California Air Permit Application: From ATC to PTO
If a piece of equipment at your California facility is going to emit something into the air, you go to the local air district before you install it.
If a piece of equipment at your California facility is going to emit something into the air, you go to the local air district before you install it. That is the short version. The longer version is two permits, one application packet that runs to dozens of pages, and a district review timeline that often takes longer than the install itself.
This piece walks through how an air permit application actually moves from a new piece of equipment to a final Permit to Operate (PTO). For where this work sits in the wider program, see our air quality compliance in California guide. If you have not yet confirmed whether your equipment even needs a permit, start with applicability determinations.
The Two Permits Behind One Process
California air districts issue permits in two stages. Facilities tend to think of it as one permit; the district handles it as two.
- Authority to Construct (ATC): Issued before installation. The district reviews equipment specs, materials, emissions calculations, and site layout, then confirms in writing that the source can be built and operated within district rules. You do not install before the ATC is in hand.
- Permit to Operate (PTO): Issued after installation, once the district confirms the equipment matches what was approved in the ATC. The PTO is the document you keep on file and present during inspections. PTOs are renewed annually.
- Certificate of Exemption: Issued by some districts (BAAQMD on request) when a piece of equipment does not require a permit. Not required, but useful to have on file when an inspector asks.
For a small number of California facilities that hit federal major source thresholds, a Title V operating permit adds a federal operating-permit layer on top of district permitting, consolidating the applicable Clean Air Act requirements into one permit. It does not replace the district Authority to Construct and Permit to Operate steps for new or modified equipment. Most facilities never trigger Title V.
The Application Process, Step by Step
Each district handles the paperwork differently, but the path is the same. The full sequence we walk facilities through:
Applicability determination.
A focused review of your operations against district rules to confirm which sources actually need a permit. The output is either a confirmation letter (no permit needed) or a scoped recommendation for the application. This stage is fixed-price.
Site visit and data collection.
We come to the facility, walk every potential source, photograph equipment, take measurements, and pull the documentation needed for the packet. New equipment that has not yet been installed is documented from spec sheets and operations manuals.
Form preparation.
District-specific forms are filled out source by source. BAAQMD uses Form P-101B with source-specific attachments. SCAQMD uses the 400-series. Emissions calculations are run on the materials and throughput you provided, against published emission factors where available.
Internal review.
The packet is checked for completeness against district instructions. Where equipment data is missing or unavailable, we document the engineering assumptions we made so the district can see exactly how we got there.
Submittal to the district.
Two copies of the packet go to you: one to sign and submit, one to keep on site. The application fee check is included (mailed to the SCAQMD office in Diamond Bar for South Coast filings).
District review and follow-up.
The district engineer reviews the packet and almost always sends comments or requests for additional information. We respond directly to the engineer, supply what is requested, and track the file through to issuance.
ATC issued. Equipment installed.
The Authority to Construct is the green light to install. Installation is documented for the next step.
PTO issued.
After installation, the district confirms the source matches the ATC and issues the Permit to Operate. The PTO renews annually after that.
In Southern California, that full sequence typically runs six to nine months from submission to PTO. Application preparation is much faster than district review; the constraint is agency capacity, not packet readiness.
What a BAAQMD Application Packet Contains
For a Bay Area filing, the packet is built around Form P-101B with whichever source-specific forms apply to your equipment. The most common attachments:
| Source-specific form | What it covers |
|---|---|
| Combustion Form | for boilers, furnaces, ovens, dryers, and other fuel-burning sources |
| Abatement Device Form | for scrubbers, dust collectors, thermal oxidizers, and other control equipment |
| Surface Coating Form | for paint booths, spray operations, and powder-coating prep |
| Solvent Cleaning Form | for wipe cleaning, vapor degreasing, and parts washing above threshold |
| Organic Storage Form | for tanks holding solvents, fuels, or other organic liquids |
| Semiconductor Form | for wafer fabrication operations |
| Emission Point Form | for stacks and vents |
The packet also includes a project description, an equipment description, a Google map of the property, a facility map showing equipment and stack locations, the full Safety Data Sheet (SDS) set for the materials in the process, and the cover and exemption letters the district expects to see.
What an SCAQMD Application Packet Contains
For a South Coast filing, the 400-series forms drive the packet:
- Form 400-CEQA for the California Environmental Quality Act notification step
- Form 400-PS for the permit application summary
- Forms 400-A and 400-E (with source-specific suffixes) for each piece of equipment
- SDSs for the materials in use
- Application fee check mailed to the district office in Diamond Bar
Specific rules referenced inside the packet vary by source: Rule 219 (exemptions), Rule 1401 (new source review for toxic air contaminants), Rule 1469 (hexavalent chromium plating), and others depending on the equipment.
What We Need From You
A complete packet starts with the data we collect at the site visit. The more of this you can pull together before we walk the facility, the faster the application moves:
- Equipment information: make, model, capacity, throughput, install date (or planned install date), and equipment cost
- Process materials: SDSs for every chemical in the process and annual usage in pounds or gallons
- Process detail: operation description, hours of operation, batch or continuous, abatement device make/model/capacity/efficiency
- Engineering data: air flow (CFM), vent diameters, stack heights, tank dimensions, freeboard, heating and agitation details for plating tanks
- Site documentation: facility map showing equipment and stack locations (8.5 x 11 sheets are fine), a Google map of the property, distance to the nearest school
- Compliance history: existing air permits at the facility and any Notices of Violation on record
Older equipment without published emission data is normal. We work from documented engineering assumptions in that case and call them out so the district reviewer can see how each emission number was derived.
Realistic Timing on a California Permit
District review times are the biggest variable in any new permit project. In Southern California, six to nine months from submission to ATC is the working assumption. BAAQMD varies by source type and complexity. SJVAPCD and Sacramento fall somewhere in between depending on workload.
That timeline matters most when a client has a specific install date or a corporate deadline. The honest version of the conversation is the one we have with every facility under deadline pressure:
Permits obtained by a hard deadline are usually not realistic if the deadline is sooner than six months out.
Permits submitted by a hard deadline are usually achievable if the data is available.
A permitting plan or roadmap by a hard deadline is almost always achievable.
Setting that expectation early is how scope and the district timeline stay aligned.
When the Application Gets More Involved
A few situations push a routine application into deeper territory:
- Older equipment without spec sheets. We document engineering assumptions and include them transparently in the packet so the district can review the basis for each emission factor.
- Proximity to a school. Some districts require public notification when a new source within a defined distance from a school is reviewed. The trigger is uncommon, the work is involved.
- Air dispersion modeling. Required in a small subset of cases (often where source distance, height, or pollutant load triggers it). Specialized and time-consuming when required.
- Equipment changes after the PTO is issued. A new piece of equipment, a process change, or a throughput increase usually requires a permit modification, which is its own application. See keeping your air permits current for how those get handled on an ongoing basis.
- Equipment running before the permit was issued. If a source has been operating without an ATC or PTO, the path back to compliance starts the same way as a new application, with additional documentation for the district. See operating without an air permit for what that looks like.
Working With CDMS on a Permit Application
Our consultants come to the facility for the site visit. The data collection, the forms, the emissions calculations, and the back-and-forth with the district engineer are handled from there. Where multiple permits are needed at one facility, we combine the work into a single proposal rather than charging per source. We do not bill for a permit application if the applicability review shows none is required.
Budgeting for the application? What affects the cost of an air quality permit in California →
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.
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