Denver experienced the worst air quality of any city in the world for several hours Saturday as heavy smoke from raging western wildfires polluted the city.
IQAir, a Swiss air quality technology company, determined that Denver’s air was the most polluted early Saturday at an Air Quality Index of 167. The measurement is by US standards, where a higher number indicates poorer air quality.
The company tracks the AQI for 94 major world cities. Later on Saturday, the city of Johannesburg, South Africa, moved to the top spot with a US AQI of 178.
The polluted air is a symptom of the 107 wildfires that are currently burning in the US and which have scorched 2.1 million acres as of Saturday, according to the National Interagency Fire Center.
David Zalubowski/AP
Smoke from western wildfires obscures the skyline of Denver on August 7, 2021.
And it’s likely that the drought conditions fueling the fires will get worse before they get better.
“The fire outlook continues to reflect warmer and drier conditions leading to the high potential for severe wildfire activity throughout the western United States through the rest of summer and into the fall. Widespread high temperatures observed across areas in the West and with periods of lightning activity continue to exacerbate the wildfire situation,” the NIFC said on its website.
The wildfire season has been devastating for California, where the Dixie Fire – the nation’s largest active fire – continues to grow and destroy anything in its path.
The fire, which is burning in four California counties, swelled to 447,723 acres Saturday and remains 21% contained, according to Cal Fire.
Five people who were missing after the fire tore through the historic town of Greenville, California, have been found safe, the Plumas County Sheriff’s Office announced Saturday. A total of 21 unaccounted-for people are now confirmed safe, while authorities are still searching for five others, the office said.
Greenville was nearly leveled when the fire swept through it. In the community’s commercial center at Main Street and State Route 89, nearly every business appeared to have collapsed or been gutted, with flames still flickering in the debris up and down the sides of both streets, video recorded Wednesday by storm chaser Brandon Clement showed.
Fires across the region prompted California’s Placer County Public Health and the Placer County Air Pollution Control District to issue an air quality advisory Thursday, forecasting hazardous smoke impacts and warning residents to stay indoors.
“Sad to say, the prediction is correct,” Ann Hobbs, associate planner at the Placer County Air Pollution Control District, told CNN. Hobbs said officials had anticipated a change in the wind would bring poor air quality and smoke to residents living in the area.
“Avoid all unnecessary outdoor activity,” said Hobbs, adding that the air quality is the worst the area has seen all year.
Photos: Wildfires raging in the West
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Flames from the Dixie Fire consume a pickup truck on Highway 89, south of Greenville, California, on Thursday, August 5.
Photos: Wildfires raging in the West
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Noah Berger/AP
Operations Chief Jay Walter passes the historic Sierra Lodge as the Dixie Fire burns through Greenville, California, on Wednesday, August 4. The fire leveled multiple historic buildings and dozens of homes in central Greenville.
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Firefighters work at a Greenville home that was engulfed by the Dixie Fire on August 4.
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The Dixie Fire burns near Taylorsville, California, on July 29.
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Sam Metz/AP
California Gov. Gavin Newsom, left, and Nevada Gov. Steve Sisolak tour an area destroyed by the Tamarack Fire in Gardnerville, Nevada, on July 28.
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Firefighter Brentt Call walks through a burned-over area of the Bootleg Fire near Klamath Falls, Oregon, on July 27.
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Cal Fire Capts. Tristan Gale, left, and Derek Leong monitor a firing operation in California’s Lassen National Forest on July 26. Crews had set a ground fire to stop the Dixie Fire from spreading.
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Firefighters try to reach a fire site in Quincy, California, on July 25.
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Volunteers sort clothing at a donation shelter for those affected by the Bootleg Fire in Bly, Oregon.
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Mathieu Lewis-Rolland/Reuters
Scott Griffin surveys his property, which was destroyed by the Bootleg Fire in Sycan Estates, Oregon.
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Noah Berger/AP
Flames consume a home as the Dixie Fire tears through the Indian Falls community of Plumas County, California, on July 24.
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August Frank/Lewiston Tribune/AP
People stand behind the fire line as flames from the Steptoe Canyon Fire spread through dry grass in Colton, Washington, on July 22.
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Plumes of smoke from the Dixie Fire rise above California’s Plumas National Forest, near the Pacific Gas and Electric Rock Creek Power House, on July 21.
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Ringo H.W. Chiu/AP
Firefighters walk near a wildfire in Topanga, California, on July 19.
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A firefighter does mop-up work in the Fremont-Winema National Forest, which has been struggling with the Bootleg Fire in Oregon.
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Nathan Howard/AP
A car is charred by the Bootleg Fire along a mountain road near Bly, Oregon.
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David Ryder/Reuters
Nicolas Bey, 11, hugs his father, Sayyid, near a donated trailer they are using after their home was burned in the Bootleg Fire near Beatty, Oregon.
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David Ryder/Reuters
Firefighters extinguish hot spots in an area affected by the Bootleg Fire near Bly, Oregon.
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Bryan Daniels/AP
A bear cub clings to a tree after being spotted by a safety officer at the Bootleg Fire in Oregon.
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Firefighters work to protect Markleeville, California, from the Tamarack Fire on July 17. The Tamarack Fire was started by a lightning strike.
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Ty O’Neil/SOPA Images/LightRocket via Getty Images
The Tamarack Fire burns in Markleeville, near the California-Nevada border, on July 17.
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David Ryder/Reuters
A member of the Northwest Incident Management Team 12 holds a map of the Chuweah Creek Fire as wildfires devastated Nespelem, Washington, on July 16.
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A cloud from the Bootleg Fire drifts into the air near Bly, Oregon, on July 16.
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Noah Berger/AP
Firefighters spray water from the Union Pacific Railroad’s fire train while battling the Dixie Fire in California’s Plumas National Forest on July 16.
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David Ryder/Reuters
Horses climb a hillside that was burned by the Chuweah Creek Fire in eastern Washington.
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Fire from the Bootleg Fire illuminates smoke near Bly, Oregon, on the night of July 16.
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US Forest Service/ZUMA Press Wire
A firefighter battles the Bootleg Fire in the Fremont-Winema National Forest, along the Oregon and California border, on July 15.
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Mathieu Lewis-Rolland/Reuters
A firefighting aircraft drops flame retardant on the Bootleg Fire in Bly, Oregon, on July 15.
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Pete Caster/Lewiston Tribune via AP
Firefighters dig away at hot spots underneath stumps and brush after flames from the Snake River Complex Fire swept through the area south of Lewiston, Idaho, on July 15.
Photos: Wildfires raging in the West
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David Ryder/Reuters
Burned cars sit outside a home that was destroyed by the Chuweah Creek Fire in Nespelem, Washington.
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Nathan Howard/AP
Evacuee Dee McCarley hugs her cat Bunny at a Red Cross center in Klamath Falls, Oregon, on July 14.
Photos: Wildfires raging in the West
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David Ryder/Reuters
An airplane drops fire retardant on the Chuweah Creek Fire in Washington on July 14.
Photos: Wildfires raging in the West
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Nathan Howard/AP
Operations Section Chief Bert Thayer examines a map of the Bootleg Fire in Chiloquin, Oregon, on July 13.
Photos: Wildfires raging in the West
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Noah Berger/AP
Fire consumes a home as the Sugar Fire, part of the Beckwourth Complex Fire, tears through Doyle, California, on July 10. It’s the second time in less than a year that the small town has been ravaged by a wildfire.
Photos: Wildfires raging in the West
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Mathieu Lewis-Rolland/Reuters
Men hug a member of the Red Cross at a Bootleg Fire evacuation center in Klamath Falls, Oregon.
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Noah Berger/AP
Embers blow across a field as the Sugar Fire burns in Doyle, California, on July 9.
Photos: Wildfires raging in the West
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Noah Berger/AP
Firefighters monitor the Sugar Fire in Doyle, California, on July 9.
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In this long-exposure photograph, taken early on July 2, flames surround a drought-stricken Shasta Lake during the Salt Fire in Lakehead, California.
Meanwhile, some areas within British Columbia are under evacuation orders or alerts as the White Rock Lake wildfire continues to spread, according to the British Columbia Wildfire Service.
The fire, burning near Vernon, has scorched about 135,900 acres. The city expanded its evacuation alert Friday night to include most of the city, according to a news release.
The expanded evacuation alert was made “out of an abundance of caution based on the advice of BC Wildfire due to increased fire activity and increased ember debris,” the City of Vernon tweeted.
Brisa Colon, Andy Rose and Camille Furst contributed to this report.