"The technologies involved in the manufacturing industry also need to be improved," said Su. "For example, Japan has the world's lowest level of emissions per unit of output value. If China could also achieve that, a lot of emissions could be reduced."

Forecasts, warnings

Wang Yuesi, a researcher in atmospheric physics at the Chinese Academy of Sciences, said airborne pollutants in Beijing caused by sources from outside the capital account for about one-third of the city's pollution.

Judged by types of source, motor vehicles produce approximately 50 percent of the city's air pollution.

Severe haze and smog covering the Bird's Nest on Wednesday. Wei Xiaohao / China Daily

Wang said if the public wants change in the short term, all it can count on is the development of the weather forecast and warning systems.

"For example, if the forecast shows that we are expecting smog and haze in the week to come, we can take preventive measures such as regulating the use of motor vehicles, or halting production and foundation work in factories and construction sites for several days ahead of it," said Wang. "After all, pollution as severe as last week's is unlikely to occur more than three times in a year, and thus can be dealt with by implementing short-term controls if the warnings are given in time."

In an ideal world, the warnings would be issued five to seven days in advance, so that the relevant departments have enough time to prepare, he said.

"We now possess the technology to make such a forecast, with accuracy of about 50 to 60 percent, which is pretty high," said Wang. "Also, scientists should only be responsible for informing the government about the possibility of bad weather. The authorities need to have the final say on whether emergency plans need to be implemented because they usually incur sizable economic losses."

As for the control of private cars, Wang didn't agree with making it a permanent regulation, but said the government can let the public know about the situation and suggest appropriate action.

"For example, the government can inform the public that the weather in the following days will make it hard for pollutants to diffuse, and then call on people to use public transport. By promoting the measures gradually, we can avoid public resentment on this issue."

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