Planning for Ozone Standards

Ground-level ozone, best known as smog, is an air pollutant seen primarily in the summer and fall which can inhibit breathing and damage respiratory systems at higher concentrations. Breathing ozone is akin to giving your lungs a sunburn: the pollutant damages healthy cells and prolonged exposure can lead to serious health impacts.

Ozone levels in Yolo-Solano are in the healthy range on most days. However, ozone and its precursors don’t respect political boundaries, and emissions created within Yolo and Solano counties do affect neighboring communities, especially in the greater Sacramento region.

As such, the Yolo-Solano AQMD is included in the Sacramento Federal Non-attainment (SFNA) Area by the U.S. Environmental Protection Agency (EPA). Because emissions created here impact the air quality of neighboring jurisdictions, the  Yolo-Solano AQMD is responsible for helping the regional air districts meet health standards for ozone. This is accomplished through the cooperative planning efforts of the air districts within the region.

The Clean Air Act requires areas not meeting health standards to develop strategies to achieve those standards by federal deadlines. The air districts of the Sacramento region work together to develop these plans and update them as required.

Regional air quality plans contain inventories of current and projected emissions from all relevant sources as well as proposed control measures intended to reduce these emissions in order to achieve healthy air quality levels. These control measures typically come in the form of new rules or revisions to existing rules.  These rules define and enforce acceptable emission limits for stationary sources. (While cars and trucks produce the majority of ozone in our area, local air districts have no regulatory authority over them.  Mobile sources are regulated by the Air Resources Board)

Wildfires Mitigation Plan for SFNA

The Sacramento Federal Nonattainment Area for PM2.5 (SFNA-PM2.5), which includes Sacramento County, eastern portion of Yolo County, northwest portion of Solano County, and western portions of El Dorado and Placer Counties, has been identified by the United States Environmental Protection Agency (EPA) as an area that is required to develop a mitigation plan to minimize the public exposure from PM2.5  emissions generated during wildfire events. Air districts in the SFNA-PM2.5 have jointly prepared the draft Wildfire Mitigation Plan for the Sacramento Federal Nonattainment Area for PM2.5 (Plan) as required by Title 40, Code of Federal Regulations, Part 51.930 (40 CFR 51.930)

This draft Plan outlines the actions each air district will take to notify the public and minimize the air quality impacts when emissions from wildfires increase PM2.5 concentrations in the region to a level where they exceed or are expected to exceed the 24-hour PM2.5 national ambient air quality standard.

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Federal Ozone Attainment Plan

The U.S. EPA periodically reviews its air quality standards for regulated pollutants.  The EPA may also revise its standards when health studies indicate that a revision is necessary to protect the most sensitive segments of the population.  Each time a new standard is adopted by EPA, local air districts must prepare plans to show how the standard will be achieved by the appropriate deadline.

As a nonattainment area for the federal ozone standard, the Sacramento region is required to prepare various planning documents on an ongoing basis.  These documents include Milestone Reports and Reasonable Further Progress Plans.

The Federal Clean Air Act (CAA), Part D, Section 182(b)(2) requires ozone nonattainment areas to implement reasonably available control technology (RACT) for certain categories of sources.  The District’s RACT analysis was approved by the District’s Board of Directors on September 13, 2017.

Sacramento Regional 2008 NAAQS Attainment

The District’s Board of Directors held a Public Hearing on October 11, 2017 and adopted the Sacramento Regional 2008 National Ambient Air Quality Standard (NAAQS) 8-Hour Ozone Attainment and Reasonable Further Progress Plan (Plan).

The Plan geographically covers the Sacramento Federal Nonattainment Area (SFNA) which includes all of Sacramento and Yolo counties, and portions of Placer, El Dorado, Solano, and Sutter counties. Each air district in the SFNA held separate public hearings to adopt this Plan. The Plan documents how the region is meeting requirements under the Clean Air Act in demonstrating reasonable further progress and attainment of the 2008 NAAQS of 75 parts of ozone per billion.

State Triennial Plan

In July 2016, Yolo-Solano AQMD adopted its most recent Triennial Plan Update.

The Triennial Plan Update is a requirement of the California Clean Air Act of 1988.  According to the Act, each air district must adopt a plan for attaining and maintaining state ambient air quality standards for ozone.  The plan must be updated every three years.  The original District plan was adopted in 1992.  This most recent plan update covers the years 2012 -2014.  The document summarizes emission trends over this time period, forecasts future emissions, and reviews efforts made by the District to improve air quality.