Air Permitting in Industrial Site Selection

When embarking on a site selection project, companies often focus on the most apparent factors such as the availability of qualified labor, real estate, and economic incentives.  However, one of the most often overlooked elements, air permitting, can quickly become a project’s biggest hurdle. Site Selection Group, a full-service location advisory, economic incentives, and real estate service firm, understands the importance of proactively addressing air permitting early in the process to avoid costly delays and project setbacks.

Air Permitting 101

Air permitting generally describes the regulatory process by which the U.S. Environmental Protection Agency (EPA) and state-level agencies limit the amount of pollutants an industrial facility can release (or emit), ensuring that new or expanding facilities do not adversely affect public health or the environment.  While the EPA sets national standards, each state implements and enforces its own permitting programs, meaning a permit’s complexity, cost, and timeline can vary dramatically across candidate sites in a site selection search.  The overall process is governed by the Clean Air Act, a federal law that requires industrial facilities to secure air permits prior to constructing a new facility or expanding an existing one.

The EPA uses the following six air pollutants as indicators of air quality:

• Ozone (as Volatile Organic Compounds (VOC) and NOx)
• Particulate Matter (PM), PM less than 10 micrometers in diameter (PM10), and PM less than 2.5 micrometers in diameter (PM2.5)
• Carbon Monoxide (CO)
• Lead (Pb)
• Sulfur Dioxides (SO2)
• Nitrogen Oxides (NOx)

Beyond the common air pollutants, facilities may also be required to regulate Hazardous Air Pollutants (HAPs), a list of 187 specific substances, and Greenhouse Gases (GHGs), such as carbon dioxide. Major source thresholds for HAPs are typically 10 tons per year for a single HAP or 25 tons per year for a combination of HAPs.

For industrial site selection purposes, there are two primary permits to consider:

Minor Source

Air permits for facilities that will emit pollutants below an established regulatory threshold set by state and federal agencies.  While less complex, it still requires application and review processes to ensure compliance.  This category also includes "Permit by Rule" or "Permit by Right," which are simplified, streamlined processes for facilities that fit a specific set of pre-approved conditions, as well as Synthetic Minor Source permits, which allow a facility that would otherwise be classified as a major source to accept legally enforceable operational limits to cap its emissions below major source thresholds.

Major Source (or Title V)

Air permits for facilities that “has actual or potential emissions at or above the major source threshold for any 'air pollutant'.” The major source threshold for any air pollutant is 100 tons per year, and lower thresholds may apply in non-attainment areas for the pollutant that are in non-attainment.” (EPA, August 2025).  The process for a major source permit is far more rigorous, involving extensive data modeling, a longer public review period, and stricter ongoing monitoring and reporting requirements.

A critical distinction also exists between construction permits and operating permits. A construction permit gives a company permission to build or modify a facility with potential air emissions.  This is often referred to as a Prevention of Significant Deterioration (PSD) permit for new major sources in attainment areas.  However, once construction is finished, a separate operating permit, such as a Title V permit, is required to legally begin and continue operations.  This means that even after a site is prepared, the regulatory clock is still ticking, underscoring the need for a long-term, proactive approach to avoid project delays.

Understanding which type of permit a project will require is a critical step in the planning process, as it will impact the scope and timeline of construction start and operational launch, as well as have implications for ongoing operations and potential future expansions.

Air Permitting Implications for Industrial Site Selection

A site’s geographic location is one of the single most influential factors in the permitting process, specifically the location within an attainment vs. non-attainment area. According to the EPA, “If the air quality in a geographic area meets or is cleaner than the national standard, it is called an attainment area (designated 'attainment/unclassifiable'); areas that don't meet the national standard are called nonattainment areas.”  In layman’s terms, it is ideal to locate a facility within an attainment area, especially one that will require a major source permit.  Locating a major source project in a non-attainment area will introduce significant complexities and additional requirements, such as securing offsets for emissions.  It is important to note that an area can be in attainment for one pollutant but in non-attainment for another.  A non-attainment area is an immediate red flag that can make an otherwise ideal site a poor choice.

One of the biggest potential impacts of air permitting is on a project’s timeline.  Although timelines vary by state and locality, air permits can require a couple of months up to a year or longer, depending on various factors such as the type of permit required (minor vs. major source), site location, manufacturing processes, and procedural delays such as permits waiting to be processed. For projects that require a major source permit, it is not uncommon for this to be one of the longest lead time items in the Gannt Chart, and failing to plan properly can derail a project’s timeline and cause significant detriment to the return on investment.

Site Selection Group Can Proactively Address Air Permitting

Navigating the complexities of air permitting requires an intentional, strategic approach that should be initiated during the project planning stage.  Engaging experts early ensures that air permitting is lock-step in the process alongside other critical due diligence activities.  A qualified environmental consultant and an experienced site selection team can perform a preliminary air permit analysis upstream in the process.  This analysis involves understanding state-specific regulations, analyzing local air quality, and collaborating with regulators to model the proposed facility's specific emission profile.  Early engagement can quickly eliminate sites that would require a lengthy or complicated permitting process, saving significant time and resources.