In its yearly report, the American Lung Association gave La Plata County a failing grade for potentially dangerous ozone levels, likely a result of the region’s emissions from the oil and gas industry and surrounding power plants.

La Plata County, did, however, receive an “A” for particle pollution, which is tiny matter from sources such as diesel exhaust, wildfire smoke and dust that can bypass the body’s natural defense system and cause harm.

The report is called the “State of the Air.”

Janice Nolen, the ALA’s assistant vice president for national policy, said in an interview Tuesday that the rankings were based on the average of unhealthy ozone days from 2014 to 2016 according to the Environmental Protection Agency’s health quality index.

In La Plata County, the number of unhealthy ozone days has been steadily growing during that time frame, from one day in 2014, two days in 2015 and seven days in 2016, which was the second hottest year on record.

Looking at potential reasons for the unhealthy ozone days, Nolen said emissions from power plants and oil and gas operations, such as nitrogen oxides and methane, are usually the likely cause.

La Plata County, for instance, is home to and adjacent to one of the largest coalbed methane gas fields in the country and is also near two major coal power plants in New Mexico.

Emissions from those sources, coupled with increasingly warmer temperatures, are the ingredients for unhealthy ozone, Nolen said.

“It makes a good little bowl to cook ozone in,” she said.

Ozone can be particularly harmful to sensitive populations, such as senior citizens and children.

According to the ALA report, in La Plata County, there are more than 10,000 children younger than 18, nearly 8,625 people older than 65 and a total of 4,800 adults and children living with asthma.

“There’s a lot of people, even in La Plata County, potentially at risk for air pollution,” Nolen said.

Mark Salley, a spokesman with the Colorado Department of Public Health and Environment, provided a statement from the department that pointed out that while some Colorado counties received an “F” grade, they still meet the EPA’s standards.

La Plata County, for example, does meet the EPA’s air-quality standards set in 2015.

Nolen agreed. However, she said the ALA in its report counts the number of unhealthy days to let residents know about potential air pollution in their community, rather than dealing with standards. And, she said, the ALA would like to see more protective standards than the EPA.

Overall, however, both CDPHE and the ALA agree air quality is improving in Colorado.

“Colorado’s citizens are breathing air that is far cleaner of particle pollution than in years past,” CDPHE said in its statement. “These ozone declines have been in spite of a rapidly growing population and increased energy demand and production in Colorado.”

Nolen said the ALA agrees with this statement, adding that great strides have been made in recent years to improve air quality through reducing fossil fuel emissions and enforcing stricter environmental regulations.

But one of the points the report seeks to highlight, Nolen said, is that many of these measures that have helped improve air quality, and therefore human health, are at risk of being repealed.

The ALA says the Trump administration has continually sought to weaken the Clean Air Act, make budget cuts to projects that seek to improve air quality and has ignored scientific evidence on matters like climate change.

A new rule that would cut methane emissions from oil and gas activities on Bureau of Land Management lands, for instance, has continually been fought by the Trump administration.

But Nolen said those regulations would go a long way in improving air quality, especially in La Plata County, whose neighbor to the south, New Mexico, has lax regulations on methane waste.

“We’ve made a lot of improvements in the last few years,” Nolen said. “But we’re concerned to see those steps repealed or ignored.”

jromeo@durangoherald.com