The share of hazy days throughout 2010 for eight Chinese cities under a pilot program for haze monitoring stood between 20.5 percent to 52.3 percent, according to results released Tuesday by the China National Environmental Monitoring Center (CNEMC).

China began monitoring haze in 2008 in eight pilot cities, including Tianjin, Shanghai, Chongqing, Shenzhen, Guangzhou, Suzhou, Ningbo and Nanjing.

According to the 2010 results, the number of days when PM 2.5, the measure of microscopic airborne particles, exceeded the safe level in these cities accounted for 1.9 percent to 48.9 percent of the total monitoring days.

In general, the PM 2.5 pollution in these pilot cities is serious, said Luo Yi, president of CNEMC, during an interview Tuesday on the sidelines of the National Environmental Protection Conference.

Luo proposed that PM 2.5 monitoring be implemented in all densely-populated regions and severely-polluted regions by 2013, earlier than the previously proposed deadline of 2016.

The government recently proposed to include "PM 2.5" into its pollution monitoring system nationwide.

The plan to measure finer matter -- considered more hazardous to people's health, as it can penetrate deeper into the lungs -- is scheduled to be fully implemented nationwide in 2016.

Luo said the nation-wide implementation of PM 2.5 monitoring takes time, as it involves purchasing and installing a vast number of instruments, refining data quality control and training personnel.

China currently uses PM 10, which gauges particular matter under 10 micrometers, to measure air quality.