Zhong Nanshan attends a penal discussion at the fifth session of the 11th National People's Congress (NPC), at Beijing Capital Hotel, March 7, 2012. [Photo/IC]

Expert: Effects of smog on lung cancer as yet unproven

Zhong Nanshan, National People's Congress (NPC) delegate and a respiratory expert, said there is a lack of evidence to link smog and lung cancer. However, nitrogen dioxide, a major pollutant in smog, is closely linked to a high lung cancer rate.

Air quality became a hot topic before the parliamentary sessions as a documentary on pollution by former TV anchore, Chai Jing, chalked up 136 million views in two days.