Regional Haze


One of the most common forms of air pollution - haze - degrades visibility in many American cities and scenic areas. Haze is caused when sunlight encounters tiny pollution particles in the air, which reduce the clarity and color of what we see, particularly during humid conditions.

Where does haze-forming pollution come from?

Air pollutants come from a variety of natural and manmade sources. Natural sources can include windblown dust, and soot from wildfires. Manmade sources can include motor vehicles, electric utility and industrial fuel burning, and manufacturing operations. Particulate matter pollution is the major cause of reduced visibility (haze) in parts of the United States, including many of our national parks.

Some haze-causing particles are directly emitted to the air. Others are formed when gases emitted to the air form particles as they are carried many miles from their source.

What is being done to reduce regional haze impacts?

The Clean Air Act of 1990 (Title I, Sections 169A and 169B) declared it a national goal to prevent any future, and to remedy any existing, impairment of visibility in 156 mandatory Class I Federal areas, the impairment of which results from manmade air pollution. In 1999, the U.S. Environmental Protection Agency (EPA) issued regulations for the protection of visibility in Class I National Parks and Wilderness Areas. Revisions to the regional haze rules were promulgated on July 6, 2005 and October 13, 2006. These regulations require states to establish goals for improving visibility by developing long-term strategies for reducing emissions of air pollutants that cause visibility impairment. The overall goal of the regional haze regulations is to achieve natural background visibility conditions in all Class I areas by the year 2064.

EPA and other agencies have been monitoring visibility in national parks and wilderness areas since 1988. The Regional Haze Rule requires the states, in coordination with the EPA, the National Park Service, U.S. Fish and Wildlife Service, the U.S. Forest Service, and other interested parties, to develop and implement air quality protection plans to reduce the pollution that causes visibility impairment. Five multi-state regional planning organizations (RPO) are working together to develop the technical basis for these plans.

Nebraska is part of the Central Regional Air Planning Association (CENRAP). CENRAP is an organization of states, tribes, federal agencies and other interested parties that identifies regional haze and visibility issues and develops strategies to address them. CENRAP is one of the five RPOs across the U.S. and includes the states and tribal areas of Nebraska, Kansas, Oklahoma, Texas, Minnesota, Iowa, Missouri, Arkansas, and Louisiana.

Regional Haze Rule & Best Available Retrofit Technology (BART)

Under the 1999 regional haze rule, states are required to set periodic goals for improving visibility in the 156 natural areas. As states work to reach these goals, they must develop regional haze implementation plans that contain enforceable measures and strategies for reducing visibility-impairing pollution. One requirement explicitly stated in the Clean Air Act of 1990 requires Best Available Retrofit Technology (BART) to be installed on units that meet specific applicability criteria. The applicability criteria for determining if a unit will be required to install BART controls are:
If the three criteria presented above are met, the source is considered to be BART eligible. In order to determine if the BART eligible units located at the source are subject to BART requirements, it must be demonstrated that emissions from the BART eligible units are anticipated to cause or contribute to any visibility impairment in Class I areas. This is done by conducting long-range transport air dispersion modeling to determine if emissions from the BART eligible units at a source will impair visibility in any Class I area more than 0.5 deciviews (a measurement of visibility impairment based on extinction of light).

States are required to identify the facilities that will have to reduce emissions under BART and then establish BART emission limits for those facilities. States must consider a number of factors when determining what affected sources are required to install for BART, including:

BART Permitting

On February 16, 2008, the Nebraska Air Quality Regulations, located in Title 129 of the Nebraska State Code, were revised in order to incorporated numerous changes, included the establishment of Chapter 43: Visibility Protection. This chapter incorporated the Regional Haze Rule by reference and required owners or operators of stationary sources subject to BART to prepare and submit a BART determination in accordance with the Regional Haze Rule. The rules also require the Department to issue a permit to the source in accordance with Title 129, Chapter 17, which is where construction permitting requirements are located. Since BART is required to be conducted, the BART decisions (i.e. the BART permits) will explicitly be included in Nebraska’s State Implementation Plan (SIP).

To facilitate the review of the BART permits and Regional Haze SIP, the Department has elected to provide select Regional Haze documents on the Department’s website. Additional public information is available by request at ndeq_records@ndeq.state.ne.us. Depending on the quantity and type of additional information requested, a fee may be assessed.

BART Related Information


Nebraska Department of Environmental Quality
1200 "N" Street, Suite 400
P.O. Box 98922
Lincoln, Nebraska 68509
(402) 471-2186