China will build a nation-wide network within three to five years to monitor the impact of air pollution on health, a latest step to deal with a persistent smog crisis in big cities, an official said.

　　A total of 43 monitoring spots will be set up in 16 provinces and municipalities frequently engulfed by smog so as to facilitate research on air pollutants in different regions, the impact on the health of vulnerable groups and the study of related diseases, said Xu Dongqun, an official with the Chinese Center for Disease Control and Prevention.

　　With funds allocated by the central government, the study will provide reference for preventive efforts to reduce the PM 2.5, Xu said.

　　Thick and hazardous smog have hit 17 provinces and municipalities with a population of 600 million this year. One of the major cities is Beijing, which has been shrouded in smog for several days during the ongoing seven-day national holiday.

　　China recently issued a 1.75 trillion-yuan (284.2 billion U.S. dollars) plan to tackle the worsening air, pledging to improve air quality within five years in order to decrease the number of heavily polluted days and improve the air in major city clusters.