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The Regional Haze Rule requires states to improve visibility in our nation's national parks and wildernesses (Class I areas) and restore them to natural visibility conditions by 2064.

The federal Interagency Monitoring of Protected Visual Environments (IMPROVE) program provides long term monitoring to track changes in visibility and help identify causes of visibility impairment. The IMPROVE program currently consists of over 100 monitoring sites for Class I areas; Minnesota has two monitors in the IMPROVE program that represent Boundary Waters Canoe Area Wilderness (BWCA) and Voyageurs National Park. A Michigan Class I area, Isle Royale National Park, lies close to the Minnesota border on an island in Lake Superior. This IMPROVE program monitor resides in the Michigan Upper Peninsula for accessibility.

Minnesota, in partnership with other states, tribes and federal entities, use models that can simulate atmospheric chemistry and the transport of visibility impairing pollutants over long distances to help plan what emissions reductions can further improve visibility, and establish interim goals. We need to do more to achieve natural visibility conditions in Minnesota Class I areas.

Monitoring data

The monitoring data shows striking visibility improvements in Minnesota and elsewhere that can be attributed to the Clean Air Act and Regional Haze Program, as well as other efforts that led to reductions in emissions of the pollutants that impair visibility. Both the BWCA and Voyageurs National Park have achieved the 2018 interim progress goals toward natural visibility conditions.

Explore visibility data for Minnesota Class I areas

This interactive tool shows the progress made toward interim goals for visibility, components of impaired visibility, and regional influences on the air in Minnesota Class I areas.

Explore visibility data

Emissions data

The atmospheric chemistry and transport model requires emissions input to simulate visibility improvement projections. Interim goals for 2028 are based on national and international emissions developed for year 2016 and projected to 2028.

Explore emissions inputs for modeling Minnesota 2028 interim visibility goals

This interactive tool shows the emissions input to the atmospheric chemistry model to develop our visibility goals at Minnesota Class I areas.

Interactive model