China on Tuesday started to issue daily reports on air quality in 74 major Chinese cities by adopting more extensive monitoring standards, including the level of PM 2.5 - the smallest and most dangerous pollution particles.

Five other pollutants, including ozone and carbon monoxide, were also placed under the new monitoring standard issued in February by the Ministry of Environmental Protection.

The previous standard only covered PM 10 - particulate matter up to 10 micrometers in size, sulfur dioxide and nitrogen dioxide.

"I think monitoring PM 2.5 and publishing the concentration will increase people's awareness of environmental protection," said Pan Lei, a resident in Shanghai.

"But it is more important to take measures to reduce such pollutants in the air."

The data, released on the website of the China National Environmental Monitoring Center, are updated every hour.

People can also check the information for these pollutants monitored in the past 24 hours at various monitoring stations in the 74 cities.

PM 2.5 are considered more dangerous than larger particles, as they can penetrate deeper into the lungs.

High levels of PM 2.5 caused an estimated 8,572 premature deaths in Beijing, Shanghai, Guangzhou and Xi'an in 2012, according to a report by Greenpeace and Peking University's School of Public Health in December.

Some of the cities had already been releasing readings for PM 2.5. For example, Shanghai began to release figures for the concentration of PM 2.5 collected from 10 monitoring stations in June, while 35 monitoring stations in Beijing started to release the data in October.

Public attention focused on PM 2.5 in October 2011, when Beijing was shrouded in thick smog.

The US embassy in China's capital rated the air quality standard as "hazardous", while Beijing Municipal Environmental Protection Bureau said it was slight pollution.

It was later found the discrepancy resulted from two different air pollution monitoring standards adopted by the two countries, Xinhua News Agency reported, as China did not include PM 2.5 in the standard.

In May, the ministry told the 74 cities to apply a more comprehensive air quality monitoring standard and publish daily reports of PM 2.5.

Cities in major industrial areas, such as the Beijing-Tianjin-Hebei region, the Yangtze River Delta and Pearl River Delta regions, as well as all provincial capitals, were ordered to monitor PM 2.5 from October and publish readings before the end of 2012.

Beijing's air quality has improved for 14 consecutive years, with major pollutants falling in the city, Fang Li, spokesman for the municipal environmental protection bureau, told a news conference at the end of last year.

The annual average concentration of major pollutants, including nitrogen dioxide and PM 10, fell by 4 percent in 2012, compared to the previous year, he said.

wangxiaodong@chinadaily.com.cn

(China Daily 01/02/2013 page2)