Clean Air Act Regulations

The Clean Air Act authorizes US EPA to set limits on the volume of certain pollutants, known as “criteria pollutants”, that is acceptable in the ambient air. The six criteria pollutants are: carbon monoxide, lead, nitrogen oxides, sulfur dioxide, particulate matter, and ozone. The current EPA NAAQS can be found at 40 CFR 50.

For each criteria pollutant regulated by the Clean Air Act NAAQS limits, EPA designates geographic regions of the US—called air quality control regions (AQCRs)—as being “in attainment” or “in non-attainment.”

Simply put, if a region is in attainment, it means the concentration of the pollutant in the ambient is below EPA’s limit. If a region is designated as in non-attainment, it means the concentration of that pollutant is above EPA’s threshold. When a source is located in a non-attainment region, it often means more stringent requirements for controlling air pollution. Check your region! The physical boundaries and current air quality designations for all AQCRs in the US can be found at 40 CFR 81.

Identifying a major source relevant to New Source Review depends on whether the new or modified source will be located in an attainment or non-attainment air quality control region. In non-attainment regions, the definition of “major source” is broader, encompassing more sources than would be covered in an attainment region.

New Source Performance Standards requirements are technology-based standards developed by US EPA to control air pollution from affected facilities. The current New Source Performance Standards can be found at 40 CFR Part 60. EPA is authorized to set these standards under Section 111 of the Clean Air Act.

In this context, “affected facilities” means any apparatus identified in 40 CFR 60 that can emit one or more of the six criteria pollutants. Under the NSPS, sites must monitor emission and/or conduct performance tests to demonstrate compliance. These rules apply to new, modified, or reconstructed apparatuses.

Like New Source Performance Standards (NSPS), National Emissions Standards for Hazardous Air Pollutants (NESHAPS) limit how much pollution a given source can emit. However, instead of organizing the limits based on the criteria pollutants, EPA assigns NESHAPS based on a broader category: Hazardous Air Pollutants (HAPs). NESHAPs require specific technologies and controls be applied to specific equipment to prevent the pollution emitted from that equipment from exceeding EPA’s thresholds. The NESHAPs can be found at 40 CFR 61 and 63.

Since 2012, certain facilities that emit greenhouse gases must submit a mandatory annual report under the Clean Air Act. The thresholds for greenhouse gas reporting are assigned based on industry (see 40 CFR 98). Facilities in certain industries—like electricity generation, petrochemical production, and municipal landfills—must report every year, regardless of their greenhouse gas emission levels. Other sources must report if they exceed a specified amount of carbon dioxide (CO2) equivalent emissions. As of December 2013, all Clean Air Act greenhouse gas reporting must be done through EPA’s web portal, the Electronic Greenhouse Gas Reporting Tool, or e-GGRT.

Before constructing a new major source of air pollution or making modifications to an existing major source, owners and/or operators must go through New Source Review (NSR). New Source Review is a pre-construction review program that determines if the proposed emissions control technology installed during construction will be adequate to achieve Clean Air Act NAAQS goals for the region.

Ozone-depleting substances (ODS) are chemicals that have a deleterious effect on the stratospheric ozone layer. Since the United States became a signatory to the Montreal Protocol in 1987, EPA has regulated the production, import, consumption, use, destruction, and recycling of these chemicals. The ultimate goal is the complete phase-out of production of ODS in accordance with the Protocol’s time lines. Under the Clean Air Act, ODS are divided into two designations: Class I and Class II, listed at 40 CFR 82, Appendices A and B. Production of Class I ODS was phased out in January 2000, while Class II ODS are on schedule to be phased out by January 2030.

US EPA’s Clean Air Act Risk Management Plan (RMP) requirements, found at 40 CFR 68, apply to stationary sources that have certain flammable or toxic chemicals, in certain amounts, at any time in a single process. The plans are intended to help reduce the risks of a catastrophic release and minimize the consequences if and when an incident occurs.