Wildfires spread smoke pollution over western US

Smoke pollution from wildfires raging in California and across the Pacific Northwest worsened in San Francisco, Seattle and Portland, Oregon, on Friday, giving those cities and others in the region some of the world's worst air quality. Public health officials warned residents to keep indoors with the windows shut, to set air conditioners to run on recirculated air instead of fresh, and to use air purifiers if they had them. Meanwhile, they wrestled with whether to open "smoke shelters" for homeless people or others lacking access to clean air amid the COVID-19 pandemic and concerns about herding people indoors. The smoke was expected to linger through the weekend.