BEIJING, Aug. 8 (Xinhua) -- Beijing organizers assured the Olympic Games participants on Friday that the air quality is up to standard on the Olympic opening day.

    Recent foggy days raised some concerns over the Chinese capital's air quality which made Du Shaozhong, deputy director of Beijing Municipal Environmental Protection Bureau, once again sit before journalists from home and abroad.

    "It gives you a chance to know about Beijing's weather in summers. We have very diversified weather conditions, like sunny days, foggy days or rainy days," Du said in his opening remarks.

    Fog blanketed the city this week with little wind nor rain helping disperse it but the air quality is within the guidelines for safety levels, Du said.

    "Since July, especially from July 20, we have implemented temporary pollution control measures. So it is safe to say that today the pollution level is very much lower than before. Therefore improved air quality is a natural result," he said.

    Beijing pulled half of the 3.3 million vehicles off the road and as part of the pre-Games temporary measures which also include closing polluting factories in Beijing and some neighboring provinces, suspension of most urban construction projects, and removal of vehicles failing to meet emission standards.

    Du said in the past seven days the Air Pollutant Index (API), an indicator of the air quality, in Beijing has been all below Level II, indicating excellent or good air quality.

    "Maybe the fog makes it not a nice picture to look at the Bird's Nest or the Water Cube, but the monitor south of the two stadiums reads the API at 80 today. It conveyed a strong message that our efforts had paid off since August," he said. An API rating of 51-100 (level II) means good quality.

    The International Olympic Committee (IOC) chief medical official Arne Ljungqvist expressed his confidence in Beijing's air quality on Tuesday.

    "I'm confident the air quality will not prove to pose major problems to the athletes and to the visitors in Beijing," said the IOC medical commission chief.

    Chinese authorities have said they would take even more drastic measures if the "extremely bad weather conditions " happen, including removing another 200,000 vehicles from the road in Beijing and more than one million vehicles in neighboring provinces.