Visibility Protection and Haze

Visibility Basics

Visibility is degraded when light is scattered by tiny particles in the air, which reduces the clarity and color of what we see. This is referred to as haze and often happens when the air is humid. Haze degrades visibility in many American cities and scenic areas. Air pollutants that contribute to fine-particle formation and haze come from a variety of natural and manmade sources.

EPA’s Regional Haze Rule that was adopted in 1999, calls for state and federal agencies to work together to improve visibility in 156 national parks and wilderness areas [exit DNR] such as the Grand Canyon, Yosemite, the Great Smoky Mountains, and Shenandoah. These parks and pristine areas are called Class I Areas.

The haze rule requires that states, in coordination with the U.S. Environmental Protection Agency, the National Park Service, U.S. Fish and Wildlife Service, the U.S. Forest Service, and other interested parties, develop and implement air quality protection plans to reduce the pollution that degrades visibility. The overall goal is to eliminate the manmade effects on visibility by the year 2064. Interim milestones were established to insure that states are on track to meet the 2064 goal. The first State plans for regional haze were due in December 2007. Wisconsin has not yet submitted its haze plans but is working with surrounding states, federal land managers and tribes to develop the plans.

Visit EPA’s haze program [exit DNR] to learn more about the haze rule.

Regional Planning Organizations

Because regional haze can originate from sources located across large geographic areas, EPA has encouraged the States and Tribes to address visibility degradation from a regional perspective. Five regional planning organizations have been created to address regional haze.

Midwest Regional Planning Organization

Wisconsin is a member of the Midwest Regional Planning Organization (Midwest RPO) that was formed to facilitate regional planning to address the regional haze regulations adopted by the U.S. Environmental Protection Agency (USEPA) in 1999. The primary objective of the Midwest RPO is to assess both visibility impairment due to regional haze in the mandatory Federal Class I areas located inside the borders of the five States of Illinois, Indiana, Michigan, Ohio, and Wisconsin, and the impact of emissions from the five States on visibility impairment due to regional haze in the mandatory Federal Class I areas located outside the borders of the five States. Members of the Midwest RPO include the five States; tribes located within the five states; Federal Land Managers (U.S. National Park Service and U.S. Fish & Wildlife Service), and USEPA. For more information, please visit the Midwest Regional Planning Organization [exit DNR] web site.

• Visibility Improvement – State and Tribal Association of the Southeast [exit DNR]
• The Mid-Atlantic/Northeast Visibility Union [exit DNR]
• Western Regional Air Partnership [exit DNR]
• Central Regional Air Planning Association [exit DNR]

Improving Visibility

1. The costs of compliance
2. The energy and non-air quality environmental impacts of compliance
3. Any pollution control equipment in use at the source
4. The remaining useful life of the source

Wisconsin’s BART rule establishes a procedure for the determination of requirements to control SO2, NOx and particle pollution emissions from sources subject to BART, which are mainly boilers at electric generating power plants and at pulp and paper facilities. The electric generating power plants subject to BART do not need to install, operate, and maintain BART for SO2 and NOx controls if they are subject to the SO2 and NOx trading programs of the Clean Air Interstate Rule (CAIR).

Reasonable Progress

Wisconsin, as all other states, must develop a plan to address reasonable progress in all Class I areas where emissions from the state significantly contribute to visibility degradation. The purpose of reasonable progress is to insure that continuing progress is being made toward the 2064 visibility goal. The reasonable progress plan must address five factors which should be considered in evaluating potential emission control measures to meet visibility goals:

1. Cost of compliance
2. Time necessary for compliance
3. Energy and non-air quality environmental impacts of compliance
4. Remaining useful life of any existing source subject to such requirements
5. Uniform rate of progress

Regional Haze Consultation - Northern Class I Areas

The States of Michigan and Minnesota, along with representatives of other states including Wisconsin, tribal governments, and federal agencies, are working to address visibility impairment due to regional haze in four northern class I areas: Boundary Waters Canoe Wilderness Area, Voyageurs National Park, Isle Royale National Park, and Seney National Wilderness Area.

To support consultation in the development of reasonable progress plans for the Northern Class I Areas, the interested parties created a technical document that addresses the causes of visibility degradation in the area. The key findings of the document are as follows:

The chemical species which affect visibility impairment include ammonium sulfate and, to a lesser degree, ammonium nitrate and organic carbon.
• The pollutants and source sectors that contribute the most to visibility impairment include:
• SO2 emissions from electrical generating units (EGUs) (also referred to as power plants) and certain non-EGUs, which lead to sulfate formation.
• NOx emissions from a variety of sources such as motor vehicles, which lead to nitrate formation. Ammonia emissions from livestock waste and fertilizer applications are also important, especially for nitrate formation.
• Organic carbon concentrations which are thought to be mostly secondary organic aerosols of biogenic origin and, on an occasional episodic basis from fire activity.
• The source regions that contribute the most to visibility impairment are the States of Michigan, Minnesota, and Wisconsin. Other nearby states, including North Dakota, Iowa, and Illinois, also contribute to visibility impairment.
• Current (baseline) visibility levels are well above natural conditions

For more information, please visit the Haze Planning for the Northern Class I areas [exit DNR] web page.

Minnesota “Ask”

Through the regional consultation process, the Minnesota Pollution Control Agency (MPCA) determined that Wisconsin significantly contributes to visibility impairment at Boundary Waters Canoe Area Wilderness and Voyageurs National Park. MPCA “asked” the states that contribute to visibility impairment at those sites to consider the following control programs when developing their visibility plans:

• Implement BART
• Statewide Average Emission Rate for Power Plants to Match Minnesota’s Voluntary Emission Rates
• NOx – 0.25 lbs/mmBtu
• SO2 – 0.25 lbs/mmBtu
• Continued Assessment of Reasonable Measures for Industrial/Commercial/Institutional Boilers, Reciprocating Engines, and Turbines

For more information, see Minnesota’s regional haze plan [exit DNR].

Vermont “Ask”

Through the regional consultation process with MANE-VU, the State of Vermont determined that Wisconsin significantly contributes to visibility impairment at Lye Brook Wilderness Area. Vermont “asked” the states that contribute to visibility impairment at Lye Brook to consider the following control programs when developing their visibility plans:

• Implement BART
• 90% SO2 Reduction at Selected Power Plants
• Pleasant Prairie is the only identified power plant in Wisconsin and is already installing scrubbers that would meet that 90% goal.
• 28% SO2 Reduction from Non-Power Plant Sources
• The 28% reduction is relative to 2018 on-the-books emission projections.

For more information on Vermont’s regional haze plan, go to Summer Haze Event [exit DNR].