What Did MethaneAIR Find? Methane 5x Above EPA in 12 Basins
MethaneAIR flights over 12 US basins in 2023 found about 7.9 million tonnes a year of oil and gas methane, about 5x EPA's estimate. Basin-by-basin results.
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Emission Factors, Calculations and Air Permits
Most oil and gas emissions are calculated rather than measured, and the result depends on the emission factor, the model and the assumptions behind it. EPA's AP-42 compilation is the most common source of factors, and its ratings say how far each one can be trusted.
These posts cover emission factors and where they come from, how to calculate emissions from storage tanks, glycol dehydrators, pneumatic devices, flares and engines, how stack testing and continuous monitoring check the numbers, and the air permits, from permits by rule to Title V, and spill prevention plans that depend on them.
The calculation posts work from the inputs an operator actually has, name the factor or model they use, and say what the result is most sensitive to. The free calculators on the site follow the same rule and show every factor they apply.
27 posts in this topic
Oil and Gas Due Diligence Checklist: 10 Regulatory Records
Oil and gas due diligence checklist: the 10 regulatory records, from operator, wells and production to spills, enforcement, emissions, plugging and injection.
Oil and Gas Permit Requirements: Every Permit and Plan
The permits and plans a US oil and gas well site or compressor station needs: who issues each, what triggers it, and the order to get them in.
What Is Emissions Intelligence for Oil and Gas Methane?
Emissions intelligence joins reported, modelled and measured methane to the assets behind it: why the three disagree and how OGMP 2.0 reconciles them.
Oil and Gas Production Data: How to Find It in Eight States
Look up oil and gas production data by well, API number, operator and county in eight states, and see how far back each state's production history goes.
Oil and Gas Data Analytics Platforms: How to Choose One
An oil and gas data analytics platform should fit your states and your job. Five kinds compared, what each leaves you to do, and how to test one in a trial.
EHS Management Software and What It Cannot Compute
EHS software is a system of record. It handles the documents and dates well, and stores whatever emissions number you give it rather than deriving one.
Default Emission Factors: When Subpart W Still Allows Them
Default emission factors are Subpart W's Calculation Method 4 for natural gas pneumatic devices, and cannot be used for devices measured under Methods 1 to 3.
OOOOb Compliance Software: What to Track and How to Choose
OOOOb sets six survey frequencies and two repair clocks by site type, and the rule is under reconsideration. Here is what to track and how to evaluate tools.
Continuous Emission Monitoring Systems: When CEMS Apply
A CEMS is a certification regime, not a sensor. Which oil and gas equipment needs one, what changed for turbines in 2026, and the quarterly cost.
New Mexico Ozone Season O&G Rules: NMED Requirements
NMED 20.2.82 NMAC requires heightened LDAR surveys and equipment controls for New Mexico oil and gas facilities during the May through October ozone season.
SPCC Plan Requirements: The 1,320 Gallon Threshold and Tiers
SPCC applies above 1,320 gallons of aboveground oil in 55 gallon or larger containers. At 10,000 gallons or less with a clean record, you can self-certify.
Title V and PSD Thresholds: Which Air Quality Permit Applies
Which air permit applies turns on potential to emit: Title V at 100 tpy, PSD at 100 or 250 tpy, lower in nonattainment areas, and the oil and gas site rules.
Natural Gas BTU: Wellhead Gas vs the 1,020 Btu Standard
Pipeline gas is assumed at about 1,020 Btu per cubic foot. Across 31,823 wellhead analyses, 79 per cent sit at or above it, with state medians up to 1,206.
Oil and Gas Flaring: What Flares Actually Destroy
AP-42 assumes 98% destruction and publishes no methane factor. What Subpart W requires instead, plus measured values from 99.8% down to 91.1%.
What Is Stack Testing? Methods, Rules, and Its Limits
Stack testing measures pollutant concentration and flow at one outlet under representative conditions. What the methods cover and what a result cannot show.
AP-42 Emission Factors: Gas Engines, Turbines, Boilers, Flares
AP-42 NOx, CO, VOC and methane factors for natural gas engines, turbines, boilers and flares, with table numbers, A to E ratings, and what each factor assumes.
AERMOD Emission Rates: Where the Numbers Come From
AERMOD takes an emission rate as an input and never calculates it. Where that number comes from, what AP-42 factors assume, and when it matters.
Storage Tank Emissions Calculation: Formulas and Failures
Standing, working, and flashing losses are the standard tank emissions calculation. What the formulas cover, where they stop, and what failure adds.
EPA's April 2026 OOOOb/OOOOc Amendment: What Changed
EPA revised OOOOb/OOOOc temporary flaring and NHV monitoring, effective June 8, 2026. Most flares and combustion devices are now exempt from NHV monitoring.
Colorado Oil & Gas Map: Emissions and Enforcement Data
Search 40,000+ Colorado oil and gas wells on one map, cross-linked with production, emissions, and enforcement from ECMC and CDPHE records. Try it free.
Glycol Pumps: 90% of Modeled Emissions at Six TEG Dehydrators
A mechanistic TEG dehydrator model attributed 90.25% of dehydrator emissions at six units with gas-assisted pumps and uncontrolled flash tanks to the pumps.
Colorado Regulation 7: GHG Intensity Verification Factor
How Colorado Reg 7 Section VIII scales ONGAEIR methane: CDPHE's factor rose from 1.164 (2025) to 2.2-2.7 by region (2026); targets run through 2030.
How to Get a Colorado Operator-Specific Verification Factor
How Colorado operators replace the state default verification factor with an operator-specific one under Reg 7 Part B Section VIII, and when it pays off.
Colorado ONGAEIR Due June 30: A Practical Filing Checklist
Colorado ONGAEIR report for CY2025 is due June 30, 2026. Which facilities must report, required source categories, and a pre-submission checklist for operators.
Subpart W Proposed Rule: Is GHGRP Reporting Still Required?
The Subpart W proposed rule (90 FR 44591) would pause reporting through RY2034, but it is not final. Facilities still file RY2025 data by March 10, 2027.
GHGRP Subpart W Deadline Moved to March 10, 2027
EPA moved the RY2025 GHGRP filing deadline to March 10, 2027, while a separate proposal to suspend Subpart W reporting through 2034 remains pending.