Protecting American Manufacturing/Examining EPA's Proposed PM2.5 Rule: U.S. House of Representatives Energy & Commerce Committee Hearing

The Environment, Manufacturing, and Critical Materials Subcommittee of the United States House of Representatives Energy & Commerce Committee held a September 19th hearing titled:

Protecting American Manufacturing: Examining EPA’s Proposed PM2.5 Rule (“Hearing”)

The stated purpose of the Hearing was to examine issues surrounding the United States Environmental Protection Agency’s (“EPA”)reconsideration of the Clean Air Act National Ambient Air Quality Standard (“NAAQS”) for fine particulate matter (“PM2.5”). The focus included potential implementation challenges and impacts on United States manufacturing and economic development.

Particulate matter is a generic term for a broad class of chemically and physically diverse substances that exist as discrete particles (liquid droplets or solids) over a wide range of sizes. It is composed of two major components.

Primary particulates or soot are emitted directly into the atmosphere. Secondary particulates can also be formed through a secondary process. They might be formed from condensation of high-temperature vapor from vapors generated as a result of chemical reactions involving gas-based precursors.

Larger particulates (PM10) are generally the result of mechanical, evaporative, and suspension processes. Particulates designated PM2.5 typically consist of sulfates, nitrates, elemental carbon, organic carbon, compounds or metals. Because of their small size, these particulates can remain in the air for significant periods of time.

Sections 108 and 109 of the Clean Air Act require EPA to identify air pollutants utilizing certain criteria and set NAAQS for each. Particulates are one of the six air pollutants currently designated as criteria air pollutants and subject to NAAQS. Section 109 requires that EPA promulgate primary NAAQS for the pollutants identified under Section 108.

Section 109(b)(1) defines a primary standard as one “the attainment and maintenance of which, in the judgment of the Administrator, based on the criteria and allowing an adequate margin of safety, are requisite to protect the public health.” The margin of safety requirement addresses the uncertainties associated with the inconclusive scientific and technical information available, as well as to provide a reasonable degree of protection against the adverse effects that may not have been discovered.

Section 109(d)(1) of the Clean Air Act mandates a periodic review of each NAAQS. Depending on the results of the review, EPA must determine whether the existing air quality criteria and NAAQS must be revised. EPA’s review of the PM2.5 is an example of this review process.

EPA announced in 2022 that it was reconsidering the Trump Administration’s prior decision to retain the PM2.5 NAAQS. EPA subsequently issued a proposed rule soliciting comments on strengthening the annual PM2.5 NAAQS. This was stated to be driven by the federal agency’s belief that it reflects the latest health data and scientific evidence. Further, the proposed rule considered updating monitoring requirements.

Note that the states are primarily responsible for ensuring attainment and maintenance of a NAAQS once the EPA has established or revised them. Each state is therefore required to formulate, subject to EPA approval, an implementation plan (i.e., SIP) designed to achieve each NAAQS.

The SIPs will contain the measures and actions the state proposes to undertake to attain each NAAQS. These measures or actions must be enforceable through state regulations and typically include emission limits applicable to certain types of stationary sources.

The September 19th Hearing was scheduled to address at a minimum the following issues:

• Impacts of the proposed PM2.5 standards on industrial manufacturing and economic expansion
• Timing, monitoring, permitting, and emissions-source challenges relating to implementing the proposed PM2.5 standards
• Clean Air Act requirements to review the welfare and economic impacts and related challenges concerning implementation of the proposed NAAQS standards
• Exception events process under the NAAQS program

Links to the witnesses’ testimony can be found below:

The staff memorandum prepared by Subcommittee staff can be downloaded here.