More than double the number of air quality alerts were issued by the Mid-Ohio Regional Planning Commission from November 2024 through October 2025.
The regional planning commission said in its annual report released Tuesday that it issued eight air quality alerts during the period, compared to three the previous year.
The agency issues those alerts when ground-level ozone and particle pollution reach unhealthy levels.
Also, Columbus recorded a day where ozone levels were unhealthy for all residents, not just sensitive groups, on June 12, 2025. That was the first time that happened since 2012.
Weather conditions play a significant role in seasonal air quality trends. Warmer-than-average temperatures and below-normal precipitation during the year resulted in elevated ozone levels during the summer. Smoke from Canadian wildfires also affected air quality.
The report said that over the past 30 years, the number of high ozone days has declined across Ohio and neighboring states. That decline is driven mostly by emissions reductions.
However, there are annual variations in the number of high ozone days because of fluctuating weather conditions.