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 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)

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.

The most recently adopted ozone plan was prepared for the 1997 federal ozone standard.

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

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.