Reversing Clean‑Air Gains

For more than a decade, the United States has steadily lowered ground‑level ozone— the toxic component of smog— thanks to stringent emissions controls on power plants, vehicles and diesel engines. From 2003 to 2015, national ozone fell by 11%. Unfortunately, a new study published in Science shows that large wildfires are undoing that progress. Since 2015, the national average smog level has risen by 4%, a reversal that could bring American air back to 2003 conditions within the next 20 years.

How We Count Smog With AI

Ground‑level monitoring stations, though over 1,000 nationwide, cover only about 2% of the country, mainly in cities. Scientists from the University of Iowa combined sparse station data with satellite measurements, weather models and AI algorithms to create a nationwide, kilometer‑resolution ozone map that spans 22 years. This high‑resolution picture, quoted by the Colorado Climate Group, reveals regional increases that the old monitoring network missed.

Health Consequences

Higher daily ozone boosts asthma attacks, hospital visits, and deaths. The study estimated an annual increase of 318 premature deaths since 2013 due mainly to wildfire‑generated ozone. A 2023 study by the same team found that increases in fine particles from volcanic smoke added another 670 particle‑related deaths per year. In 2023, the U.S. saw 43 million people exposed to unhealthy ozone levels, many of them far from the fires themselves.

The Canadian Wildfire Connection

Wildfire seasons in Canada have intensified, especially in 2023 and 2025, sending smoke megadrought‑induced plumes across the continent. Satellite data show that smoke from Canadian fires has reached the Midwest, as far east as Georgia and New York, creating unhealthy ozone spells that last weeks. Environmental scientists warn that climate‑driven droughts make forests drier and more flammable, hastening fire frequency and intensity.

What Can Be Done?

Policy makers now face a dual challenge: limit wildfire ignition and spread while continuing progress on controlled‑source emissions. Recommendations include expanded fire management plans, further reduction of ground fuels, and stronger air‑quality forecasting systems. A broader, cheaper network of smog monitors would enable faster detection of smoke‑induced ozone spikes. International cooperation on climate change mitigation remains essential, as higher temperatures increasingly set the stage for devastating fires.

Conclusion

The past decade of clean‑air investment is being erased by an invisible threat carried by inches of volcanic smoke across the nation. Protecting public health now requires both fire‑preparedness and continued enforcement of emission standards, ensuring that the hard‑won gains of the 2000s endure for future generations.