USEPA proposes new standards for fine particulate matter

February 2023

Based on the latest health data and scientific evidence, USEPA has proposed strengthening federal air quality standards for one of the nation’s most harmful types of air pollution — fine particulate matter.

On January 27, 2023, the US Environmental Protection Agency (USEPA) published its proposal to strengthen a key national ambient air quality standard (NAAQS) for fine particle pollution, also known as PM2.5, to better protect public health.

The proposal lowers the primary annual PM2.5 standard from its current level of 12.0 μg/m3 to a value within the range of 9.0 to 10.0 μg/m3, reflecting the latest health data and scientific evidence.

In addition, USEPA has proposed to retain all other PM standards and to revise the air quality index (AQI) and monitoring network requirements. This long-awaited proposal also highlights USEPA’s growing focus on environmental justice, addressing disproportionately higher PM exposure to at-risk communities. 

If finalized, the impacts will be felt nationwide. 

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Implications of the proposal 

Due to the USEPA’s prioritization of environmental justice and influence from environmental advocacy groups and academics, it is likely that the final standard adopted by USEPA will be significantly more stringent than the current standard. This is expected to bring a new set of challenges to industry. 

Ramboll experts suggest considering the following primary implications:

  1. New or altered nonattainment area designations: Additional regions will be categorized as nonattainment, predominantly in western states as well as many urbanized areas throughout the US. To find the current and projected attainment status of your area under the new standards, review USEPA’s county map.
  2. Consequential rulemaking: There could be enhanced state PM and PM precursor (NOX, SO2, VOC and NH3) emission reduction measures and regulations in conjunction with finalized State Implementation Plans (SIPs).
  3. Newly triggered regulations: Facilities in newly designated nonattainment areas may become subject to nonattainment new source review (NNSR) for major sources or major modifications. NNSR requires the lowest achievable emissions rate, potential emissions offsets, and public involvement for major sources.
  4. Dispersion model demonstrations: Demonstrating NAAQS compliance through dispersion modeling will become more challenging under the revised annual PM2.5 standard. Projects undergoing Prevention of Significant Deterioration (PSD) permitting in attainment regions, or other minor projects which require dispersion modeling, may need to demonstrate additional decreases in PM emissions to demonstrate NAAQS compliance. In many areas of the US, annual background PM2.5 concentrations are already close to the proposed standards, and lowered NAAQS will make modeled compliance demonstrations significantly more difficult.
  5. Monitoring network changes: To enhance the protection of air quality in communities subject to disproportionate air pollution risk, USEPA proposes to modify PM2.5 monitoring network design criteria to include an environmental justice factor that accounts for the proximity of populations at increased risk of adverse health effects from PM2.5 exposures to sources of concern. Increased awareness of at-risk communities near sources of concern, such as ports, rail yards, airports, industrial areas or major roadways, may be needed.

USEPA_Timeline-graphic003R

 

Summary

The annual PM2.5 standard is expected to be approved at a lower level – but exactly how much lower is currently undecided. While the exact implications of this proposal will vary by state and region, additional PM and PM precursor emission reduction measures are expected, especially in areas that will not meet the proposed lower standard.

Ramboll will continue to monitor these upcoming regulatory developments and closely follow activity related to USEPA’s reconsideration of PM NAAQS.

How Ramboll can help

Ramboll’s air quality professionals apply cutting-edge science and methodologies to the development of tailored solutions to facility, local and regional air quality issues. Our experts provide support for permitting, ongoing compliance and defense of enforcement actions. We understand the applicable regulations, and, perhaps more importantly, the intent behind them. Our sophisticated understanding of the regulatory process enables us to partner with our clients to resolve their issues. Clients benefit from the credibility and trust that we have earned through many years of interactions with regulators.

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About the authors

Michael McCarthy

Air Quality Consultant

Michael is an air quality specialist with experience in CEQA analyses, dispersion modeling, health risk assessments, GHG analyses, mobile source evaluations, air permitting, and emissions inventories. He has worked closely with several regulatory agencies, including USEPA, UDEQ, IDEQ, CARB, and BAAQMD, and has experience with various emissions and modeling software tools, including AERMOD, CalEEMod, EMFAC and Python, and GIS software programs such as ArcGIS and AutoCAD.

Sim Deshpande

Senior Managing Consultant

Sim specializes in air permitting and compliance with specific experience managing complex air permitting projects – including PSD and/or NNSR – in the pulp and paper, oil and gas, chemical manufacturing and electrical power generation sectors. Sim's experience also includes assisting pulp and paper mills and coal/oil-fired power plants with four-factor analyses in support of the Regional Haze Rule second implementation period. In addition, Sim has conducted numerous control technology analyses in support of BACT, LAER and BART evaluations, and has managed several complex air dispersion modeling projects in support of permitting actions.

Megan Neiderhiser

PE, Principal

Megan specializes in air quality management with particular experience in air dispersion modeling, air permitting and compliance, human health risk assessment and NEPA evaluation. Her expertise also spans GHG management and sustainability planning. In her role directing projects for industrial and public entity clients, Megan has worked closely with several air agencies across the western US, and has extensive experience with several emissions and modeling software tools, including AEDT, AERMOD, CalEEMod and MOVES. She also has specialized experience in the airport sector and was elected the Air Quality Co-Chair of the Airports Council International – North America Environmental Affairs Committee Steering Group.