Regional Haze

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With amendments to the Federal Clean Air Act in 1977, Congress declared a national goal to remedy visibility impairment at selected national parks and wilderness areas of the United States, known as Class 1 Areas. California has 29 Class 1 Areas managed by either the National Parks Service or the U.S. Forest Service.

In 1999, U.S. Environmental Protection Agency (U.S. EPA) promulgated the Regional Haze Rule. The Regional Haze Rule established requirements for states to develop State Implementation Plans (SIP) for regional haze. These SIPs are required to include long-term strategies and interim goals to demonstrate progress towards reducing visibility impairment in Class 1 areas affected by human-caused emissions of air pollution. 

Five Regional Planning Organizations (RPO) assist in the coordination of regional haze-related activities. The RPO that California belongs to is called the Western Regional Air Partnership (WRAP). WRAP oversees analyses of monitoring data and preparation of technical tools for regional haze planning efforts in the western states. 

Second Regional Haze Plan

California's second Regional Haze Plan describes progress made in California's Class 1 areas towards the national goal and details the long-term strategy to meet interim visibility goals set for 2028. 

The Board adopted California's second Regional Haze Plan at a public meeting held on June 23-24, 2022; it was submitted to U.S. EPA on August 9, 2022.

California's second regional haze progress report was embedded in the Regional Haze Plan submitted to U.S. EPA on August 9, 2022. A technical supplement to the progress report was submitted to U.S. EPA on August 23, 2023. 

Prior to releasing the draft Regional Haze Plan for public review, CARB provided federal land managers with the opportunity to review the plan. Comments provided by the federal land managers are included in Appendix I. Along with a comment letter, staff from the National Park Service (NPS) provided two data calculation files. These data files are available below for download.

NPS staff suggested that CARB make available device level emissions data for certain stationary sources considered. For reference, a data file with device level emissions data for stationary sources brought forward to the third screening step (discussed in Appendix G) is available below for download.  

As part of the Regional Haze Plan development process, CARB has hosted two public workshops. 

First Workshop

The first workshop was held on September 17, 2020. The agenda and presentation materials from this workshop are available below for download. 

Second Workshop

A second workshop was held on March 4, 2022. The workshop notice, workshop materials, and staff presentation are available below for download. A recording of the workshop is available through the link below. 

2014 Progress Report

The 2014 Progress Report assessed visibility improvements since 2004 and demonstrated California is on course to meet visibility goals for 2018.

U.S. EPA approved the 2014 Progress Report, effective May 1, 2015.  

After Board approval of the 2014 Progress Report at a public hearing on May 22, 2014, it was submitted to U.S. EPA on June 16, 2014.

First Regional Haze Plan

California's first Regional Haze Plan demonstrated reasonable progress in reducing haze by 2018, the first benchmark year on the path to improved visibility.

U.S. EPA approved California's Regional Haze Plan in the Federal Register on June 14, 2011.

The Board approved California's Regional Haze Plan at a public hearing on January 22, 2009; it was submitted to U.S. EPA on March 16, 2009.

Workshop

On December 15, 2008, CARB held a webcast workshop in Sacramento. The agenda and presentation materials are available below for download.