BEIJING - The International Olympic Committee on Thursday ruled out shifting events away from Beijing during next year's Olympics due to the city's foul air, though it and the United Nations cited pollution as a major concern.

With 10 months to go before next August's games, air pollution has emerged as one of Beijing's biggest problems in its generally smooth preparations.  The United Nations Environment Program criticized Beijing's progress on cleaning its air as slow and said some pollution exceeded World Health Organization standards.

In an overall positive assessment of Beijing's preparations, an IOC inspection team said air quality was a leading concern and that it was monitoring the situation day-to-day. The inspection team leader, Hein Verbruggen, said the impact of pollution on athletes' performance was a particular concern.

IOC president Jacques Rogge has warned in the past that the severe air pollution might force some outdoor endurance events to be delayed.

The IOC inspectors acknowledged some events might be rescheduled for a few days but expressed confidence that special measures would clear the air.

"The air quality is a big problem. You might wait a day or two but it is something that we're used to,'' Verbruggen told reporters. "It is a normal standard procedure that we have.''

The acknowledgment underscored the dwindling options organizers face as the Aug. 8-24 Olympics draw nearer.  Some countries are delaying their teams' arrivals in Beijing until the last possible moment to protect their athletes' performance.

China has one of the world's fastest-growing economies, but its cities are paying for it with choking pollution.  Beijing is often blanketed by a gray haze, some from coal-fired industries, others from the soaring numbers of cars.

"Extensive use of coal, the city's geographical location and a growing number of motor vehicles means the pace of improvement in Beijing's air quality is slow,'' Eric Falt, who heads the UN Environment Program's sports and environment project, told reporters at a separate event to release the agency's report card on Beijing's air.

Falt said small particulate matter -- fine particles of pollution that are harmful to human health -- were "particularly worrying.''

The UN report found that the average level of small particulate matter in Beijing's air in 2006 was eight times higher than the level recommended by the World Health Organization.

Other forms of air pollution -- sulfur dioxide, nitrogen dioxide and carbon monoxide -- rose or failed to drop in 2006 following three years of decline, according to the report, which was based heavily on Chinese government statistics.

However, "(China) never committed to reaching those specific WHO standards within the timeframe of the Games,'' Falt said.

Beijing's Olympic organizers have said contingency measures, such as the selective banning of cars or temporarily closing factories, will have to be used to clear the skies -- pledges that were reiterated by officials Thursday.

Verbruggen and other IOC officials defended Beijing's efforts, saying organizers have spent more than the $12 billion they promised for pollution control but that growth has simply outpaced all predictions made when the city won the bid in 2001.

"As far as we're concerned, there is no blame to be addressed,'' Verbruggen told a news conference. "We all know that the development of this country and the development of this city has accelerated or enhanced the air quality problems.''

The UN report was generally positive about other environmental aspects of the preparations, praising the Beijing organizing committee's efforts in waste management, transportation and water treatment.

Solar power will be extensively used at venues and the Olympic village, and organizers have made an "extraordinary achievement'' in avoiding chemicals that damage the ozone layer, the report said.The International Olympic Committee on Thursday ruled out shifting events away from Beijing during next year's Olympics due to the city's foul air, though it and the United Nations cited pollution as a major concern.

With 10 months to go before next August's games, air pollution has emerged as one of Beijing's biggest problems in its generally smooth preparations.  The United Nations Environment Program criticized Beijing's progress on cleaning its air as slow and said some pollution exceeded World Health Organization standards.

In an overall positive assessment of Beijing's preparations, an IOC inspection team said air quality was a leading concern and that it was monitoring the situation day-to-day. The inspection team leader, Hein Verbruggen, said the impact of pollution on athletes' performance was a particular concern.

IOC president Jacques Rogge has warned in the past that the severe air pollution might force some outdoor endurance events to be delayed.

The IOC inspectors acknowledged some events might be rescheduled for a few days but expressed confidence that special measures would clear the air.

"The air quality is a big problem. You might wait a day or two but it is something that we're used to,'' Verbruggen told reporters. "It is a normal standard procedure that we have.''

The acknowledgment underscored the dwindling options organizers face as the Aug. 8-24 Olympics draw nearer.  Some countries are delaying their teams' arrivals in Beijing until the last possible moment to protect their athletes' performance.

China has one of the world's fastest-growing economies, but its cities are paying for it with choking pollution.  Beijing is often blanketed by a gray haze, some from coal-fired industries, others from the soaring numbers of cars.

"Extensive use of coal, the city's geographical location and a growing number of motor vehicles means the pace of improvement in Beijing's air quality is slow,'' Eric Falt, who heads the UN Environment Program's sports and environment project, told reporters at a separate event to release the agency's report card on Beijing's air.

Falt said small particulate matter -- fine particles of pollution that are harmful to human health -- were "particularly worrying.''

The UN report found that the average level of small particulate matter in Beijing's air in 2006 was eight times higher than the level recommended by the World Health Organization.

Other forms of air pollution -- sulfur dioxide, nitrogen dioxide and carbon monoxide -- rose or failed to drop in 2006 following three years of decline, according to the report, which was based heavily on Chinese government statistics.

However, "(China) never committed to reaching those specific WHO standards within the timeframe of the Games,'' Falt said.

Beijing's Olympic organizers have said contingency measures, such as the selective banning of cars or temporarily closing factories, will have to be used to clear the skies -- pledges that were reiterated by officials Thursday.

Verbruggen and other IOC officials defended Beijing's efforts, saying organizers have spent more than the $12 billion they promised for pollution control but that growth has simply outpaced all predictions made when the city won the bid in 2001.

"As far as we're concerned, there is no blame to be addressed,'' Verbruggen told a news conference. "We all know that the development of this country and the development of this city has accelerated or enhanced the air quality problems.''

The UN report was generally positive about other environmental aspects of the preparations, praising the Beijing organizing committee's efforts in waste management, transportation and water treatment.

Solar power will be extensively used at venues and the Olympic village, and organizers have made an "extraordinary achievement'' in avoiding chemicals that damage the ozone layer, the report said.