EUGENE, Ore. — Eugene looks a little like Beijing this week.

A milky haze has engulfed the city, offering perhaps a preview of the Summer Olympics in August.

With the U.S. Olympic track trials in full swing, the air quality in Oregon has turned murky, thanks to winds pushing up smoke from wildfires burning in Northern California.

The haze is expected to stick around for the rest of the week. Even a good thunderstorm might not be enough to disperse it.

"There's so much smoke that it would take a good front to pull it all the way through," said Jonathan Wolfe, a meteorologist with the National Weather Service in Portland. "There's a lot of pollutants in the air."

Sounds a lot like Beijing, where noxious pollution presents an enormous problem and a health menace. The city has started enacting a plan that will halt construction, close heavy industry and take vehicles off the road to cut back on emissions for the Summer Games.

Some athletes have expressed concern over the air quality, most notably Haile Gebrselassie, who has opted to skip the Olympic marathon and instead run in the 10,000-meter race.

American sprinter Lauryn Williams, who is worried about 10-second bursts more than daylong endurance runs, isn't fretting about pollution levels.

"I feel like as long as all eight lanes have to breathe it, then I'm OK with it," said Williams, who earned her Olympic spot in the 100 meters over the weekend. "Those people live over there their whole lives, that's their country, they live in it, and they're fine. I think one month in it is not going to kill us at all. I'm not worried about any of the different weather conditions."

The smoke began to blow into Eugene on Saturday, and soon sent the air quality index soaring to 140 as of Monday afternoon. That's considered an unhealthy level for sensitive groups, including those with asthma.

"What we've asked people to do is if they're in the sensitive group, avoid prolonged exercise activity outside," said Sally Markos, the public affairs spokesperson for Lane Regional Air Protection Agency. "Right now I'd tell people to use caution. It's going to affect individuals differently."

Some of the athletes said they were unaware of the cloud of smoke as they competed.

"(The smoke) was not a distraction at all," triple jumper Shakeema Welsch told The Register-Guard on Sunday. "The smoke didn't bother me at all."

Markos noticed the white haze growing thicker Sunday as she watched the trials, the hills in the background of Hayward Field slowly fading from sight.

"I got there about 11:30, and by 3 the hills had faded away," she said. "It changed the view."

The trials in Eugene also have seen unseasonably hot weather with highs creeping up into the 90s.

That's good practice, too, for what awaits in Beijing, where the average temperature in August is 85 degrees with plenty of humidity.

"That's going to be great for me," Williams said. "I live in Miami, I train at noon, so I'm ready for that as well."