人工方法很难驱散雾霾

On days when the smog has been thick and choking, Beijing has been spraying streets with water to reduce dust and some people suggest to introduce artificial rain.

But according to Wang Yuesi, an expert in atmospheric physics with the Chinese Academy of Sciences, artificial methods can hardly reduce pollution.

"Artificial rain has nothing to do with smog reduction, because smog takes place in stable weather conditions. The problem is hard to change by artificial means. It is also not realistic to make wind because we cannot control where it blows. So source control is the only way to tackle the problem. Once the smog emerges, we can do little with it."

Wang Yuesi says to improve air quality, what we lack is not new technology, but rather strong enforcement of policies.

"If we apply desulfuration technology and dust elimination, coal pollution can be largely reduced. And if we use higher quality petrol with smoother traffic flow, car emissions can also be improved. We have mature technologies, but what is pivotal is forceful implementation and strict supervision."

But Han Difei, a researcher with Dalian Institute Chemical Physics, disagrees. He says we need more innovative technology and clean energy.

"So far, we don't have ultra-deep desulfurization technology in China. For example, Sinopec has introduced the technology from American giant ConocoPhillips, which has a monopoly in the Chinese market. It is urgently needed that we develop our own technology in this regard."

Experts also say it could take up to twenty years with persistent efforts to address the air pollution issue.

As part of the anti-pollution measures, some factories surrounding the capital have been forced to close temporarily, after the city issued an orange alert, the second-highest level.If officials ever announce a "red" alert, the top level, half of Beijing's cars are supposed to be taken off the road.

What's more, Chinese authorities have vowed to expand the scope of air quality monitoring and invest more in researching the health impact of smog.

For CRI, this is Li Jing.