Protecting Public Health and the Environment.

Tier II Air Quality Operating Permit

Who Qualifies for a Tier II Permit?

DEQ may require certain sources of air pollution to obtain Tier II permits. For example, DEQ might take this action as part of a state implementation plan designed to prevent further deterioration of air quality and to bring an area of the state back into compliance with the National Ambient Air Quality Standards (NAAQS). Tier II permits also may be issued to authorize an alternative emission limit for a particular emissions unit or units within a facility.

Synthetic Minor

Certain facilities that emit air pollution in Idaho may choose to obtain a Tier II instead of a Tier I permit. The fees for Tier II permits are lower and the reporting requirements less complex than those required for Tier I operating permits. To qualify for Tier II status, a facility would agree to limit production and/or hours of operation, thus lowering its potential to emit pollutants below Tier I permit thresholds. This type of Tier II permit is also known as a synthetic minor source permit.

Procedures and requirements for Tier II operating permits are found in the Rules for the Control of Air Pollution in Idaho (IDAPA–410).


Air modeling is required for certain permitting actions—including Tier II operating permits—to demonstrate that all applicable ambient air quality standards will be met if a proposed construction or facility modification is completed or that an existing facility is complying with the standards.

A DEQ guidance document has been developed to help air permit applicants understand DEQ’s expectations for ambient air impact analysis and prevent unnecessary delays in the permit process. The guideline describes in detail when modeling is required; explains applicable standards, methodology and analysis; and provides checklists and templates for conducting modeling and reporting modeling results.

Permit Application Process

Read these documents first to gain an understanding of the air quality permitting process:

Application Forms and Checklist

PTC application forms and checklists are provided for sources requiring this permit. The first step to submitting a successful air quality permit application is to read, Air Quality Permits: Applicant and DEQ Responsibilities. This document provides applicants with a basic understanding of DEQ's air quality permitting process, describes applicant responsibilities, and explains how DEQ will interact with applicants throughout the permitting process. Applicants are encouraged to contact the Air Quality Division to discuss permit application requirements early in the application process.

Applications submitted to DEQ for an air quality permit must be made on forms developed by DEQ. If you have questions about which form to use or about the application forms in general, call the permit hotline at 1-877-5PERMIT (1-877-573-7648).


No application fee is required for a Tier II permit application. A processing fee is assessed on the basis of emissions. DEQ calculates and assesses the fees according to the following schedule (fugitive emissions are excluded):

Tier II Permit Fee Fee Payment
General Permit1 $500 Must be paid in full within 45 days of receipt of DEQ assessment. Interest accrues if unpaid after 45 days.
Emissions < 1 ton per year $1,250
Emissions = 1-10 tons per year $2,500
Emissions = 10-100 tons per year $5,000
Emissions > 100 tons per year
Synthetic minor sources with emissions below major source threshold $10,000

1 General permit facilities include portable concrete batch plants, hot mix asphalt plants, and rock crushing plants.

How to Send Payment

Pay by check

Make check payable to the Idaho Department of Environmental Quality, and send completed application and check to the following:

Idaho Department of Environmental Quality
Attn: Fiscal Office - Air Quality Program
1410 N. Hilton
Boise, ID 83706

Pay by credit card/E-check

Link to Access Idaho website at
(Note: Convenience fee of 3% applies to credit card payments, $5 to E-check payments.)

Pay by bank wire transfer

Contact Lisa Pierce, DEQ Fiscal Office
(208) 373-0213

Fee Exceptions

So long as DEQ determines no other review or analysis is required, the Tier II operating permit processing fee is not required when the following applies:

  • A PTC that was issued within the last 5 years is rolled into a Tier II operating permit, or
  • A change to a Tier II permit is requested due to a typographical error, or
  • A change in the name or ownership of the holder of a Tier II operating permit is requested, or
  • A synthetic minor permit is issued and DEQ’s processing costs can be charged against the permittee’s Tier I fees.

Note: This is a summary of Tier II operating permit requirements and is not intended to be all-inclusive. Detailed requirements are outlined in the Rules for the Control of Air Pollution in Idaho.

Staff Contacts

Air Quality Permitting Hotline
1-877-5PERMIT (1-877-573-7648)
Call to set up a meeting or ask air quality permitting questions.

Air Quality Permit Supervisor
Darrin Pampaian
DEQ State Office
Air Quality Division
1410 N. Hilton
Boise, ID 83706
(208) 373-0587

Related Pages

Air Quality Permitting Forms and Checklists

Air Quality Dispersion Modeling

Small Business Environmental Solutions