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.

The specific chemical substances subject to RMP requirements, and their corresponding volume thresholds, can be found in the four tables at 40 CFR 68.130.

• Tables 1 and 2 list the regulated “toxic” substances (based on the EPCRA extremely hazardous substance criteria).

• Tables 3 and 4 list the regulated “flammable” substances.

The Clean Air Act RMP requirements define a stationary source as a place or object from which pollutants are released and which does not move (e.g., power plants, gas stations, incinerators). A mobile source, on the other hand, typically refers to an automobile or other fuel-burning vehicle.

A single process, as defined in the RMP regulations, means the use, storage, manufacture, handling, or movement of a hazardous substance. If any of these activities require a chemical to pass through multiple interconnected vessels, all of the interconnected vessels are considered to be part of the same single process. In fact, even when separated vessels are used, the vessels may be considered part of the same single process under the RMP rules, if a release from one vessel could affect the operations of another. [40 CFR 68.3]

A Risk Management Plan must be certified by the operators of the stationary source, must be reviewed at least every 5 years, and must include descriptions of the following:

• The site, the covered process, and the covered substances,

• The process’ five-year accident history,

• The process’ hazard assessment,

• A worst-case release scenario, and

• The process’ prevention and emergency response programs.

When fossil fuels are burned, hazardous chemicals like sulfur dioxide and nitrogen oxides rise into the air, lowering the pH of the moisture in the atmosphere When these pollutants return to earth in the form of precipitation (rain, snow, fog), that’s called acid rain.

The Clean Air Act Amendments of 1990 authorized US EPA to take steps to control acid rain. Owners and operators of affected “units” must comply with the acid rain permit rules found at 40 CFR 72. A unit in this context means an individual combustion device—a boiler, furnace, combustion turbine, engine, etc. Power plants—the #1 target of EPA’s acid rain program—often house more than one affected unit per plant. A big part of EPA’s acid rain program is cap-and-trade, a system that allows facilities to transfer pollution rights to one another. Each allowance obtained through trade is an authorization from EPA to emit up to 1 ton of sulfur dioxide.