BEIJING (AP) After all the worries about Beijing's pollution, in the end, withering heat and humidity took a greater toll on Olympic athletes.
Saturday marked the first outdoor endurance competition of the games - the grueling 152-mile men's cycling road race that started at the historic Temple of Heaven and wound up at the Great Wall.
The capital's thick haze from the last few days lifted a bit, allowing sunlight through as riders wound their way through the sweltering 6½-hour race over the hilly course.
"It was a lot better than I expected, really," U.S. cyclist Jason McCartney said. "The first couple days training here, it was just kind of like, whoa. But today, maybe the air was a little bit thinner. It wasn't crazy bad for us."
What was bad, however, was the heat, and the accompanying humidity resulted in a heat index of 90 degrees. Several riders surrendered long before the gold medal was decided, simply not having the energy to finish the race.
"The conditions were just so humid and so hot, it was just a real war of attrition today," said Michael Rogers of Australia, who tied for fifth place.
Belgium's Maxime Montfort simply gasped: "It's too hard. Too hard. Too hard."
Beijing's air pollution index logged in at 79, a drop from the day before, though still higher than what the World Health Organization considers healthy. China considers levels between 51-100 to be moderate pollution, and anything more than 100 as harmful to sensitive groups, including children and the elderly.
The Associated Press has conducted its own snapshot readings since mid-July taken from the Olympic Green of Beijing's worst pollutant - tiny dust particles known as particulate matter 10. The independent spot check on Saturday showed a level of 147 micrograms per cubic meter, reflecting a big drop in PM 10 concentration and an increase in visibility.
Officials at the International Olympic Committee have been particularly concerned about the impact of pollution on endurance sports, like the marathon and cycling, that last more than an hour.
The city's notoriously polluted air, one of the biggest worries for Olympic organizers, had prompted drastic measures ahead of the games, including pulling half of Beijing's 3.3 million vehicles off the road, halting most construction and closing some factories in the capital and surrounding provinces.
Health experts say there is little risk to athletes and visitors of long-term damage from breathing polluted air for a couple weeks. However, athletes who are exercising tend to breathe very heavily, thereby inhaling more amounts of dirty air, which can cause some temporary respiratory problems.
"It's mainly about performance," said Patrick Kinney, an epidemiologist at Columbia University who has conducted studies on the effects of pollution. "Will they be able to perform up to the level of their conditioning, given the pollution? It's less about long-term health risks. That's not the issue."
IOC officials said this week they believe air quality to be safe for athletes but added they would monitor pollution levels hourly. Competitions could be postponed or rescheduled if smog levels were too high. Air quality was being monitored on an hourly basis at 21 stations.
At the beach volleyball venue in Chaoyang Park, those in the crowd tried to cool themselves with handheld fans or misters stationed around the concourse. President Bush stopped by, his back soaked with sweat while he offered encouragement to the U.S. players on the practice court.
The heat was too much for most to stick around for the six-hour session, and the venue largely cleared out after the Chinese match in the middle of the morning. In the media area, empty water bottles stacked up on the tables.
Andrew Schacht, a volleyball player from Australia, said the team had tried to get ready for Beijing's muggy August weather.
"We were preparing for the conditions from hell," he said. "We tried very hard to work out in the worst part of the day, and we stayed out there when it was hottest."
On Saturday, temperatures obliged, rising to an average of 90 degrees with 94 percent humidity.
Samuel Sanchez of Spain won the men's cycling with a furious sprint at the end. He said conditions pushed him to the limit.
"The heat and humidity were extreme," he said. "I was saving my legs for that final lap."
By the end of the day, there was still enough haze to obscure part of the panoramic finish-line views of the Great Wall.