Abroad and at home, there is a rising chorus questioning the effectiveness of air pollution control in China, most recently from the thousands of runners who finished the Beijing Marathon in smog on Sunday. Still, officials and experts alike voiced their confidence about reining in air pollution, although they concede it will take time.

When about 30,000 runners from around the world came to Beijing for the event, some of them got cold feet due to the lingering smog. Runners with a variety of masks were caught in the media spotlight, raising questions about how long it will be before blue skies are back in our lives.

"It will take China about 20 to 30 years to tackle the problem of air pollution fundamentally, based on the experiences of developed countries like Japan, the United States and the UK in reining in air pollution," said Song Guangsheng, head of the National Indoor Environment Monitoring Center, at a forum on ecological cities on Monday, China National Radio reported on Tuesday.