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.
← All posts
TOPIC
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.
21 posts in this topic
Default Emission Factors: Subpart W Bars Them for Pneumatics
Default emission factors are Subpart W's last-ranked method for natural gas pneumatic devices, and are barred outright at sites with a supply-line flow meter.
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: Do You Need One, and Which Tier?
SPCC applies above 1,320 gallons of aboveground oil storage. The capacity and discharge tests that decide whether you can self-certify or need an engineer.
Air Quality Permit Types: Title V, PSD, and Their Thresholds
Which air permit applies depends on your potential to emit. The Title V and PSD thresholds, the oil and gas aggregation rules, and where the numbers come from.
Natural Gas BTU: What Wellhead Gas Actually Measures
Pipeline gas runs near 1,020 Btu per cubic foot. Wellhead gas runs higher. Measured heating values across eight states, and which calculations they change.
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 by Source Type, and What They Assume
AP-42 emission factors for boilers, turbines, engines, and flares, with the A to E ratings, plus the operating assumption built into every factor.
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 Uncontrolled TEG Dehydrator Emissions
A mechanistic model of TEG dehydrator emissions finds gas-assisted glycol pumps produce about 90% of uncontrolled methane, reframing control priorities.
Colorado Regulation 7: GHG Intensity Verification Factor
How Colorado Regulation 7 Part B Section VIII scales ONGAEIR methane by CDPHE's 2025 verification factor of 1.164, plus the intensity targets 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.
GHGRP Subpart W Reporting in 2026: What Is Still Required
GHGRP Subpart W reporting remains mandatory in 2026. The RY2025 deadline moved to October 30, 2026. Here is what changed, what did not, and what to file.
GHGRP Subpart W Deadline Moved to October 2026
EPA moved the RY2025 GHGRP filing deadline to October 30, 2026, while a separate proposal to suspend Subpart W reporting through 2034 remains pending.