Do I Need an AQMD Permit? Applicability Determinations Explained
Most California facilities we walk into are not sure whether they need an air permit.
Most California facilities we walk into are not sure whether they need an air permit. They use solvents, run a small boiler, maybe operate a heated dip tank, and the question hangs over the operation: are we supposed to have a permit for this, or not?
That uncertainty is the most common air-compliance question we hear. It usually sounds like this: “We use products with VOCs, and while I believe we are below permitting thresholds, I am uncertain.” It is the right question to ask before someone else asks it for you.
This piece explains how an applicability determination works, the thresholds and exemptions that typically decide the answer, and how to engage on the question without committing to a full permit application up front. For the wider context on California air permitting, see our air quality compliance in California guide.
What an Applicability Determination Is
An applicability determination, sometimes called a rule evaluation, is a focused review of your operations against the rules of your local Air Quality Management District. The output is a written answer to one question: do you need a permit, and for what?
In California, air permitting is administered by 35 regional air districts. Each district has its own rules, exemptions, and thresholds. The four districts we work in most often are:
- BAAQMD (Bay Area Air Quality Management District)
- SCAQMD (South Coast Air Quality Management District)
- SJVAPCD (San Joaquin Valley Air Pollution Control District)
- Sacramento Metropolitan Air Quality Management District
The California Air Resources Board (CARB) sits above the districts and the federal Clean Air Act sits underneath, but the rules that decide whether your specific equipment needs a permit live at the district level. That is why an applicability determination has to be done against the right district’s rule set, not a generic federal checklist.
A rule evaluation reviews equipment specs, the chemicals in use, throughput, and proximity factors against the applicable district rules. If a permit is required, the deliverable scopes the application. If no permit is required, the deliverable is a written confirmation letter you can keep on file when an inspector asks.
Signs You May Need an Air Permit
When we walk a facility for the first time, these are the things that usually trigger a closer look. If any of these describe your operation, an applicability determination is the right next step.
- Painting, spray booths, or surface coating of any kind, including powder coating prep
- Printing operations (lithographic, screen, flexographic, digital with solvent inks)
- Wipe cleaning with solvents above roughly 20 gallons per year (the BAAQMD exemption threshold under Regulation 2, Rule 1; check your specific district)
- Heated plating or anodizing tanks, especially with cadmium, hex chrome, nickel, or lead
- Abrasive blasting or grit blasting, including equipment inherited from a prior tenant
- Boilers, ovens, dryers, and combustion sources above 1 million BTU/hr (or above 10 million BTU/hr for natural gas in BAAQMD, with a registered boiler step in between)
- Internal combustion engines above the district exemption (engines rated above 50 brake horsepower in both SCAQMD and BAAQMD)
- Storage tanks holding solvents, fuels, or certain organic liquids
- Abatement devices (scrubbers, dust collectors, thermal oxidizers)
- Significant epoxy, glue, or adhesive use
- Any process using more than 20 gallons per year of materials containing volatile organic compounds (VOCs)
Two situations push this from “should look into it” to “look into it now”:
New equipment going in.
District rules require an Authority to Construct before installation in most cases. Installing first and asking later is how facilities end up with enforcement letters.
Equipment you inherited.
Ownership changes, tenant turnover, or acquisitions routinely leave equipment running with no permit assigned to the current operator. The longest case we have walked into was a shot-blasting machine that had been running for twenty years with no air permit on file. That kind of gap is easier to regularize when the facility discovers it than when the district does.
How District Exemptions Actually Work
Most facilities assume “we are under the threshold” without ever putting numbers on paper. The exemptions are real but narrow, and they read differently district to district.
A few examples of the kind of exemption language we work through:
- Wipe cleaning under 20 gallons per year of solvent or 150 pounds per year of VOC is exempt under BAAQMD Regulation 2, Rule 1, Section 118.9. SCAQMD has its own equivalent under Rule 219.
- Acetone has been classified as an exempt solvent in most California districts since 1996, but only when used as a substitute, not stacked on top of other VOC use.
- Hand-held aerosol cans are exempt, but only the non-refillable type.
- Combustion sources under 1 MM BTU/hr are typically exempt; natural gas units up to 10 MM BTU/hr may also be exempt, but 2 to 10 MM BTU/hr units in BAAQMD require a registered boiler, which is its own paperwork.
- Internal combustion engines rated 50 brake horsepower or less are exempt in both SCAQMD (Rule 219) and BAAQMD; larger engines require a permit, and use patterns can still trigger registration or other rules.
- Coffee roasters under 15 lb/hr are exempt under BAAQMD.
- Electrolytic plating with certain metals is exempt under BAAQMD but not under SCAQMD for the same metals.
The pattern: district rules look similar in outline and differ in the details. An exemption that applies at one facility in Hayward will not necessarily apply at the same operation in Vernon. That is the work an applicability determination does.
The Two-Stage, Low-Commitment Path
For most facilities, we recommend handling this in two stages.
Stage 1: Rule evaluation.
Fixed-price, defined scope. You provide equipment specifications, Safety Data Sheets (SDSs) for the chemicals in use, throughput data, and a description of the operation. We review against the relevant district rules and tell you in writing whether a permit is required. If the answer is no, you get a confirmation letter. If the answer is yes, you get a scoped recommendation for the application.
Stage 2: Permit application, only if required.
Authority to Construct first, then Permit to Operate after installation. We handle the district forms (Form P-101B and the source-specific forms in BAAQMD, the 400-series in SCAQMD), the emissions calculations, the site maps, the SDS package, and the back-and-forth with the district engineer. For the full walk-through of that stage, see how to get an air quality permit in California.
Splitting it this way means you do not commit to the cost of a full permit application until you know one is needed. If you do already know an unpermitted source is running, the path back to compliance starts the same way; see operating without an air permit for what that looks like.
What We Need to Give You an Answer
The faster you can put your hands on the following, the faster the rule evaluation produces a useful result:
- Equipment make, model, capacity, and operating hours
- SDSs for every chemical in the process
- Annual usage quantities (gallons, pounds, hours of operation)
- Any existing air permits and any prior Notices of Violation
- A facility map showing where the equipment sits
- Distance to the nearest school (this matters for downstream public-notification rules)
- Abatement device information, if any (make, model, capacity, efficiency)
You do not need all of it perfect on day one. Gaps in equipment data are common, particularly for older sources. We document our assumptions when we have to make them, and we tell the district what we assumed.
Closing the Question Before It Becomes a Problem
The reason to settle this before a deadline or an inspection forces it: the cost of an unpermitted source discovered by the district is almost always higher than the cost of permitting it cleanly. District timelines for new permits run 6 to 9 months in Southern California. Working from a deadline shrinks your options.
Coating or painting on site? Air permits for spray booths and surface coating operations →
Trusted throughout California
BSY started working with CDMS last year after our in-house EHS person departed the company. CDMS reviewed our existing operational permits as well as any additional Federal, State and Local regulations that could apply and helped us to create a comprehensive compliance calendar to track regulatory deadlines and submittal due dates. The CDMS team does an excellent job of tracking everything and can be relied upon to complete the forms accurately and assist with submittals, allowing me to focus on our business.
Speak with a CDMS EHS expert
Tell us about your facility and your deadline. You’ll get a clear read on what applies and a scoped plan to handle it.