Four US Olympic cyclists who arrived for the Beijing Games wearing breathing masks have apologised for their actions, clearing some of the bad air generated by fears about pollution.
Organisers of the Games in the sprawling metropolis of 15 million people crossed their fingers with two days to go to tomorrow's opening ceremony, which China fervently hopes will see fireworks flashing up into clear evening skies.
But a stubborn haze persisted over the city yesterday, drawing a gray veil over a skyline that sprouts new high-rise blocks as China's economic boom continues to reverberate.
Hot, humid air with the temperature hitting 34°C kept a muggy lid over the city, which has already pulled millions of cars off the roads and halted factory production to improve air quality. But meteorologists said chances of the haze lifting over the next two days were good.
A storm in the South China Sea was approaching Hong Kong, where Olympic equestrian events are scheduled to start on Saturday and might have to be delayed.
But "severe" Tropical Storm Kammuri could bring welcome rain later to Beijing, perhaps washing the skies clean for tomorrow.
Senior US Olympic Committee official Jim Scherr said the Olympic cyclists who landed at Beijing airport wearing black respiratory masks had been "a little bit overcautious".
"Those athletes regret that action and they have written an apology to BOCOG (Beijing organising committee) on their own behalf," he told a news conference.
But Mr Scherr confirmed that about one third of the US team - or some 200 athletes - had been issued with the same type of mask prior to arrival in China and would not be prevented from using them if they saw the need.
Athletes were understandably concerned about anything that might impair their performance in sports where a few hundredths of a second can separate gold from fourth place, he noted.
Beijing has shut factories, pulled cars from its roads and spent 120 billion yuan (€11.298) to combat chronic pollution and ensure smog does not shroud the August 8-24 Olympics.
The city is holding off on plans to ground more cars and close more factories, hoping the weather will clear by itself.
"We haven't been told to implement any additional measures," commented Li Jianguo, deputy director of the Beijing Municipal Bureau of Communications. Germany's sporting director Bernhard Schwank said the conditions were as expected.
"A lot of athletes have been moaning and groaning when they they first got off their airplanes and got their first feel of it, but most of those here have already grown accustomed to the conditions," Mr Schwank said.
"So far, there have been no health complaints."
The Athens 2004 Games were also plagued in advance by fears that summer smog, heat and humidity would make them the hottest in modern history, with temperatures of 24-34°C. Late summer sea winds off the Mediterranean helped sweep away pollution, alleviating the worst smog fears.
Heading for the Los Angeles Olympics 20 years earlier, before the world started taking pollution seriously, Britain's equestrian team wanted to take oxygen masks for their horses.
Some athletes in Beijing were taking the muggy conditions in their stride.
"We'd been told it was absolutely terrible so we were prepared for much worse," said Renata Ribeiro, a Brazilian beach volleyball player. "It's actually not that heavy today."
Factbox - How past Olympics fought their smog
Athens, August 13-29, 2004:
Typically polluted and hot in July and August, Athens feared summer smog and Mediterranean heat and humidity would make the Games the hottest in modern history, with expected temperatures of 24-34°C.
• The Greek capital expanded its metro, built a new tramway, and used natural gas powered buses to combat air pollution. Thousands of trees were plan-ted and factories closed for August.
• An uncovered swimming pool, the first roof-less Olympic pool since Barcelona in 1992, caused pre-Games uproar among swimmers fearing summer heat. Officials said cold water would be added if water temperatures exceeded 2°C.
• Hoped-for late summer sea winds off the Mediterranean helped sweep away pollution, alleviating Athens' worst smog fears.
Atlanta, July 19-August 4, 1996
Summertime ozone pollution was one of officials' biggest fears as hot, humid Atlanta prepared for the Games.
• At the time the city's ozone readings exceeded federal standards by about 12 days each year, due to emissions from cars, trucks and power plants during hot summer months.
• About 30,000 trees were planted, car-pool lanes added to highways, traffic banned from downtown, and local businesses allowed telecommuting to clear the air and reduce congestion.
• Bus and rail fare was included in Olympic ticket prices and about 5,200 natural gas buses - the first alternative fuel fleet to be used at an Olympic Games - were deployed.
The mass-transit push overcrowded subways, and strained the bus system, but along with fresh winds it also helped lower air pollution, officials concluded.
Los Angeles, July 28-August 12, 1984
Set in a coastal basin that traps smog, the city of angels issued dozens of smog alerts and sank under its worst brown haze in a decade just weeks before the Games. Britain's equestrian team said they would take oxygen masks for their horses.
• About 4,000 big businesses and industries, including refineries and chemical plants, were asked to voluntarily cut production by 10 to 20 per cent during the Games.
• Men's and women's marathons were run in the early morning and late afternoon when smog levels are lower, and were routed through beach communities rarely affected by air pollution.
• Spectators took Olympic buses and commuters worked different hours, used car pools or took holidays to lessen pollution from industry and the city's five million cars.
• The Games' first week saw "abnormally healthy" air, local media said. Smog levels climbed later as traffic picked up.
In one pre-Games dud note, the death of Bomber, a bald eagle being trained to star in the opening ceremony, was blamed partially on smog-induced lung damage.