Air operating permit for large sources of air pollution

Commercial and industrial businesses that emit large amounts of air pollution must get an air operating permit. An air operating permit is a master document that lists all of the air pollution requirements that apply to a business or industry. Ecology and other clean air agencies in Washington issue these permits.

Apply for an air operating permit

A business must turn in an air operating permit application 12 months before the business has the potential to emit:

  • More than 100 tons per year of any air pollutant.
  • More than 10 tons per year of any hazardous air pollutant.
  • More than 25 tons per year of a combination of hazardous air pollutants.

Even if a business emits less than these amounts, EPA may decide that it still needs an air operating permit. The federal rules that might apply include:

An air operating permit is valid for 5 years. A business must apply for renewal 6–18 months before the current permit expires.

Agencies that issue air operating permits

Agencies that issue air operating permits include:

Permit Register

Twice a month, we publish a Permit Register that lists milestones for air operating permits.

Review a draft air operating permit

Check for a public comment period and review a draft air operating permit:

Budget and fees

Workload analysis and budget report

Every two years, we prepare a workload model and a budget projection that evaluates the cost of reviewing, tracking, and overseeing air operating permits. After the public comment period, we finalize the workload analysis and budget.

Annual report

At the end of each fiscal year (July 1 – June 30), we prepare an annual report summarizing air operating permit program work and fees.

Fee schedule

We publish the current fiscal year’s fee schedule every year by October 31. If our costs were less than expected in the previous fiscal year, businesses are given a rebate toward their next year's fee.


Ecology and outside agencies regularly audit the air operating permit program.

  • Fiscal audit — Every two years, the Washington State Auditor’s Office conducts a fiscal audit of Ecology’s and each local clean air agency’s air operating permit program.
  • Performance audit — Every three years, Ecology and local clean air agencies conduct a routine overview performance audit.
  • EPA audits — Periodically, EPA also reviews the air operating permit program (EPA calls this Title V) and enforcement program.