Wildfires burning across the western United States will continue releasing smelly, harmful air until later in the week or after that, scientists say. They add that the smoky, cloud-covered skies might last even longer. People in Oregon, Washington and parts of California were struggling with yellowish-green smog caused by the fires. The air is the worst, most unhealthy air on the planet, by some measurements. The bad air is everywhere. It has entered homes and businesses. It caused the Oregon Zoo in Portland to close. No one can escape it. “I don’t think that we should be outside, but at the same time, we’ve been cooped up in the house already for months,” said Issa Ubidia-Luckett of Portland. “I mean, we shouldn’t be outside period.” Oregon’s Department of Environmental Quality extended its air quality warning until Thursday. It was supposed to end on Monday.