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Planning & CEQA

NCUAQMD Criteria Pollutant Attainment Status

The North Coast Air Basin is comprised of three air districts, the North Coast Unified AQMD, the Mendocino County AQMD, and the Northern Sonoma County APCD. The North Coast AQMD includes Del Norte, Humboldt, and Trinity Counties; the Mendocino County AQMD consists of Mendocino County; and the Northern Sonoma County APCD comprises the northern portion of Sonoma County.

The District is listed as "attainment" or "unclassified" for all the federal and state ambient air quality standards with the exception of the state 24-hour particulate (PM10) standard in Humboldt County only. The District has not exceeded the federal annual standard for particulate matter during the last five year period. Primary sources of particulate matter in the Eureka area are on-road vehicles (engine exhaust and dust from paved and unpaved roads), open burning of vegetation (both residential and commerical), residential wood stoves, and stationary industrial sources (factories).

In an effort to achieve the state air quality standard, an understanding of the causes of high PM10 levels is necessary. In 1995, the District provided a study to identify the major contributors of PM10, which is summarized in a NCUAQMD Paticulate Matter PM10 Attainment Plan draft report. This report should be used cautiously as it is not a document that is required in order for the District to come into attainment for the state standard, however, the District is planning to update the document.

Transportation, Land Use & CEQA

Cars and trucks and other vehicles are considered a source of particulate matter within the North Coast Unified Air Quality Management District (District). Fugitive emissions as a result of vehicular traffic on unpaved roadways is the largest source of particulate matter emissions within the District. Its control and mitigation plays a key role in the District's attainment strategy. Land use decisions often involve transporation.

Land use decisions are the general name for how a community uses its land, and land use decisions can affect air quality. Air pollution may result from a specific project, such as the construction of a new business that will emit air pollution, or may be related to the growth and transporation patterns of many new projects over a long period of time.

In order to provide consistency to lead agencies, project proponents, and the general public throughout the state, the California Air Pollution Control Officers Association (CAPCOA) prepared a guidance document, entitled "Health Risk Assessments for Proposed Land Use Project", to assist lead agencies with the requirements of the California Environmental Quality Act (CEQA) when projects may involve exposure to toxic air contaminants. This document focuses on the acute, chronic, and cancer impacts of sources that may undergo CEQA review. It also outlines the recommended procedures to identify when a project should undergo further risk evaluation, how to conduct the health risk assessment (HRA), how to engage the public, what to do with the results from the HRA, and what mitigation measures may be appropriate for various land use projects.

Environmental Review Guidelines

The California Environmental Quality Act (CEQA) is the state law that requires state and local agencies to identify the significant environmental impacts of projects and to avoid or mitigate those impacts, if feasible. Most proposals for physical development in California are subject to the provisions of CEQA, as are many governmental decisions which do not immediately result in physical development (such as the adoption of a general or community plan). Every development project which requires a discretionary governmental approval will require at least some environmental review pursuant to CEQA, unless an exemption applies.

The District's Planning Division staff participate in the preparation and review of environmental documents prepared by Humboldt County, Del Norte County, Trinity County, local cities, and other public agencies to determine potential adverse air quality impacts from projects, and identify measures to mitigate those impacts. The District is typically not the lead agency for projects, given the fact that other state, county, or city government agencies are usually considered the lead for most projects. When applicable, the District follows environmental review procedures and guidelines as outlined in the NCUAQMD Rules & Regulations, Appendix A, Procedures for Environmental Impact Review.

In determining whether a project has significant air quality impacts on the environment, planners typically apply their local air district's thresholds of significance to projects in the review process. However, the District has not formally adopted significance thresholds, but rather utilizes the Best Available Control Technology (BACT) emission rates for stationary sources as defined and listed in the NCUAQMD Rule and Regulations, Rule 110 - New Source Review (NSR) And Prevention of Significant Deterioration (PSD), Section 5.1 - BACT (pages 8-9). The District does not currently have any thresholds for toxics, but recommends the use of the latest version of the CAPCOA's "Health Risk Assessments for Proposed Land Use Project" as mentioned above, to evaluate and reduce air pollution impacts from new development.

The District strongly encourages planners, project applicants, and/or consultants, to contact the District's Permits & Planning Division to discuss projects and their impacts. District staff can be contacted at (707) 443-3093 or

Greenhouse Gases (GHGs) & Climate Change

Greenhouse Gases (GHGs) and Climate Change are a constantly evolving policy, especially in light of the passage of the Global Warming Solutions Act of 2006 (AB-32). As the California Air Resources Board and other state agencies and offices develop policies and regulations to address GHG emissions, the interface between the CEQA and these other programs may change.

As a result of revisions to the CEQA Guidelines that became effective in March 2010, lead agencies are obligated to determine whether a project's GHG emissions significantly affect the environment and to impose feasible mitigation to eliminate or substantially lessen any such significant effects.

In 2011, the NCUAQMD adopted Rule 111 (Federal Permitting Requirements for Sources of Greenhouse Gases) into the District rules, to establish a threshold above which New Source Review (NSR) and federal Title V permitting applies, and to establish federally enforceable limits on potential to emit greenhouse gases for stationary sources. These are considered requirements for stationary sources and should not be used as a threshold of significance for stationary source projects.

The District strongly encourages planners, project applicants, and/or consultants, to contact the District's Permits & Planning Division to discuss any questions related to GHG project impacts. Staff can be contacted at (707) 443-3093 or

The California Air Pollution Control Officers Association (CAPCOA) has also released a resource guide in January 2008, entitled "CEQA & Climate Change" to address GHG emissions from projects subject to the CEQA. This resource guide was prepared to support local governments as they develop their programs and policies around climate change issues. It is not a guidance document, and is not intended to dictate or direct how any agency chooses to address GHG emissions. Rather, it is intended to provide a common platform of information about key elements of CEQA as they pertain to GHG, including an analysis of different approaches to setting significance thresholds. The resource guide also contains an organized review of available tools and models for evaluating GHG emissions, and an overview of strategies for mitigating potentially significant GHG emissions from projects.

CAPCOA has also prepared a report entitled "Quantifying Greenhouse Gas Mitigation Measures". It is primarily focused on the quantification of project-level mitigation of greenhouse gas emissions associated with land use, transportation, energy use, and other related project areas. The report provides a discussion of background information on programs and other circumstances in which quantification of greenhouse gas emissions is important. This includes voluntary emission reduction efforts, project-level emission reduction efforts, reductions for regulatory compliance, and reductions for some form of credit. The information provided covers basic terms and concepts and does not endorse or provide guidance on any policy position.

AQ Models and Meteorological Data

Models are commonly used to calculate and predict project air emissions. The District requires that all CEQA, NEPA and other modeling use the most recent ARB approved modeling protocol or alternatives as approved by the District's Air Pollution Control Officer. District historical meteorological data files are also available for air dispersion or land use project modeling.

Historically URBEMIS was widely used to calculate project air emissions, however, a new air emissions model, the California Emissions Estimator Model (CalEEMod) is now being used. This model calculates both criteria pollutant and greenhouse gas emissions from projects.

The District strongly encourages planners, project applicants, and/or consultants, to contact the District's Permits & Planning Division to discuss any questions. District staff can be contacted at (707) 443-3093 or