Regulation under the Clean Air Act

The Clean Air Act is the primary federal law governing air pollution in the United States, passed first 1970. It gives the EPA authority to set limits on harmful pollutants, including particulate matter like coal dust, and to enforce these standards nationwide. Because they are harmful to our health, airborne particles are regulated as part of the Clean Air Act.

National Ambient Air Quality Standards

The U.S. Environmental Protection Agency (EPA) controls PM_2.5 and PM₁₀ as two of six criteria pollutants that must meet concentration thresholds known as the National Ambient Air Quality Standards (NAAQS), often pronounced as "the nacks". Exceeding these thresholds can trigger regulatory action, including stricter permitting requirements and enforcement measures.

NAAQS are divided into two categories:

• Primary standards, which protect human health, including sensitive populations such as children, the elderly, and individuals with respiratory conditions.
• Secondary standards, which safeguard public welfare, including protection against decreased visibility, damage to animals, crops, vegetation, and buildings.

Particulate Matter under NAAQS

The PM₁₀ NAAQS is a 24-hour average mass concentration of 150 μg/m³, not to be exceeded more than three times over three years. There are two PM_2.5 NAAQS: a 24-hour average mass concentration of 35 μg/m³ and a recently revised annual average mass concentration of 9 μg/m³. The NAAQS are set to protect public health, including the health of more sensitive individuals such those with asthma as well as children and elders. That said, there is no known safe level of exposure to PM_2.5, with documented health impacts below the NAAQS.

Monitoring and Compliance

Compliance with the Clean Air Act is determined through a combination of air quality monitoring, emissions reporting, and regulatory inspections.

• Monitoring: To determine NAAQS compliance, PM_2.5 and PM₁₀ must be measured using designated regulatory air monitors by an agency with the authority to do so, which in Virginia is the Department of Environmental Quality (VA DEQ).

• Permitting and Reporting: Facilities must obtain air permits that set specific emissions limits and require regular reporting of emissions data.

• Inspections and Enforcement: Agencies like the EPA or state departments (e.g., Virginia DEQ) conduct inspections and reviews. Violations can result in penalties or mandatory corrective actions.

NAAQS Compliance

Air quality is continuously monitored through a network of state and federal stations. If an area exceeds the standards, it may be designated as a “nonattainment area.” This designation triggers a series of regulatory steps aimed at reducing pollution, including:

• Emissions reduction plans
• Industry-specific control measures
• Public health advisories

Coal handling facilities and mining operations are often required to implement dust control technologies such as water sprays, windbreaks, and enclosures to minimize their contribution to PM levels.