Heavy smoke from wildfires in the Pacific Northwest and Canada will adversely affect the air quality in Denver and along the Front Range for the foreseeable future, officials said Thursday.

Smoke carried by winds originating from the burning areas has been in Colorado for several months, but so far the particulates — soot, dust or ash — have had less impact on the air than high ozone levels. But that’s starting to change, said Dan Welsh, an air quality meteorologist with the Colorado Department of Public Health and Environment. 

“As the fires out west continue to flare and get larger, we’re seeing more of the impacts in addition to ozone, which is why we’ve upgraded to more advisories or action days for multiple pollutants as opposed to just ozone,” Welsh said. 

The air quality alert was in effect Thursday along the Front Range from Douglas County to Larimer and Weld counties. As the weekend continues haziness and smoke will trickle down the Interstate 25 corridor into Colorado Springs, said Evan Direnzo, a meteorologist with the National Weather Service Boulder. 

According to IQAir, a website that monitors air quality across the world, Denver had the seventh-worst air quality in the world as of Thursday afternoon.

Because of the poor quality of air, everyone should limit their time outdoors until the air quality improves, said Gregg Thomas, director for the environmental quality division with the Denver Department of Public Health and Environment. 

“There have been pretty detailed studies performed, including in the Denver region, that have linked high particulate pollution days to other issues like heart attacks,” Thomas said.

Even for those in perfect health will notice some effects of the poor quality of air, said Jonathan Samet, dean of the Colorado School of Public Health.

“Everyone’s going to notice this because the particles cause the haze and it can certainly be irritating and contribute to a cough or sore throat irritation,” he said.

Thomas and Samet said the best time for people to be outside is in the early morning hours when ozone levels are lower, but particulates can be high at all hours. 

Welsh said the smoky, poor air will remain in Colorado for a while. 

“Current projections are unfortunately showing more of the same for at least the foreseeable future,” Welsh said. “We are expecting an increase of wildfire smoke coming from the west Friday into Saturday, so we certainly are expecting to see some impacts, if not more impacts as we move through the weekend.”

The smoke will be a persistent problem that will only worsen in the years to come, experts said, and it will come to dominate more of the particulate matter polluting the air. As cars get cleaner and energy moves away from coal-fired power plants, smoke from wildfires in the West will become a larger contributor to poor air quality. Smoke is already impacting public health and will only get worse as time goes by, experts said.

Sheryl Magzamen, a Colorado State University researcher who has extensively studied air pollution and smoke exposure, said wildfire smoke is similar to other forms of air pollution. But it’s different, she continued, because it’s sporadic and random over an increasingly lengthy season.

While traffic pollution can be tracked and goes up and down reliably depending on the season, wildfire smoke is more random. What’s more, whether the state of Colorado has a bad fire season or not may not matter as smoke from fires on the West Coast drift to Colorado. That smoke is often more dangerous to inhale than “local” smoke, Magzamen said.

“The longer that these … particles reside in the atmosphere, the more stress they can cause when inhaled,” she said.

Denver and the Front Range in particular are at risk because, unlike many other places in the West and in Colorado, it’s densely populated, she said. Combine that with the presence of local fires and the travel from fires elsewhere, “you’ve got a lot of people hit with a lot of smoke.”

“The smoke is a silent epidemic,” which in Colorado has caused deaths and has exacerbated pre-existing conditions like asthma and COPD, she said.

Unlike technology that seeks to clean up car pollution or commitments to move away from coal-fired plants, there’s no policy levers that can quickly be pulled to mitigate smoke and wildfires, Magzamen said.

Public health officials are left only to respond, taking action such as pushing out messaging about the dangers of smoke and explaining how to build and use filters.

The increasing severity and prevalence of wildfires is a product of climate change, Magzamen and others say.

“Fires are tied to the drought in the West, and that’s all part and parcel of climate change,” she said. “We just have this system right now that’s spinning out of control. … We get smoke every summer now. If we stay in drought and if we just don’t have any mitigation plan for climate change in general, the cycle’s going to continue.”