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Permit Assistance: Air Quality

Environmental Permitting Overview

Construction and operating permits for air emissions may be required for many operations. Minor source Tier I, major source Tier II and Prevention of Significant Deterioration (PSD) Tier III requirements are found in DEQ rules at 252:4-7

  • Permit Exempt – A facility would not need an air permit if the Potential to Emit (PTE) is below major source levels (100 tons/year of any air pollutant subject to regulation and 10 TPY of any individual hazardous air pollutant and 25 TPY of all HAPs combined), actual emissions of each air pollutant subject to regulation are below 40 TPY, and the facility is not subject to any emission standard, equipment standard, or work practice standard, under New Source Performance Standard (NSPS) or National Emission Standard for Hazardous Air Pollutants (NESHAP).

  • Minor Source Permit – A minor source permit is needed if a facility does not qualify as Permit Exempt. Minor source permits are processed as Tier I permits with no public review. These permits are typically issued in 1-4 months but can be processed in as little as 2 weeks depending upon the need of the facility and the quality of the application.

  • Major Source Permit – A major source permit is required if the facility does not qualify under the lower categories. Major source permits are processed as Tier II permits and require 30-day public review of the draft permit and 45-day EPA review of the proposed permit. These are typically issued in 6-9 months but timelines vary depending on the company need, facility complexity and application quality.

  • PSD-Major Sources – PSD-major sources are large major sources with a regulated new Source Review pollutant above 250 TPY (this level can be 100TPY if it is a designated source type as classified by EPA). PSD-major source construction permits are processed as Tier III permits and require 30-day public review of the draft, 45-day EPA and 20-day public review of the proposed permit. These permits are typically issued in 9-12 months.

Certain limited construction activities are allowable prior to issuance of a Prevention of Significant Deterioration (PSD) permit in air. The following table identifies both allowed and prohibited activities.

Prior to Issuance of a PSD Permit
Allowable Activities Prohibited Activities (costly, significantly alter the site, or permanent in nature)
Planning Installation of building supports, retaining walls, and foundations
Ordering of equipment and materials Paving
Site-clearing Laying of underground pipe work
Grading Construction of permanent storage structures
Installing forms and rebar Pouring concrete
On-site storage of equipment and materials Excavating (includes blasting, removing rock and soil, and backfilling)
Construction on something that is not necessary for the PSD emissions unit to operate in accordance with its original intent Construction of any emissions unit that is an integral part of the new PSD source or modification, i.e., the new source or modification would not serve in accordance with its original intent except for inclusion of the emissions unit
Anything allowed for PSD permits, plus any construction that is not directly related to actually building the emissions unit Construction of the emissions unit such that the unit could be made operational

The full air permitting rules may be found at