Practitioner tools
Tools for the Problems You Hit Every Week
Start from the problem
Are we going to bust a 12-month rolling limit, and how much room is left next month?
Rolling 12-Month Limit TrackerTrack any 12-month rolling sum or average against a permit limit. See every window, the months that drive it, next month's headroom, and when a forecast crosses the limit.OpenIs this project a major modification? Which 24-month baseline period helps us most?
NSR Baseline & Project Emissions CalculatorFind the highest eligible consecutive 24-month baseline across all units in a project, then run the actual-to-projected-actual and hybrid tests against the significance value you enter.OpenHow do I turn a 150-page operating permit into tracked tasks with owners?
Permit Compliance Matrix BuilderPaste permit conditions. Get a compliance matrix with suggested requirement types, frequencies, citations, and deadline phrases, then export it or send dates to the Compliance Calendar.OpenWhat deviated this reporting period, why, and did we report it?
Title V Deviation LogLog deviations as they happen with cause, corrective action, and prompt-report dates. Entries group by your permit's reporting periods and export for the semiannual report.OpenThe test report is in ppm at measured O2. The permit limit is in lb/hr or lb/MMBtu.
Stack Test & Unit Convertersppm to lb/hr, O2 correction, ppm to lb/MMBtu with F-factors, g/hp-hr, tons per year, mg/m³, and wet to dry, with every step shown.OpenWhat did EPA publish this week, and which comment periods are closing?
Federal Air Rule TrackerNew EPA final and proposed rules for NSPS, NESHAP, SIPs, Title V, GHG reporting, and NAAQS, pulled from the Federal Register with comment deadlines.OpenWhat exactly does “potential to emit” or “major modification” mean, and where is it defined?
Air Permitting GlossaryPlain-language definitions of air permitting terms, each linked to the regulation that defines it.Open
Stack test and unit converters
The conversions you do between a test report, a CEMS printout, and a permit limit. Every step is shown, and nothing regulatory is prefilled.
- ppm to lb/hrConvert a stack gas concentration in ppmv to a mass emission rate in lb/hr, or back, using stack flow and molecular weight. Shows every step.
- O2 correctionCorrect a measured concentration to a reference oxygen level such as 3%, 7%, or 15% O2 using the 20.9 correction. Shows the formula and steps.
- ppm to lb/MMBtuConvert ppmvd at a measured O2 to lb/MMBtu with an oxygen-based F-factor (Fd), or back. Formula, steps, and Method 19 reference shown.
- lb/MMBtu to lb/hrConvert a heat-input emission factor in lb/MMBtu to lb/hr and tons/yr from firing rate, or from fuel use and heating value.
- g/hp-hr to lb/hrConvert engine emission factors between g/bhp-hr and lb/hr, with tons per year at the hours you enter.
- lb/hr to tons/yrConvert an hourly emission rate to tons per year at the operating hours you enter, or back from tons per year to lb/hr.
- ppm to mg/m³Convert gas concentrations between ppmv and mg/m³ at the temperature and pressure you choose.
- Wet to dry basisConvert a stack concentration between wet and dry basis using the moisture fraction (Bws).
How these tools are built
The math is on the page
Every result lists its formula and each intermediate step, so you can check it by hand or hand it to a reviewer.
Rule text, not paraphrase
Where a tool follows a regulation, the governing words are quoted from a government source with the citation. You enter the regulatory values from the rule that applies to you.
Your data stays with you
Entries are kept in your browser, not sent to AirPermitHub. Export to CSV to keep a record or share it with your team.
Guides for the hard parts
- Compliance · 7 min readTracking a 12-month rolling limit without surprisesHow to read a rolling limit, build the monthly calculation once, and watch next month's headroom so a synthetic minor limit never catches you late.
- Federal Regulations · 9 min readChoosing a baseline period for NSR project emissions accountingHow baseline actual emissions work, the rules on which months you can use, and how to pick and document the period before calculating a project's emissions increase.
- Compliance · 8 min readBuilding a Title V compliance matrix that holds up in an inspectionBreak the permit into individual requirements, give each one an owner, a frequency, and a record, and keep the matrix current through every permit revision.
- Compliance · 7 min readDeviation reporting: what to capture while it's freshWhat counts as a deviation, how prompt and periodic reporting fit together, and the details to record on the day so the report writes itself.
- Emission Calculations · 8 min readStack test results: correcting to reference O2 and converting unitsHow to put test results on the same basis as the permit limit: dry versus wet, oxygen correction, mass rates, and lb/MMBtu with F-factors.
- Compliance · 8 min readPreparing for a performance test: a practitioner's checklistNotifications, test plans, operating conditions, sampling access, and what to do when a run fails, with the general provisions to read for each step.
Also on AirPermitHub
AirPermitHub provides educational, engineering, research, and compliance-support information. Information provided by the platform does not constitute legal advice and should not replace review of applicable regulations, permits, agency guidance, or consultation with qualified professionals. Full disclaimer