Ozone levels pressure Four Corners

Environmental Protection Agency proposes stricter air standards

The agency is proposing to tighten its "primary" ozone standard from 75 parts per billion to a level within the range of 60 ppb and 70 ppb.

The stricter standard is based on findings about the health effects of ozone, particularly on the elderly, children and people with respiratory problems.

"Children are at increased risk from exposure to ozone because their lungs are still developing and they are more likely to be active outdoors," an EPA fact sheet about the proposed standard says.

An air-quality report commissioned by La Plata County notes that most monitoring sites in the area have recorded levels at or above the proposed levels.

"Most, if not all, of monitoring sites in the Four Corners Region currently would be in violation of the new ozone NAAQS (national ambient air quality standards)," the report states.

John Molenar, who wrote the report and is an air-quality expert with Fort Collins-based Air Resource Specialists, said the lion's share of ozone-producing emissions in the region come from energy production, including natural-gas wells and two large-scale coal-fired power plants near Farmington.

Thousands of wells dot the northern San Juan Basin, a rich source of coal-bed methane. Meanwhile, the Four Corners Power Plant is one of the largest coal-fired generating stations in the U.S., and the San Juan Generating Station is the seventh largest in the West.

A third coal-fired plant, Desert Rock, has been proposed for the region but has struggled to obtain necessary regulatory approvals.

Vehicles and many other human activities also contribute.

The EPA is expected to announce its final decision about the standard in late summer. It will be the second time in about two years that the agency has imposed a more stringent limit.

In March 2008, the limit was moved from 84 ppb to the current level of 75 ppb despite a recommendation from the EPA's independent scientific advisory panel that it be lower still.

The Obama administration called for a new review, which led to the current proposal for tighter limits, said Mike Silverstein, deputy director of the Air Pollution Control Division at the state health department.

Silverstein said being classified as out of attainment is a "big deal" because it requires affected areas to come up with detailed plans for reducing emissions related to ozone.

Some of the remedies, such as retrofitting power plants with advanced emissions controls, can be costly.

"We have to figure out, strategically, where do we get the most bang for our buck," Silverstein said.

Molenar said ozone is the product of a complex interaction of factors, including climatology and geography. Some areas have naturally high ozone levels.

"It's not a linear thing," he said.

That can make solving the problem tricky.

The cost of either producing cleaner power or curtailing production will get passed on to consumers in the form of more expensive energy or fewer jobs.

"The bottom line is, we're going to pay for it," Molenar said.

And the most effectual measures, such as shutting down the coal-fired power plants, may be economically untenable.

Because of this, he said his personal opinion is that expectations for improvement must be reasonable.

"The best we're going to do anywhere in these oil- and gas-producing areas is maintain where we're at," he said. "I'm not sure it will ever come down."