188,940 Kids in Idaho are Breathing Unhealthy Levels of Air Pollution - Boise on Lists of Most Polluted Cities in Latest Lung Association “State of the Air” 2026 Report

Today, the American Lung Association released its 27th annual “State of the Air” report, which finds that nearly half of the children in the U.S. are breathing unhealthy levels of air pollution, including 188,940 kids in Idaho.The Boise-Mountain Home, ID area ranked 24th worst in the nation for ozone pollution and 17th worst in the nation for short-term particle pollution.

The Lung Association’s “State of the Air” report grades counties’ air quality in terms of unhealthy levels of ground-level ozone air pollution (also known as smog), and year-round and short-term spikes in particle pollution (also known as soot) over a three-year period (2022-2024). The report also ranks counties and metropolitan areas in cleanest and most polluted lists for each pollutant. Both ozone and particle pollution can cause premature death and other serious health effects such as asthma attacks, heart attacks and strokes, preterm births and impaired cognitive functioning later in life. Particle pollution can also cause lung cancer.

Infants, children and teens as a group are more susceptible to the health impacts of air pollution. Their lungs are still developing; they breathe more air for their body size than adults and they are frequently exposed to outdoor air. Air pollution exposure in childhood can cause long-term harm, including reduced lung growth, new asthma cases and increased risk of respiratory diseases.

“Clean air is essential to the health and wellbeing of families across Idaho. Children deserve to breathe air that won’t make them sick,” said Hether Kimmel, division director of health promotions and education for the American Lung Association. “Unfortunately, too many people in the Boise City-Mountain Home-Ontario, ID-OR metro area are living with unhealthy levels of ozone and particle pollution. This air pollution is causing kids to have asthma attacks, contributing to chronic health conditions, and making people who work outdoors sick.” 

Kimmel added: “To compound the issue further, the U.S. Environmental Protection Agency’s (EPA) rollbacks of critical healthy air rules are impacting our residents. We urge Idaho policymakers to take action to improve our air quality, and we are calling on everyone to tell EPA that our kids’ health counts.”

Nationally, the report found that 33.5 million children in the U.S., or 46% of people under 18 years old, live in an area that received a failing grade for at least one measure of air pollution. In total, 44% of people of all ages in the U.S. (152 million people in total) live in a county that received a failing grade for at least one measure of air pollution. 32.9 million people live in counties with failing grades for all three measures.

Key Findings for Boise City-Mountain Home-Ontario, ID-OR metro area:
Ground-level Ozone Pollution: 
Ozone “smog” affects the largest number of people in the U.S. Smog forms when gases from tailpipes, smokestacks, factories and other pollution sources react with sunlight. It is a powerful respiratory irritant with effects that have been likened to a sunburn of the lungs.  

• The Boise City-Mountain Home-Ontario, ID-OR metro area ranked 24th worst in the nation for ozone pollution.
  • The ranking was based on the area’s worst county’s average number of unhealthy days—10.3 days per year, an F grade, in Ada County, Idaho.
  • This was worse than the area's ranking in last year's report of 46th worst, with 5.7 days per year, an F grade.  

Particle Pollution: 
Fine particle pollution can be extremely dangerous and even deadly. These particles come from wildfires, wood-burning stoves, coal-fired power plants, diesel engines and other sources. The report has two grades for particle pollution: one for “short-term” particle pollution, or daily spikes, and one for the annual average “year-round” level that represents the concentration of particles in each location.

• The Boise City-Mountain Home-Ontario, ID-OR metro area ranked 17th worst in the nation for short-term particle pollution.
  • The ranking was based on the area’s worst county’s average number of unhealthy days—8.7 days per year, an F grade, in Canyon County, Idaho.
  • This was worse than the area's ranking in last year's report of 36th worst, with 4.8 days per year, an F grade.  
• For the year-round average level of particle pollution, the area’s worst county, Canyon County, Idaho, received a failing grade for pollution levels above the federal standard. 
  • The Boise City-Mountain Home-Ontario, ID-OR metro area ranked 49th worst in the nation.
  • This was worse than the area's ranking in last year's report of 77th worst in the nation. 

In addition to the Boise-Mountain Home-Ontario, ID-OR metro, other notable findings include the Idaho Falls-Rexburg-Blackfoot, ID metro area being ranked among the nation's cleanest cities for ozone pollution. The ranking was based on the area’s worst county’s average number of unhealthy days—0 days per year, an A grade, in Butte [Insert the word County if appropriate], Idaho. This was better than the area's ranking in last year's report of 165th worst, with 0.3 days per year, a B grade. 

The Idaho Falls-Rexburg-Blackfoot, ID metro area had no data collected for short-term particle pollution in this year's report. The metro area had no data collected for short-term particle pollution in last year's report. 

For the year-round average level of particle pollution, the metro area had no data collected to determine if it earned a passing grade with respect to the federal standard. The Idaho Falls-Rexburg-Blackfoot, ID metro area was therefore unranked in this year's report. In last year’s report, the metro area had no data collected to determine if it earned a passing grade with respect to the standard and was therefore unranked.

The Lung Association is calling on everyone to urge EPA to value the health of America’s kids. Historically, EPA has played an essential role in protecting people’s health from air pollution. The current EPA has retreated from its public health foundation by rolling back clean air protections. This EPA has also taken the recent step of eliminating health-related information from its economic analyses, meaning that the costs of pollution to kids, families and communities will not be counted as policies are undone. EPA must not devalue kids’ health.

See the full report results and take action at Lung.org/sota.