Lanzhou was the city with the worst air pollution while Haikou had the best air quality in the country, according to an air pollution report conducted recently in about 1,100 cities in 91 nations by the World Health Organization (WHO).
The report revealed the average annual PM10 (particulate matter smaller than 10 microns) level, an air quality representation index, in Lanzhou, Northwest China's Gansu Province, was 150 μg/m3 (microgram per cubic meter), 130 μg/m3 more than the recommended healthy index of the WHO.
The index in Xining in Qinghai reached 141 μg/m3 and Urumqi in Xinjiang Uyghur Autonomous Region came in at 140 μg/m3, ranking the second and third worst for air pollution.
Comparatively, the index in Haikou of Hainan was 38 μg/m3, becoming the least polluted city followed by Lhasa in Tibet Autonomous Region and Nanning in Guangxi Zhuang Autonomous Region with both standing at 50 μg/m3.
"An overwhelming amount of thermal power stations and the exhaust gas yielded from coal-burning stoves, often used by residents in Lanzhou, Urumqi and Xining in winter to keep warm, were the major causes of the polluted air," Sun Qingwei, an expert in air pollution from Greenpeace, told the Global Times on Wednesday.
"Lack of sufficient ventilation due to the valleys there also aggravated air contamination," he said, adding that the frequent sandstorms there play a role as well.
The WHO said nearly 2 million people die annually from breathing in the solid particles suspended in both indoor and outdoor air, which might cause heart disease or lung cancer.
The report also showed the index in Beijing was 121 μg/m3 and Shanghai reached 81 μg/m3.
The PM10 index in Washington DC was only 18 μg/m3 while Tokyo and Paris was 23 μg/m3 and 38 μg/m3, according to the report.
"The remarkable disparity between the big powers and China reminds us of the chasm in environmental protection, urging us to set up a scientific development-oriented target rather than taking the GDP as the sole aim in boosting the nation's strength," Sun said.
He suggested citizens resort to more green transportation means when going out and develop more contaminate-free energies as alternatives.