China's environment watchdog on Wednesday started gauging public opinion on current air pollution monitoring standard and plans to implement a new and tighter air quality index.

Photo taken on Oct. 30, 2011 shows Beijing is enveloped by heavy fog. Heavy fog shrouds several northern and eastern Chinese regions Sunday. [Xinhua]

A website statement of the Ministry of Environmental Protection confirmed that the new standards will, for the first time, include readings of concentrations less than PM2.5 (particulate matters smaller than 2.5 micrometers), a major cause of haze harmful to health.

Tighter rules will also be set for some pollutants already monitored, such as nitrogen oxides and PM10 (particulate matters smaller than 10 micrometers).

The average yearly ceiling for PM2.5 concentrations is set at 35 micrograms per cubic meter while the limit for any one day is set at 75, according to the ministry.

The ministry plans to fully implement the new index standard nationwide in 2016, and the central government may designate certain regions to adapt to the new standard ahead of the national deadline and provincial-level governments could also decide to implement it earlier.

The World Health Organization's (WHO) air quality guidelines indicate that a yearly average reading of PM2.5 under 10 micrograms is deemed safe, while the daily average should not be higher than 25 micrograms.

But the WHO also published recommendations for developing countries to gradually improve their air quality regulations, and China's new standards are in line with those of the first-step targets, according to the ministry.

Major cities, such as Beijing, Shanghai and Guangzhou, have experienced chronic haze as a result of the surge in vehicle ownership and coal use in recent years.

During the past month, public pressure has been mounting for the government to strengthen monitoring and publish more accurate air quality evaluations.