BEIJING — In the era of China's great dynasties, it was believed that emperors could command the heavens at will. They could summon rain when it was needed or clear the skies. China's ruling Communist Party would love to have similar powers. Clearly, it doesn't.
A defiant gray pall hung over Beijing on Thursday, one day ahead of the official start of the Summer Olympic Games, and the city's air-pollution index continued to inch up, as it has all week, despite a series of dramatic measures intended to cut contamination.
Chinese officials, the head of the International Olympic Committee and some athletes tried to play down concerns about air pollution. IOC Chairman Jacques Rogge called the haze "fog" and said that it wouldn't harm athletes.
But the city's air-pollution index stood at levels that were more than six times what the World Health Organization recommends for long-term exposure. The problem was visible to anyone who cared to see it. In many parts of the capital, one could barely see three or four city blocks Thursday. Relief, in the form of rain, wasn't likely before Monday or Tuesday.
"On a day like today, or two weekends ago when I first arrived, you can look directly at the sun without sunglasses and just see an orange orb," said Staci Simonich, an environmental and atmospheric chemist at Oregon State University who's testing air samples in Beijing during the games.
The air-pollution index reached 95 on Thursday, according to the Ministry of Environmental Protection's Web site. On Wednesday, the reading was 85. That's considered moderate. Anything over 100 is harmful to groups such as children and the elderly.
The smog has continued to thicken all week, after a brilliantly clear Sunday. The smog's persistence puzzled officials and analysts after the dramatic actions Chinese officials have taken to cut the haze ahead of the onset of competition.
Officials have ordered half of Beijing's vehicles from the streets, cutting the number in circulation by more than a million each day. They've shut down scores of factories.
Yet the problem persists.
Simonich said that much of the problem was Beijing's geography, which Chinese leaders really can't do anything about.
Beijing is set in a dry plain, with mountains on the north, east and west. "When we get wind from the south, it pushes pollution into Beijing," she said. On Thursday, the wind was out of the southeast.
The pollution comes from a variety of sources. Microscopic dust and soil particles occur naturally in Beijing's dry conditions, something that isn't likely to change no matter what Chinese leaders dictate, though they've made an effort, planting hundreds of thousands of trees on the plains outside the city. Some of the haze is caused by heat and humidity, combined with strong sunlight, which create a sauna effect. Fixing that, too, is beyond Chinese leaders' capacities.
Then there are particles from combustion sources such as automobiles, factories and power-generating plants. That's been the focus of Chinese efforts to cut down on pollution. But those efforts don't appear to have been enough to clear the air.
That's going to depend on Beijing getting some rain and a change in wind direction, which isn't likely before next week, when some rain is predicted for Monday or Tuesday. Until then, Beijing is predicted to be hot, humid and cloudy, just as on Thursday.
State television news coverage Thursday of the Olympic Games avoided long panning shots of the shrouded horizon, and IOC officials said they were prepared to suspend some competition events if pollution worsened. Rogge preferred to stress the "commendable effort" China has made in recent years to lessen sources of pollution.
"What they have done is extraordinary," he said, "You know what they've done: planting millions of trees between the Gobi desert and Beijing, removing hundreds of thousands of polluting cars, closing polluting petrol stations, switching from coal energy in the factories to gas energy that is less polluting (and) removing very polluting factories to other regions."
Rogge said pollution levels "are coming down. It is not yet perfect (but) it is safe for the athletes." Chinese sports officials say they have contingency plans for events that have to be postponed or moved to different locales, although they haven't offered details.
"The air quality is day by day," said Dexter Fowler, a member of the U.S. baseball team. "They say day by day it gets better and better. I'm just blessed with the efforts China has made to clear it up. I'm sure if it's that bad, we won't be out there."
Bob Watson, the general manager of the U.S. baseball team, said his players would compete regardless of the pollution.
"Everyone's going to play in it who plays outside," Watson said. "The government has spent a lot of money and there are a lot of smart brains working on pollution. But that's something out of your control. Everyone's playing on the same field, and we got to deal with it."
On Wednesday, star U.S. swimmer Michael Phelps said he wasn't concerned about air quality.
Still, the IOC has placed 27 stations around the Beijing area measuring sulfur dioxide, carbon monoxide and other contaminants.
Arne Ljungqvist, the head of the IOC's medical commission, said that since the measuring system began July 27, contaminant levels had dipped below the "interim target" where air quality was considered satisfactory for developing countries.
"Although the two first days suggested some measurements that were a little above interim targets, they have now gone down and they are steadily below the interim target with all the pollution data we are measuring, which to me is quite encouraging," Ljungqvist said.
He said the data bolstered an IOC finding in March that "we cannot see any real health risk for athletes coming to Beijing to compete."
But he also acknowledged that "some athletes may suffer from respiratory problems" under current conditions and that should air quality drop, "those respiratory problems" may increase.
Healthy enough or not, the haze can be disconcerting for visitors from cleaner locales.
"We don't ever experience this in Oregon, except maybe during bad forest fires," Simonich said.
"The biggest thing that could clear things up is rain and winds from the north," she said.