BEIJING - The downpour that washed out Olympic events in tennis, archery and rowing on Sunday also cleared up much of Beijing's dirty air.
On Monday, the city's air pollution levels dropped by more than half, registering a level of 38 -- falling within the World Health Organization's guidelines for healthy air. It was the first significant drop in the air pollution index since the beginning of August.
Heavy rains that drenched the city on Sunday continued into Monday with sporadic showers, replacing the recent hot and muggy patch of weather with cooler temperatures averaging 25 C, though humidity remained relatively high.
Beijing's notorious pollution has been a concern for Olympic organizers and U.S. athletes from the start. Chinese officials have taken drastic measures to curb the sources of pollutants, shutting down scores of factories, stopping constructions and removing two million vehicles from the road for a two-month period.
The effect has been far less than what China had hoped for. Since the measures began on July 20, Beijing has only seen a handful of days where the level of particulate matter -- tiny dust particles that are the worst pollutant -- was within the range of what the WHO considers healthy.
The Associated Press has been taking independent air samples from the Olympic Green, the primary sports thoroughfare, since mid-July. Readings on Monday showed a huge drop in particulate concentration from the day before, though levels remained three times higher than Beijing's official numbers.
Experts have said polluted air is unlikely to cause long-term damage to athletes' health, though it can exacerbate problems for those with asthma or allergies. The biggest concern has been whether performance could be hurt.
U.S. tennis player Sam Querrey said the air quality on Monday wasn't a factor in his match, but he said it could create issues for those playing both singles and doubles on the same day.
"I think the rain this last day and a half helped. But the first two days when we got here, I was struggling with the pollution, the heat, the humidity,'' Querrey said. "You could really feel it in your lungs when you started to breathe heavily.''
Querrey said he has been struck by the visible smog that settled over the city for the past week.
"I did not think it was going to be like that. I have yet to see blue sky or sun. I thought maybe there was going to be a small smog layer in patches, but it's literally a haze,'' he said.
Other athletes said they have had no choice but to cope.
"We've managed to adapt to the situation from home to China,'' said Siboniso Cele of South Africa, who is competing in slalom canoe. "There is some pollution, but for me, everything about the environment, I just take it out. I don't want an excuse. I can't control the environment and the pollution. I haven't tried any different things (like a mask) because in the race you have to do the race without the mask.''
Great Britain's field hockey captain, Ben Hawes, took it in stride, pointing out that the air quality affects everyone equally. "Both teams were breathing the same air. We were more concerned with the heat and humidity,'' he said.
That sentiment was echoed by tennis star Rafael Nadal of Spain, who was so soaked with sweat during his match Monday that he left a wet patch on the concrete during a tumble.
"The problem is the humidity, no?'' he said. "The (truth), I didn't feel nothing (from) the pollution. That didn't affect ... me. The problem is the humidity. I had to change the shirt every 10 minutes.''
