
– Lists equipment/activities and describes the
processes in which emissions are released
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Layout of an Inventory
• Company – University of Oklahoma Health Sciences Center
• Facility(s) – OKC Campus Services
• Emission unit(s) with release point(s) –
Boiler No. 4 & Boiler No. 4 Stack
• Process(es) – Source Classification Code 10300602 =
External Combustion Boilers, Commercial/Institutional,
Natural Gas, 10-100 million Btu/hr
• Emission(s) – CO, NOx, PM-10, PM-2.5,
SOx, non-HAP VOC, Benzene, Formaldehyde,
Hexane, Toluene
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Emission Units
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Emission Units
• What is an emission unit?
Any part of a facility that releases emissions
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Emission Units
• What emission units should I report?
– If it’s in your permit then it should be in your inventory
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Emission Units continued
• What emission units should I report?
– “Insignificant activities” (Appendix I of our Rules)
and “Trivial Activities” (Appendix J of our Rules)
may need to be reported
Call us to find out for your situation!
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Release Points
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Release Points
• What is a release point?
The point or area at which the emissions are
released into the environment
• Common types are fugitive, vertical stack,
horizontal stack
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Release Points
Stacks
Fugitives
Pipe work
Storage Tank
Minerals
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Processes
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Processes
• What information will I need?
–Source Classification Code
–Process Material
–Process Rate
–Hours the process ran
–Design capacity (if applicable)
–Fuel data (if applicable)
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Processes – Source Classification Code
• Describes the process in which pollutants are emitted
• You can find the full excel spreadsheet list of SCCs as
well as the smaller table just showing the first 3
digits of the SCCs on our website:
– http://www.deq.state.ok.us/aqdnew/emissions/TurnAroundDocs.htm
– http://www.deq.state.ok.us/aqdnew/emissions/Point%20Source%20Cate
gories%20SCC_v2004b.pdf
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Processes – Material, Rate, Hours
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Emissions
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Emissions
• What information will I need?
– What pollutants to report
– Method for calculating the emission amounts
(emission factor)
– Control efficiency and capture efficiency (if
applicable)
– Permit or rule limit (if applicable)
– Excess emissions (if applicable)
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Emissions
• Report Regulated Air Pollutants (RAPs) – pollutants
regulated by statute, rule, regulation or permit
http://www.deq.state.ok.us/aqdnew/emissions/OklahomaRegulatedAir
Pollutants.htm
• Not sure what pollutants come from your process?
– Look at your permit
– Contact the manufacturer, ask your supplier
– Try entering your SCC into EPA’s WebFIRE database
http://cfpub.epa.gov/webfire/index.cfm?action=fire.SearchEmissionFactors
• "Actual emissions" means the total amount of any
regulated air pollutant actually emitted from a given
facility during a particular calendar year, determined using
methods contained in 252:100-5-2.1(d).
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Emissions – Calculation Methods
Approximate Ranking of Reliability:
Continuous Emissions Monitoring Data (CEMS)
EPA RM Stack Test
Similar Unit EPA RM Test
Mass Balance
Manufacture Test Data
TANKS, GRI-GLYCalc, Vasquez-Beggs
WebFIRE Data Factors
AP-42, other EPA Documents
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Emissions – Emission Factor
• What emission factor (EF) should be reported?
– If your calculation method uses a single factor, enter that EF
– If your method uses a complex formula or model, list the
factor as 0 and the units as *NA/*NA
• Some methods that may use a model or
complex equations:
–
–
–
–
Storage Tanks – TANKS, Vasquez-Beggs equation
Glycol Dehydrator Reboiler - GRI-GLYCalc
Mass Balance
EPA documents with formulas
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Emissions – Emission Factor
For the situations on the previous slide and for complex
mass balance calculations enter:
0
* N/A - Formula, Software or CEMS
* N/A - Formula, Software or CEMS
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Resources for Emission Factors
• WebFIRE –
http://cfpub.epa.gov/webfire/index.cfm
• AP-42 http://www.epa.gov/ttn/chief/ap42/index.html
• TANKS http://www.epa.gov/ttnchie1/software/tanks
• Vasquez-Beggs www.deq.state.ok.us/aqdnew/resources/Calculati
ons11.xls
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• PM-10 – all particulate matter with an
aerodynamic diameter equal to or less than 10
micrometers
• PM-2.5 – all particulate matter with an
aerodynamic diameter equal to or less than 2.5
micrometers
Amt
0
10
Size (microns)
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Emissions – Particulate Matter
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Calculated Emissions
What should be reported?
All Actual Emissions
not
Permit limits
or
Potential to Emit Values (PTE)
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Emissions - Controls
• Control equipment is
reported at the pollutant
level
Emissions –
Controls
• Control Scenario – control system, abatement equipment or
approach applied to reduce emissions of the pollutant
• Capture Efficiency – the percentage of air emissions that is directed
to the control equipment, or an estimate of that portion of an
affected emissions stream that is collected and routed to the
control measure, when the capture or collection system is operating
as designed
• Control Efficiency – the percentage of actual air emissions
prevented from being emitted by the control scenario. The actual
efficiency should reflect control equipment downtime and
maintenance degradation
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Emissions – Permit/Rule Limit
• If you have a limit, list it
• Otherwise, leave it as 0
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Yes, Report the following:
• Quantifiable emissions
that are in excess of a
permit or other such
limit
•
Should include total mass
reported under Subchapter 9 of
Oklahoma Air Rules
• However, ALL actual emissions must be
reported in the total emissions field
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Why Your Inventory Is Important
• Missing or incorrect release point data leads to errors in
geographical location of emissions and impacts
photochemical modeling and health risk assessments.
• Missing or incorrect hours and season fractions lead to
errors in temporal distribution of emissions.
• Errors in SCC and SIC impact control strategy
development and attainment plans.
• Missing or incorrect control equipment data impacts
rule development.
• Good data leads to effective air quality regulation.
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Questions?
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