Wang Gengchen, a researcher at the Chinese Academy of Sciences' Institute of Atmospheric Physics, is also worried about the negative effect of inaccurate weather forecasting.

He said that as the forecast will lead not only to some vehicles being barred from the roads, but also affect industrial production, classes for students and close construction sites, the forecast must be accurate and delivered on time.

Qiao said the bureau will improve its forecasting ability to reduce the chances of inaccurate predictions and warnings.

The meteorological department gives daily updates on Sina Weibo, the Chinese equivalent of Twitter, on the weather conditions affecting the spread of pollution.

In addition to the concerns voiced by experts, some members of the public are not optimistic about the effect of the traffic control measures.

"It is fine to introduce the odd-and-even license plate rule, but I don't think it really helps," said Lu Wei, a 45-year-old private trading company owner.

"The rule may slightly ease pollution pressure for a while, but as long as the number of private cars on the roads rises and cars with excessive emissions are not prohibited, such a rule might not have any effect."

Lu said it is important to curb other major sources of pollution, such as the cement and steel industries, rather than disturb people's daily lives.

Lu Guangtian, 26, a bank clerk in Beijing, said that if vehicles are restricted on days of heavy pollution according to their license plate numbers, the government should offer compensation to the owners.

"It is unfair if you have just bought a car and are forbidden from driving it on the roads," he said.

But Sun Changliang, a 43-year-old engineer, said, "It's worthwhile having a breath of fresh air in exchange for not being able to drive for a day."