Air pollution in the Four Corners could face a tougher standard under the EPA's plan to strengthen national air quality.

The EPA is proposing to reduce allowable ground-level ozone levels from 75 parts per billion per eight-hour period to 65-70 parts per billion.

Since the current 75 ppb was set in 2008, thousands of new studies reviewed by the EPA show that exposure to the higher standard poses threats to respiratory health.

"Bringing ozone pollution standards in line with the latest science will clean up our air and protect those most at risk," said EPA Administrator Gina McCarthy. "Whether we work or play outdoors, we deserve to know the air we breathe is safe."

Ramifications for noncompliance could result in corrective action for states, and/or penalties such as less federal funding for projects.

"If the ozone ceiling is breached, the air quality standards could be imposed, which would mean the fossil fuel industries would have to clean up its act, and we would all have to reduce emissions," said Mike Eisenfeld, of the environmental group San Juan Citizens Alliance.

Ground-level ozone is a major contributor of smog. It forms when nitrogen oxides and volatile organic compounds are emitted from vehicles, industries, and power plants and combine in the atmosphere and are "cooked" in the sun.

People most at risk from breathing ozone include people with asthma, children, older adults and those who are active or work outside. The EPA says that stronger ozone standards also improve protection for low income and minority families who are more likely to live in communities overburdened by pollution.

"It's about time, and long overdue," said Eisenfeld. "Stricter ozone standards have been stalled for some time, and a lot of our communities are anxious about whether the air we breathe is healthy."

Emissions from oil-and-gas fields and coal-fired power plants in New Mexico contribute to a brown haze often visible to the south. A mysterious methane hot spot recently detected in the Four Corners also threatens air quality because it is a greenhouse gas.

"I don't think it's a coincidence that the methane bloom is right where energy production is concentrated," Eisenfeld said.

Proposed EPA ozone standards could cause Four Corners counties and local tribes to go out of compliance for air quality.

Depending if the standard is set at 65 ppb or 70 ppb, Montezuma and La Plata counties, Mesa Verde National Park, the Ute Mountain Tribe and Navajo Nation could be in violation, according to the EPA. San Juan County, Utah, and San Juan County, N.M., also could go out of compliance.

Based on data between 2011 and 2013, Montezuma County had an air-quality level of 69 ppb, measured at Mesa Verde National Park. For the same period, La Plata is rated at 72 ppb, San Juan County, Utah at 71 ppb, and the Navajo County, Ariz., at 70 ppb.

Visitors at Mesa Verde National Park notice the brown haze, and comment that clear skies are a quality they look for in their park experience, said natural resource manager George San Miguel.

"The park does not generate the level of pollution we record," he said, citing two coal-fired power plants nearby in New Mexico.

A plan to retire three of the most outdated generators at the Four Corners Power plant and update the remaining two is expected to improve air quality in the region.

"Air quality improvements projected to go into effect over the next 10 years show our ozone levels are expected to drop significantly thanks to improved emission controls," San Miguel said. "So if Montezuma County were to go into non-attainment in the near term, it looks like there is reason to believe the status would not last very long."

An EPA interactive map predicts that in 2025, La Plata County will have a air quality rating of 68 ppb, which would be over the limit if the standard is set at 65 ppb.

Across the U.S., based on 2011-2013 data, 358 counties would violate the 70 ppb, and additional 200 counties violate the 65 ppb. States would have until 2020 or 2037 to comply with the new standards.

Refineries and manufacturers are critical of the proposed stricter standards and say the costs will hurt the economy. The EPA is also taking comment on lowering the standard to 60 ppb for ozone. A National Association of Manufacturers report predicted that if the ozone standard is lowered to 60 parts per billion, it would cost the U.S. $270 billion a year.

Sen. James Inhofe, R-Okla., said the new EPA standard will be heavily scrutinized in the Congress.

"EPA's proposal to lower the Ozone National Ambient Air Quality Standard to between 65 parts per billion and 70 ppb will lower our nation's economic competitiveness and stifle job creation for decades," he said.

Written comments on this proposed EPA rule must be received by March 17, 2015.

jmimiaga@cortezjournal.com