Continued wildfires on the West Coast caused thick smog and orange skies in parts of California, Oregon and Washington this week.
Patrick Kenefick, left, and Dana Williams, both of Mill Valley, Calif., record the darkened Golden Gate Bridge covered with smoke from wildfires Wednesday, Sept. 9, 2020, from a pier at Fort Baker near Sausalito, Calif. The photo was taken at 9:47 a.m. in the morning.
This satellite image provided by the National Oceanic and Atmospheric Administration at 15:31 UTC (7:31 a.m. PDT) on Wednesday, Sept. 9, 2020, shows brown smoke from wildfires blowing westward, from California’s Sierra Nevada to the Coast Ranges, at center to left, and from Oregon at top left, affecting air quality throughout the West. Smoke mixes with clouds and overcast along the coast. Millions of acres of wildland and many homes and other structures have been lost to the flames.
Polo Salmon, left, and Bobby Slack, both of Vallejo, Calif., wait as they fish for rock crab from a pier at Fort Baker beneath the Golden Gate Bridge covered with smoke from wildfires, Wednesday morning, Sept. 9, 2020, near Sausalito, Calif.
San Francisco City Hall is shrouded in smoke from multiple wildfires burning in the Sierra Nevada and Coast Ranges of Northern California, Wednesday morning, Sept. 9, 2020. Air quality throughout the West was heavily impacted.
People look toward the skyline obscured by wildfire smoke in daytime from Kite Hill Open Space in San Francisco, Wednesday, Sept. 9, 2020.
Polo Salmon, left, and Bobby Slack, both of Vallejo, Calif., fish for rock crab from a pier at Fort Baker as smoke from wildfires darkens the morning sky Wednesday, Sept. 9, 2020, near Sausalito, Calif. In the background at left is Alcatraz Island.
A man walks along Bridgeway Avenue and looks out at the darkened morning sky with smoke from wildfires Wednesday, Sept. 9, 2020, in Sausalito, Calif.
A man walks his dog along Bridgeway Avenue as smoke from wildfires darken the morning Wednesday, Sept. 9, 2020, in Sausalito, Calif.
Wildfire smoke obscures the sky over Interstate 280 in San Francisco, Wednesday morning, Sept. 9, 2020.
A bicyclist rides past a seating area outside a wine bar as smoke from wildfires darken the morning sky Wednesday, Sept. 9, 2020, in Sausalito, Calif.
People look toward the skyline obscured by wildfire smoke during daytime from Kite Hill Open Space in San Francisco, Wednesday, Sept. 9, 2020.
A woman crosses a street by in front of a hotel as smoke from wildfires darken the morning sky Wednesday, Sept. 9, 2020, in Sausalito, Calif.
Wildfire smoke obscures the sky in the morning over San Francisco, Wednesday, Sept. 9, 2020.
According to Seattle-based KIRO-TV, the city’s air quality index reached 197 Friday morning. The capital city’s index reached 264 by Friday night.
That “very unhealthy” rating is a stark difference from the “good” rating measured by government agencies, which reported an index of 13 around the same time earlier Friday. In the evening, Beijing’s air quality index hit 32.
The air quality index ranges from 1 to 500. The higher the number, the unhealthier the air quality. According to the index, anything below 50 is considered good air quality. Ratings between 101 and 150 are considered unhealthy for vulnerable groups, such as children, the elderly and people with certain health conditions.
In Salem, Oregon, about 45 miles from Portland, the index reached a “hazardous” score of 428 Friday night.
Air quality was unhealthy in Los Angeles Friday night and very unhealthy in San Francisco.
Seattle Mayor Jenny Durkan declared all beaches, parks, boat launches and athletic fields closed through Sunday due to the poor air quality, KIRO-TV reported. Mayors in many California cities also restricted outdoor events.
Air quality improved in parts of China in the midst of the coronavirus pandemic after government-imposed shutdowns caused factories to close and commuters to stay home.
Learn more about air quality in different parts of the world here.