Summer in Colorado usually means spending lots of time outdoors — biking, running and playing pickleball. This year, the smoke has been getting in the way.
For Fort Collins resident Ron Matthews, it has meant putting outdoor exercise on hold.
“It's prevented me from exercising outside,” Matthews said. “I have a little issue with asthma, and so I can't really road bike right now.”
In Arvada, Kendall Ross has had to routinely change his plans.
“We find ourselves wanting to take our bikes up to Golden, and just, well, we can't do that today,” Ross said. “Or even a stroll around City Park, or golf.”
His sister Renee, who had just flown in from Sacramento, said, “I noticed immediately the haze over the whole area ... I couldn't see the mountains.”
For Denver resident John Coleman, the bigger challenge is figuring out what's safe for his family.
“Do we want to subject a kid to the air quality there? Is it serious? Is it negligible? It's hard to rate that, measure it, and then apply it to your life,” Coleman said.
One way people are making those decisions is by checking the Air Quality Index on their phones. The AQI is a color-coded scale that shows how unhealthy the air is. It tracks pollutants such as ozone and fine particles, including those in wildfire smoke.
Delphine Farmer, a chemistry professor at Colorado State University, specializes in air quality. She said people shouldn’t rely only on what they can see or smell.
“When the AQI says it's unhealthy for sensitive groups, and it's orange, that's a really good indicator to start implementing some of those techniques to improve your air quality,” Farmer said.
She said orange is the cue to start taking precautions, such as closing windows or running an air purifier. Red and purple signal more serious conditions, when everyone — not just sensitive groups such as children, older adults or people with asthma — should limit their time outside.
Wildfire smoke is only one factor that can drive up the AQI.
“A really bad air quality day could be really high ozone, or it could be really high particulate matter, or it could be some moderate level of both,” Farmer said. “The AQI is going to have a balance of all of that.”
Ground-level ozone forms when pollutants from vehicles and industrial sources react in sunlight, a process intensified by heat.
That combination is especially apparent along the Front Range.
Colorado has struggled with dirty air for decades. Denver became the most visible symbol of the problem with its infamous brown cloud, a haze of pollution that was prominent from the 1960s through the 1980s.
That haze has improved over the decades because of stricter air pollution policies. But ozone levels remain a major issue along the Front Range.
“Wildfire smoke just adds a whole new dimension. It brings all those reactive organic compounds that were a key ingredient in making ozone,” Farmer said. “Once we get wildfire smoke added to the mix, it just accelerates that ozone production, and it makes the air quality even worse.”
What’s in that wildfire smoke depends on what’s burning. Trees and grass produce particles and gases, while homes and vehicles can add plastics, metals and other pollutants.
But what does all that exposure actually do to the body?
“Virtually every one of my patients came into clinic and were complaining that they were having more trouble with their breathing, with irritation to their eyes, to their throats, their nose,” said Dr. Lisa Maier, a pulmonologist at National Jewish Health.
Maier said wildfire smoke can worsen lung and heart disease and increase the risk of several types of cancer, even for people who feel healthy.
“It may start in the lungs, but these particles and these gases are small enough that they can get throughout the body and cause problems,” she said.
Researchers are still studying the health effects of prolonged wildfire smoke exposure. Maier said that the smoke can also take a mental toll by keeping people indoors and disrupting daily life.
Back in Denver, there is only so much adjusting Coleman can do.
“Can't sit inside all day every day. That's not why I moved to Colorado,” he said. “So you just kind of deal with it and more or less cross your fingers and hope for the best.”
For now, living with wildfire smoke in Colorado means checking the air quality, taking precautions and knowing when it's time to change your plans.
