BEIJING - China's real estate tycoon Pan Shiyi on Sunday joined a growing group of media and public intellectuals to call for using tighter monitoring standards to rein in Beijing's notorious air pollution.

Pan, chairman of SOHO China, one of the largest developers in Beijing, initiated a public voting on his micro-blogging space at Sina Weibo to urge the authorities to use PM2.5, a widely used measurement to gauge finest particles in air, to check Beijing's air quality.

Beijing's meteorological authorities have been using PM10, which measures only coarser particles, to track the city's air pollution.

More than 33,000 people, about 95 percent of the voters who responded to Pan's initiative, agreed "the authorities would adopt PM2.5 measurement this year," four percent of the respondents believed "it can wait until next year" while only 1 percent opted for "there is no need for PM2.5 measurement."

On the other hand, the Beijing Municipal Environmental Protection Bureau (BMEPB) said in an official statement on Sunday that the capital's air quality has gradually been improving since the 2008 Beijing Olympic Games, according to the Beijing News.

The statement, which was released in response to mounting worries from the public of declining air quality, said Beijing had 63 days of excellent air quality in the past 10 months, 12 days more than that of the same period of 2008.

Additionally, the Air Pollutant Index (API), an indicator of the air quality, in 239 days so far this year had been below Level II, indicating good air quality.

The statement said dense fog that blanketed the city was to blame for nine days that failed to reach the national blue sky day standard in October. A similar situation occurred over the same period of 2008 and 2010, it added.

Du Shaozhong, deputy director of BMEPB, said last week the city is most vulnerable to heavy fog or haze at the turn of autumn to winter, but added he was optimistic the city's air quality would improve as the weather changed.

Du, however, admitted the city needs intensified efforts in emission reduction in order to improve air quality. He said the level of particulate matter had not met the national standards this year, as only 80 percent of the days passed the blue sky day standard through October 31.

The public debate on PM2.5 and PM10 first began when air quality monitoring results released by Beijing's weather forecast station and the US Embassy in Beijing often differed based on the different measurements.

While the results of the embassy described Beijing's air quality as "hazardous" or "dangerous," the Beijing weather forecast station said the pollution was only minor. Both sources defended their stances by saying that the difference was not manipulated but was the result of different measurements.

The debate intensified recently after the state broadcaster Central China Television (CCTV) aired a program hosted by popular commentator Bai Yansong calling for the adoption of PM2.5 measurement to track Beijing's air quality.

The program cited health experts as saying that fine particles are far more dangerous to human health and may cause cardiac and respiratory diseases as these smallest particles can be inhaled into the respiratory system while coarser particles are blocked through the nostril.

On November 1, the Ministry of Environmental Protection implemented a regulatory document in which it set the standard for measuring PM2.5 for the first time.

Experts say it is a worldwide trend to adopt PM2.5 measurement to check air quality and it is only a matter of time for Beijing to follow suit.

"Only when the state issues strong standards, the rules will be enforced by municipalities," Pan said. "And only when people have the knowledge of the air quality around them, will they change unhealthy behaviors."

Pan said he would wait a week to see the result of the voting and submit it to the Minister of Environmental Protection for policy consultation.