Cumulative impacts are defined by US Environmental Protection Agency (EPA) as the combined exposures to both chemical and nonchemical stressors and their effects on human health. The concepts are not new, dating back to the 1970s. The Cumulative Impact Assessment (CIA) is the process of evaluating the data required that represents these cumulative impacts. Within Massachusetts and several other states including California, Minnesota and New Jersey, this new focus on CIA is clearly linked to Environmental Justice (EJ) concerns. Additional analyses to satisfy requirements that go beyond what is currently required under the Massachusetts Environmental Policy Act (MEPA) must be conducted (further identified below).

These new requirements apply to both new and existing sources. The designated area that needs to be evaluated will depend on whether the source is a non-major or a major source. Existing sources will be required to conduct a CIA if they are applying for a new CPA and will be increasing emissions by one ton or more per year facility-wide, with exceptions.

  1. Start early. Based on these new air permitting requirements, in most cases more time will be needed to complete permit applications. This is due to added time needed for public notice and community outreach and an extended public comment period during the permit review. As such, we strongly advise starting this phase of the process early on.
  2. Additional air modeling and risk assessment. In most cases air dispersion modeling will be needed for both criteria and air toxics, and greater level of effort in analyzing resulting data, given expanded requirements.
  3. Vehicle traffic and other major sources MassDEP may require the consideration of impacts from other major sources, including transportation-related impacts.
  4. Mitigation. Greater consideration of mitigation measures may be needed based on CIA results.

Similarities between CIA and MEPA requirements include the public outreach, assessment of community health and environmental burdens and evaluation of impacts to EJ communities. The major differences for a CIA include requirements to complete air dispersion modeling and a risk assessment for air toxic risks.

Epsilon has completed comprehensive EJ analyses including public outreach, assessment of environmental and health burdens, and evaluation of emissions impact on EJ populations, often conducting air dispersion modeling to show that a facility will not adversely impact EJ communities. These evaluations have been expanded as part of the CIA requirements for any facilities submitting a CPA that are in or near EJ communities.

Mass.gov regulations, guidance and tools for Cumulative Impact Analysis in Air Quality Permitting

Massachusetts Leads Nation with New Cumulative Impact Analyses Requirements for Air Quality Permits Near EJ Populations (April 2024)

Epsilon guides our clients through the rapidly changing landscape of air quality standards and regulatory requirements, obtaining approvals for new development and helping existing facilities ensure compliance. We work across disciplines with developers, engineers, and operations staff to provide seamless environmental support.

Epsilon prepares air permit applications (including PSD/NSR), environmental impact documents, environmental justice evaluations, siting and licensing applications, due diligence reviews, risk management plans, public presentations, environmental management systems, and responses to agency enforcement. Our Certified Consulting Meteorologists and Professional Engineers have provided expert testimony for dozens of projects.