Air Quality Permitting
DEQ is the state agency delegated by the federal government to issue air quality permits in Idaho. Permits are required by the federal Clean Air Act and set the conditions under which facilities that generate air pollution may operate. The purpose of permits is to ensure compliance with all state and federal air pollution control rules, which are designed to protect public health and the environment.
Applications submitted to DEQ for an air quality permit must be made on forms developed by DEQ. Application forms are available at Air Quality Permitting Forms and Checklists. 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).
Any business or industry (source) in Idaho that emits, or has the potential to emit, pollutants into the air is required to have an air pollution control permit from DEQ. Permits are issued when new sources begin operation and when existing sources modify their facilities.
Preapplication Process
DEQ is committed to issuing air quality permits in a timely manner and employs a staff of engineers devoted to this task. Facilities, too, play a key role in the timely development and issuance of air quality permits. Timeliness depends upon completeness of information—DEQ must have all necessary information before its engineer can determine an application complete and then begin to develop the permit. Learn more.
Types of Permits
DEQ's Air Quality Division issues several different types of permits based on the emissions from the facility and/or emitting source. Permits require sources to comply with all health- and technology-based standards established by EPA and the Rules for Control of Air Pollution in Idaho. If an applicant demonstrates compliance with all applicable federal and state air pollution laws and regulations, DEQ is required by law to issue an air permit.
The permit and accompanying statement of basis include detailed information on the type(s) of pollutants released, how much may be released, how the facility will comply with the air pollution control rules, and how the pollutants will be monitored. Violation of the permit provisions can result in enforcement action.
Four types of permits are issued: permit to construct (PTC), permit by rule (PBR), Tier I (Title V) operating permit, and Tier II operating permit.
Permit to Construct
An air quality PTC is required prior to construction or modification of stationary sources, such as buildings, structures, and other installations that emit, or may emit, pollutants into the air. A PTC is also required for certain portable equipment such as generators, crushing equipment, asphalt plants, and concrete batch plants. General PTC to construct may be available for some portable facilities. Learn more.
- General Permit to Construct for Automotive Coating Operations
- General Permit to Construct for Concrete Batch Plants
- Hot-Mix Asphalt Plants
- Permit to Construct Exemptions
Permit by Rule
A PBR is a streamlined registration process that enables qualified applicants to bypass the need to obtain a PTC or Tier II operating permit before beginning operation. Currently, the opportunity to obtain a PBR is available to nonmetallic mineral processing plants (portable rock crushing facilities) and certain dairies. In addition, under the crop residue burning program, growers must obtain approval from DEQ before burning by registering for a PBR at least 30 days in advance of a proposed burn date. PBRs for other industries are being considered. Learn more.
Tier I Air Quality Operating Permit
A Tier I operating permit (also known as a Title V operating permit) is required by the federal Clean Air Act for major sources. Major sources are sources that emit, or may emit, 100 or more tons of any regulated air pollutant per year, 10 or more tons per year of any one hazardous air pollutant (HAP), or 25 or more tons per year of any combination of hazardous air pollutants. Learn more.
Tier II Air Quality Operating Permit
Certain facilities that emit air pollution in Idaho may choose to limit production and/or hours of operation, thus lowering their potential to emit pollutants below Tier I permit thresholds and qualifying them for a Tier II operating permit. In other cases, DEQ may require certain sources of air pollution to obtain Tier II permits. The fees for Tier II permits are lower, and the reporting requirements less complex than those required for Tier I operating permits. Learn more.
Air Quality Permitting Forms and Checklists
Find helpful checklists and required forms for air quality permits here.
Air Quality Emission Inventory Requirements and Forms
Applicants for air quality permits must submit emission inventories based on the type of project being proposed and the type of permit required. Learn more.
Air Quality Dispersion Modeling
Air quality dispersion modeling is used to estimate concentrations of pollutants that new (or existing) emissions sources may emit. Idaho requires air modeling to demonstrate compliance with the National Ambient Air Quality Standards (NAAQS), toxic air pollutant (TAP) standards, and Prevention of Significant Deterioration (PSD) increments. Learn more.