EUGENE, Ore. -- Olympic hopes also come with Olympic fears. Beijing in China is famous for its air pollution, and concerns about the impact on athletes have been the subject of scientific papers and news reports.
The U.S. Track and Field team may have an edge after competing in Eugene, routinely the nation's worst city for allergens like pollen. LATEST POLLEN COUNTS
And Steve Prefontaine famously finished the mile in 1974 by hacking up blood after inhaling the smoke-filled air for the duration of the race.
Field burning season was delayed this year by order of the governor to accomodate the Olympic Track and Field Trials.
Organizers also tried to time the event to avoid allergy season.
Allergist Kraig Jacobson advised Olympic track officials that Eugene's grass season is usually about over by the end of June.
"We thought we were safe," he said.
But this year the cold spring delayed the season by two weeks.
"This is the latest of 31 years," Jacobson said. "It doesn't take much in the lungs to make a difference between being able to win a race and not even being able to complete a race."
Brad Hudson is coaching four runners competing in the trials.
"Not everyone's allergic but the one's who are are prepared with the medicine and they're going to stay out of here until the last minute," he said. "It's kind of just another element, that's what running is."
Track athletes are allowed to take anti-histimines like Claritin and Allegra, but that medicine may not make a dent in fighting off a high pollen count.
Athletes with medically proven asthma can take inhalable medication with steroids but only if they have an exemption from the track and field officials.