How to do an
Emissions Inventory
Mark Gibbs
2015 Emissions Inventory Workshop
2015 Emissions Inventory Workshop 2
Emission Inventory Data Flow
Air Permit Data
Webfire & AP-42 Data
Operation & Production Information
Other Data Sources
Completed Emissions Inventory
Submitted to DEQ
Redbud Hardcopy
TAD
Submit by Mail Submit
Electronically
Key Information - Your Air Permit
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• Permit writer includes initial application data
• Describes operations & processes
• Lists emission units
• Includes emission calculations & references
• Normally lists the acceptable Emission
Factors
Your Permit Memorandum
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Layout of an Inventory • Company – OU Health Sciences Center
• Facility(s) – OKC Campus Services
• Emission unit(s) with release point(s) – Boiler
No. 4 & Boiler No. 4 Stack
• Process(es) – SCC 10300602 =
External Combustion Boilers,
Commercial/Institutional, Natural
Gas, 10-100 million Btu/hr
• Emission(s) – CO, NOx, PM-10, PM-
2.5, SOx, Total VOC, Hexane
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Emission Units
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What is an emission unit?
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What emission units do I report?
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• At least the emission units listed in your permit
• The permit is not the final word for
determining what should be in an
emissions inventory
• The permit may list some processes
as:
But Beware !
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Insignificant for Permitting
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• An emission unit may be insignificant for
permitting, but may not be insignificant
for emissions inventory reporting
• Especially when there are multiple such units
• Are total emissions above the reporting
threshold?
• Contact us to find out about your situation!
What emission units should I report?
Emission Unit Status
• Operating – emission unit operated all or
part of the calendar year.
• Temporarily Shutdown – emission unit
did not operate at all during the calendar
year, but may restart at sometime in the
future.
• Permanently Shutdown – select this status
if an emission unit has been physically
removed or permanently removed from
service.
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Emission Release Points
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Stack Fugitive
Height above ground level
Storage Tank
Pipe work
Minerals
Stack data often listed in the Permit:
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Fugitive Release Points
From Permit:
In Redbud:
Emission Process Information
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Emission Processes
• What information will I need?
– Source Classification Code (SCC)
– Process Material
– Process Rates
– Hours the process ran
– Design capacity (if applicable)
– Fuel data (if applicable)
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Processes – Source Classification Code (SCC)
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• The SCC provides a systematic description of the process
Source Classification Code • You can find the full excel spreadsheet list of SCCs
as well as a 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%20Categories%20SCC_v2004b.pdf
• Description should match operation as
closely as possible
– Be as specific as possible
– Avoid miscellaneous processes (xxxxxx99)
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Process Material, Rate & Hours
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N/A
N/A
Design Capacity & Fuel Data
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Combustion Processes Only
Design Capacity
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From Specific Conditions:
From Permit Memorandum:
Fuel Heat Content
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Other Fuel Data
• Sulfur %: Mass percentage of the
sulfur content in the process fuel
• Ash %: Mass percentage of the ash
content in the process fuel
• For natural gas in Oklahoma report
sulfur & ash percentages as zero
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Emissions Information
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Emissions • What information will I need?
– What pollutants to report
– Method for calculating the emission amounts
(e.g., emission factors)
– Capture efficiency & control efficiency (if
applicable)
– Amount of actual emissions
– 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/
OklahomaRegulatedAirPollutants.htm
• Not sure what pollutants come from your process?
– Look at your permit
– Contact your manufacturer or supplier
– Try entering your SCC into EPA’s WebFIRE database
http://cfpub.epa.gov/webfire/index.cfm?
action=fire.SearchEmissionFactors
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Report all Actual Emissions • "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 OAC 252:100-5-2.1(d).
• Should include
– Regular operations
– Start-up/shutdown/maintenance
– Excess emissions
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Use Best Available Data
• OAC 252:100-5-2.1(d) Method of calculation.
“The best available data at the time the
emission inventory is or should have been
prepared shall be used to determine
emissions.”
• Make sure you are using the most current
emission factors
• Has there been a more recent stack test?
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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
Emissions Calculation Methods
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What is an Emission Factor?
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• An emission factor (EF) relates the quantity of
a pollutant released with an activity or
process rate associated with the release of
that pollutant.
Emissions = Process Rate x EF • Factors are usually expressed as the weight
of pollutant divided by a unit weight,
volume, distance, or duration of the
activity emitting the pollutant.
Emission Factors are often in your permit:
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Emission Factors with Safety Factor Should Not Be Used
• Stack testing plus 25% safety factor
• AP-42, 7/98, Sec. 1.4 plus 25% safety factor
• Baghouse manufacturer guarantee plus safety factor
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Is an Emission Factor Needed?
• Storage Tanks - TANKS
• Tank Flashing - Vasquez-Beggs equation
• Glycol Dehydrator Reboiler - GRI-GLYCalc
• Landfills - LANDGEM, a gas emissions model
These are models
or formulas using multiple variables.
There is no single emission factor.
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No Specific Emission Factor
For the situations on the previous slide & for
complex mass balance calculations enter:
0 * N/A - Formula, Software or CEMS * N/A - Formula, Software or CEMS
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Emission Controls
• Control equipment is
reported for each
individual pollutant
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Controls
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Control Information
• Capture Efficiency - Percentage of air
emissions that are directed to the control
equipment
• Emissions that escape prior to the control
device should be accounted for in the total
actual emissions.
• Control Efficiency - Percentage of air
emissions prevented from being
emitted by a control approach
• Should reflect performance degradation
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Emission Amounts
• What should be reported?
All Actual Emissions
Not Permit limits
or
Potential to
Emit Values (PTE)
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Emissions – Permit/Rule Limit
• If you have a limit for
a particular process,
list it
• Otherwise,
leave it as 0
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• However, ALL actual emissions must be
reported in the total emissions field
• Report quantifiable
emissions that are in
excess of a permit or
other such limit
• Should include total
mass reported under
Subchapter 9 of the
Oklahoma Air Rules
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Report Excess Emissions
Report Excess Emissions
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Total actual emissions of 8.465 tons includes 0.124 tons of excess emissions
0.124 tons represents total mass of all hourly limit exceedances in the reporting year
The annual limit of 11.74 tons has not been exceeded
Why Your Inventory Is Important
• Missing or incorrect release point data
leads to errors in geographical location of
emissions and impacts photochemical
modeling & health risk assessments.
• Missing or incorrect hours & seasonal
fractions lead to errors in temporal
distribution of emissions.
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Why Your Inventory Is Important
• Errors in SCC & SIC impact control
strategy development & 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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