San Juan County again gets failing grade for air quality

American Lung Association issues annual report

Mike Easterling
Farmington Daily Times
San Juan County again has drawn a failing grade for ozone smog from the American Lung Association in its annual report on air quality.
  • This is the second year in a row and 15th time in 20 years San Juan County has gotten an F.
  • This year's grade reflects data accumulated from 2017 to 2019.
  • San Juan County was one of six counties in the state to be assessed an F grade for ozone smog.

FARMINGTON — The American Lung Association's annual State of the Air report has found that ozone, or smog, levels in San Juan County are unacceptably high, earning the county a failing grade for the second year in a row .

The April 21 report assigned San Juan County a grade of F for its weighted average of 7.0 due to its number of high ozone days per year. The grade reflects data accumulated from 2017 to 2019, the most recent period from which the information was available. Any score of 3.2 or less is considered a passing grade.

On the positive side, that 7.0 figure represented a decline from last year's number, which covered the period from 2016 to 2018, when the county earned a score of 7.7. That weighted average also got the county a failing grade of F.

San Juan County was one of six counties in the state to be assessed an F grade for ozone smog, joining Eddy, Lea, Doña Ana, Bernalillo and Sandoval counties. Eddy County's score of 17.2 qualified it as the 24th most polluted county in the country for ozone smog and made it one of only two rural counties included in that group.

Lea County had a weighted average of 4.0 for 2017-2019, marking the first time since 2009 — when the 2005-2007 data was analyzed — that its ozone level exceeded the 3.2 mark required for a passing grade.

An ALA press release says the failing grades for San Juan, Eddy and Lea counties are related to oil and gas production. Three other counties in the state — Doña Ana (22.5), Bernalillo (7.7) and Sandoval (4.3) — also received failing grades for ozone smog. But the organization states that transportation is likely the driving factor behind the scores for Doña Ana and Bernalillo counties.

Overall, New Mexico earned an F grade for ozone smog.

The ozone smog content of San Juan County's air has varied widely over the last 20 years, according to an annual report by the American Lung Association.

This year's figure for San Juan County represents a continuation of its peaks-and-valleys trend over the last 20 years. The county's yearly weighted average has risen and fallen repeatedly, climbing steadily from the 1997-1999 period (2.0) to a high of 21.3 from 2000-2002.

The number then fell for the next three years, reaching a valley of 8.7 days for 2003-2005, before rising to another high of 23.8 days from 2005-2007. San Juan County's weighted averaged then plunged to a low of 1.3 days for 2008-2010 before beginning another upward trend over the next three years. That increase peaked at 9.7 days for 2011-2013, then the county saw a three-year downward trend that reached a low point of 1.3 days for 2014-2016.

For the 2013-2015, 2014-2016 and 2015-2017 periods, San Juan County received a passing grade for ozone smog. But over the last 20 years, the county has achieved that distinction only five times.

The ALA website describes ozone smog as one of the most dangerous and widespread pollutants in the country. The organization says it develops in the atmosphere from gases that emerge from tailpipes, smokestacks and other sources. Ozone smog is formed when those gases mix with sunlight.

The State of the Air report also includes analyses of particle air pollution, also known as soot, but San Juan County did not register a grade or a score in that area because monitors for those pollutants do not exist here.

The ALA has issued its State of the Air report annually since the year 2000. The full report can be accessed at under the "What's the State of Your Air?" header.

Mike Easterling can be reached at 505-564-4610 or Support local journalism with a digital subscription.