Air Permitting Overview

The Clean Air Act (CAA) of 1970 and subsequent amendments of 1990 gave the federal government and states the power to regulate air emissions. The Environmental Protection Agency (EPA) sets an emission limit, or National Ambient Air Quality Standard (NAAQS), and each state has the power to craft a plan to meet that NAAQS. Each creates a State Implementation Plan (SIP) that tells the EPA how they plan to meet the federal emission standards. Each state also has the power to make a more stringent standard but they must, at a minimum, meet the NAAQS. 


A specific area is said to be in Attainment if they are able to meet that standard, and said to be in Non-Attainment if they cannot. If they cannot meet the standard, state government agencies will look to pass regulations that will help meet the standard. 


The standard major source threshold is 100 tpy of any contaminant and less in a non-attainment area for that specific contaminant. Per 40 CFR § 70.2, major sources with the potential to emit 100 tpy or more of volatile organic compounds or oxides of nitrogen are classified as “Marginal” or “Moderate,” 50 tpy or more in areas classified or treated as classified as “Serious,” 25 tpy or more in areas classified or treated as classified as “Severe,” and 10 tpy or more in areas classified or treated as classified as “Extreme”. 


One of the major results of the CAA was the creation of the Title V Air Permitting program. Under the Title V program, Title V of the 1990 CAAA, Major Sources would be required to meet various compliance requirements including monitoring, reporting, and testing. Certain Area Sources may also be required to obtain a Title V permit at the request of the Administrator. 

The EPA defines a Major and an Area source as:

  • "Major" sources are defined as sources that emit 10 tons per year of any of the listed toxic air pollutants, or 25 tons per year of a mixture of air toxics. These sources may release air toxics from equipment leaks, when materials are transferred from one location to another, or during discharge through emission stacks or vents.
  • "Area" sources consist of smaller-size facilities that release lesser quantities of toxic pollutants into the air. Area sources are defined as sources that emit less than 10 tons per year of a single air toxic, or less than 25 tons per year (tpy) of a combination of air toxics. Though emissions from individual area sources are often relatively small, collectively their emissions can be of concern - particularly where large numbers of sources are located in heavily populated areas.

[ Source: Last Updated 2/23/2016 ]

In most cases the trigger for a facility to fall under Title V will be if their annual NOx emissions exceed 25 tons per year due to the consumption of fossil fuels. 


This is on a potential to emit basis-all emission units onsite firing their dirtiest fuel at maximum load for 8760 hours per year.  The AP42 and EPA Webfire are used to obtain appropriate emission factors for each operating unit.


Contact us to discuss how we can tailor a compliance program to fit your facilities needs.

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Randy Thompson