The “big picture” of air quality in the Four Corners appears murkier than the horizon on a windy day. That was the conclusion to be drawn from a regional air-quality conference that took place in mid-September at Fort Lewis College.
But one thing emerged sharp and clear from the discussions: The region’s air quality is worse than it ought to be, though finding specific culprits would stymie Sherlock Holmes.
In some ways, regional air quality is good. Mike Silverstein, planning and policy program manager for the Air Pollution Control Division of the Colorado Department of Public Health and Environment, said particulates — solid particles such as dust — are relatively low in Southwest Colorado.
“You don’t violate any of the national ambient air-quality standards,” he said.
Particulates are produced by wildfires, road dust, auto exhaust, and wood-burning stoves. Measures that reduce particulates include roadsweeping, the use of de-icers other than sand, modern wood stoves, and anti-idling ordinances. “We have a lot of diesel vehicles that folks just leave running,” Silverstein said.
But the picture for ozone is less rosy. Although ozone in the stratosphere high above the earth is beneficial, ozone at ground level is a known lung irritant and a factor in asthma, reduced lung capacity, and increased susceptibility to respiratory illness, Silverstein said.
Ozone, which is produced by a complex interaction of sunlight and emissions from engines, power plants and even paints, is “a regional pollutant,” Silverstein said. “A lot is transported in from other Western states and also from Asia.”
Ozone levels in Southwest Colorado generally hover below the federal standard of 85 parts per billion, the level at which significant health effects may occur, but occasionally spike above that. The levels are, on average, about 20 percent less than those in Denver, he said, but an audience member noted that that is high for a sparselypopulated area.
“I don’t think the West is rural any more,” Silverstein responded. Monitors record ozone at sites around the Four Corners, including Mesa Verde, the San Juan power plant west of Farmington and Bloomfield.
Currently, Mesa Verde averages about 69 ppb, a level which the Environmental Protection Agency calls “moderate.” Levels lower than 65 ppb are considered “good.”
The three-year average at the New Mexico sites has been around 76 ppb. “There are health issues at levels below the federal standard,” Silverstein warned.
Erik Aaboe of the New Mexico Environment Department said ozone has been an issue in the Four Corners ever since the federal standard was revised and monitoring began.
“We didn’t really anticipate high ozone levels here because, traditionally, problem areas have 10, 20, 50 times as many people,” he said. Ozone is much higher here than it should be, given the low population density.
“We really have to be concerned because there’s not a lot of headroom to degrade air quality further before health concerns become a real issue,” he said.
Mary Uhl, acting Albuquerque bureau chief of the New Mexico Environment Department, agreed. “Three or four years ago, we started noticing the upward trends in ozone at Farmington sites,” she said. “Those alarmed us. This is a relatively rural area and should have good air quality. Frankly, those levels are the kinds we might expect in Albuquerque.”
The concern prompted the NMED to enter into an Early Action Compact with the EPA and local officials to implement an air-quality improvement plan, she said. That plan was approved by the EPA this summer and is the first in the country.
The state of New Mexico then provided hundreds of thousands of dollars for a modeling analysis to study the impacts of the proposed Desert Rock and Peabody power plants, Uhl said. It also looked at oil and gas development in the northern San Juan Basin and Farmington.
The analysis projected increased nitrogen-oxide emissions but lower volatile organic compounds — compounds produced by gas wells and linked to ozone. The lower levels are predicted because of the playing out of some older oil and gas wells, Uhl said.
The analysis showed little overall effect from the coming power plants, Uhl said. “The new power plants and oil and gas will have little impact on ozone,” she said, because of decreases from other sources.
Mercury is another pollutant of particular concern in the Four Corners because of its toxicity. Released into the air by coal-burning and into the water through leaching from old mine sites, it is particularly damaging to infants and children. Silverstein said there are two mercury-monitoring sites in Colorado, one at Steamboat Springs, the other at Mesa Verde National Park. The latter has shown some of the highest depositions of mercury in the country.
He said an inter-agency Four Corners Air Quality Task Force is being developed to look at the cumulative effects of power plants as well as coalbed-methane drilling in the San Juan Basin.
The League of Women Voters of Montezuma County has expressed concern about air quality and mercury pollution and has called for more monitoring sites in the area.
But Silverstein voiced optimism about future air quality. “Projections are that emissions will be lessening from many sources,” he said.
