DENVER — The haze over Colorado’s national parks dissipated throughout the 1990s thanks to cooperation among Western states and cleaner power plants and fuels, a federal study shows.
The study will be presented Nov. 21 to the state Air Quality Control Commission.
But while the air is clearer, it is not necessarily cleaner.
Ozone and nitrogen deposits have crept up in Colorado the past few years, according to the report. In Rocky Mountain National Park, for instance, ozone levels are up nearly 30 percent, and in Mesa Verde National Park they are up 19 percent.
The progress of the 1990s could be difficult to sustain as more people, more cars and more need for power accompanies growth and development.
From 1990 to 2000, Colorado’s population swelled by nearly 1 million people, to 4.3 million. And a study by the University of Colorado’s Center of the American West estimates the population will grow to 6.2 million by 2050.
“It’s a little bit of a mixed story,” Vickie Patton, a lawyer for the Environmental Defense Fund office in Boulder, said of the Park Service’s report. “We’ve made some progress, but we clearly have our work cut out for us with these challenges.”
The stakes are high. Haze spoils scenic vistas, which can hurt tourism. Lousy air also hurts flora and fauna, as well as people, triggering asthma attacks and hastening deaths.
Haze happens when sunlight hits pollution particles, which either absorb the light or scatter it, shortening the view and muting colors.
The Park Service collected 10 years’ worth of data from three air monitors in Colorado.
While the report shows improvement in the degree of haziness for Rocky Mountain National Park and Great Sand Dunes National Monument, Mesa Verde National Park in southwestern Colorado is slipping.
Data on ozone was collected at Rocky Mountain National Park and Mesa Verde, and it showed both were experiencing increasing ozone.
Part of the problem in Mesa Verde may be pollution drifting to the area from San Juan County in northwestern New Mexico, a region on the verge of violating federal ozone standards.
Nationwide, air quality has improved or stayed the same in half of the 32 parks tested.
Still, Colorado’s national parks have a long way to go to fulfill the promise of the Environmental Protection Agency’s 1999 regional haze rule.