DENVER (CBS4) – Colorado’s Front Range is currently on track to again exceed the average number of Air Quality Alerts issued each summer. The combination of ozone and wildfire smoke have made Tuesday the 28th day this season with an alert.

(source: CBS)

The ozone monitoring season runs June 1 to August 31 and since alerts began to be issued in 2009, the Front Range has averaged about 35 alerts per season.

Recent years have seen higher numbers.

Last year there were 43 alert days while in 2018 there were 52. Both years had significant wildfires in Colorado and throughout the western U.S. The Camron Peak (208,663 acres), East Troublesome Fire (192,560 acres), and Pine Gulch (139,007 acres) wildfires that occurred in 2020 are the three largest in state history.

Ozone and wildfire smoke cause a very hazy sky over downtown Denver Tuesday morning (source: CBS)

According to Scott Landes, supervisor of the Meteorology and Prescribed Fire Unit at the Colorado Department of Public Health and Environment (CDPHE), ozone levels generally peak in mid to late July, then slowly subside in August. “That is climatology. During an active wildfire season all bets are off”, said Landes.

Therefore is seems very likely the 2021 air quality season will be considered worse than average with about 6 weeks left in the season and Denver only 7 days away from reaching the long-term average number of alert days.

The alert issued for the Denver metro area on Tuesday is primarily because of ozone. The is considered “unhealthy for sensitive groups” by the CDPHE meaning young children, older adults, and anyone with respiratory problems should avoid spending long periods of time outdoors again on Tuesday.

Similar air quality issues are expected likely each day through at least the upcoming weekend.

Tuesday will also be another hotter than normal day with high temperatures well into the 90s along the Front Range. The average high temperature in Denver for July 20 is 91 degrees.

Another hot day for most of Colorado on Tuesday (source: CBS)

Temperatures will decrease just slightly on Wednesday thanks to an increase in monsoon moisture and 30% chance for late day showers and thunderstorms in the metro area. The mountains have at least a 80% chance for afternoon and evening thunderstorms on Wednesday.

Meteorologist Ashton Altieri