The Guangdong provincial environmental protection agency is working on a system to better evaluate its air quality.

The new system will include indices on visibility, particle mass concentration of PM10 (particles with a diameter of less than 10 microns), and black carbon particles, Nanfang Metropolis Daily reported on Thursday.

"The present air quality evaluation system was devised 20 years ago. It only includes indices on sulfur dioxide, nitrogen dioxide, and inhalable particle matters of PM10," Liu Guoxian, an official with the provincial environmental agency, said.

"The new system will be better able to evaluate haze, which has long plagued the province, especially the Pearl River Delta region.

"PM10 and black carbon particles are the main cause of haze," Liu said.

He could not give a definite date when the new system will be put into effect.

The Pearl River Delta cities of Dongguan, Foshan, Shenzhen, Guangzhou and Zhaoqing experienced haze for more than 100 days last year. Dongguan, in fact, had 213 hazy days.

"Guangdong is currently capable of monitoring haze, but an updated system will benefit research and lead to improvement of the air quality in the Pearl River Delta region," Wu Dui, chief of the Guangzhou Institute of Tropical and Marine Meteorology, China Meteorological Administration, said.

"For the Pearl River Delta region, indices on visibility and PM10 are more crucial than any other indices. PM10 is one to three times more serious here compared to the developed countries.

"Excessive emission of black carbon particles due to vehicle emissions is also to blame for the worsening visibility," Wu said.

(China Daily October 10, 2008)