Proposed federal regulations risk sullying the fresh air in the national parks - including Utah's Capitol Reef and Zion - says the National Parks Conservation Association.
"Right now, we're used to national parks in Utah that have pretty good air quality," said Karen Hevel-Mingo, who tracks air pollution and climate change with the group's Salt Lake City office.
"There's a real threat that's going to change."
The Washington-based group's new report, "Dark Horizons," identifies 10 national parks that are in the greatest danger of seeing their vistas sullied by the pollution from proposed coal-fired power plants. Meanwhile, the U.S. Environmental Protection Agency is poised to loosen clean-air standards now in place, the group contends.
For Capitol Reef, the NPCA points to the added pollution from two plants already approved by state regulators. Both permits have been challenged by environmental groups. Five other coal-fired plants already operate within 186 miles.
Near Zion National Park, three plants are under active development in a region where three are already pumping carbon dioxide, sulfur dioxide nitrous oxides and mercury into the air.
Hevel-Mingo said there's hope that efforts to cut greenhouse gas emissions in the region, including the Western Climate Initiative backed by Utah Gov. Jon Huntsman Jr., intended to help improve air quality. Meanwhile, she said, few park visitors realize the EPA's Washington headquarters has proposed standards that are aimed at reducing clean air protections.
"It's an awareness that needs to be improved in the Southwest," she said.
Cheryl Heying, director of the state's Division of Air Quality, noted that Utah regulators take care to follow state and federal air-quality standards with the parks in mind.
"We take our responsibility very seriously," she said. "We live here and we recreate here, and I personally hold the parks dear."
She noted the pollution that contributed to hazy vistas in the parks has been declining steadily.
"You're always going to get into that argument that it's never enough."