Portland had an air quality index of over 200 on Friday — more than that of any other major city in the world, according to IQAir, a Swiss air quality technology company that operates a real-time air pollution monitoring platform.
Seattle ranked second, with an AQI of around 190.
Vancouver, British Columbia, came in third, and San Francisco took fourth place. Both cities had AQIs above 180.
Entire West Coast trapped in unhealthy and hazardous air. Seems like a big story. pic.twitter.com/EmFkE3v1lS
— Rachael Horwitz (@RachaelRad) September 11, 2020
An AQI measurement of zero to 50 is considered good. One of 50 to 100 is moderate. An index of 100 to 150 is unhealthy for sensitive groups, and over 150 is unhealthy for everyone. Over 200 is considered very unhealthy.
Officials urged residents in polluted areas to stay indoors as much as possible while air quality remains poor.
Portland's air quality remains unhealthy due to wildfire smoke. An @OregonDEQ air advisory is in effect until noon on Monday. Limit outdoor activities, and follow medical advice if you have a heart or lung condition. #OregonFires2020 https://t.co/ayE76m9Pe6
— PortlandBEM (@PortlandBEM) September 11, 2020 RELATED… Climate Change-Fueled Fires Are Changing The Way Californians Live Police Forced To Debunk Rumor That Antifa Started Massive Wildfires 500,000 Oregon Residents Evacuate Statewide Due To Wildfires testPromoTitleReplace testPromoDekReplace Join HuffPost Today! No thanks. Important conversations are happening now. Add your voice! Join HuffPost Today! Download Calling all HuffPost superfans! Sign up for membership to become a founding member and help shape HuffPost’s next chapter Join HuffPost