Beijingers will need their masks. There are no more 'clean air' days

The imminent arrival of winter in Beijing doesn't just ensure minus 10C temperatures and a bitter wind that roars in from Siberia via Mongolia. It means one of the world's most polluted cities will become even more dangerous for its residents as the thousands of coal-fired furnaces that heat the city's apartment blocks, as well as thousands more coal-burning domestic stoves, start sending sulphur dioxide into an atmosphere already filthy from the pollutants spewed out by hundreds of factories and millions of car exhausts.

As China grows by leaps and bounds, the ugly-side effects of Chinese-style socialism, as economic development is euphemistically called, are on constant view in the capital. Each year, Beijing's Municipal Environment Protection Bureau sets a target of clean air days, 227 last year, and each year the city fails to achieve its goal. For Beijingers, that means that not only are the Fragrant Hills on the western outskirts of the city often obscured by a foul, grey pollution haze, but it can be difficult to make out buildings a few hundred yards away. On the worst days, you can taste the pollution in your mouth and asthma sufferers and those at risk from respiratory diseases are told to stay inside.

Last week, the Bureau acknowledged that pollution will only get worse. "Looking at the changing trend in Beijing's weather over the past few winters, the situation isn't very promising," said Du Shaozhong, the vice-director of the Bureau. There have been 190 clean air days in Beijing this year, but the arrival of winter means there won't be many more. An emergency plan will go into effect if, as expected, there is heavy air pollution for two consecutive days. Factories with high levels of emissions will be ordered to cut production, street cleaners will deploy and trucks will trundle through the streets spraying water to damp down the dust that swirls through the air on a daily basis.

But it's the trucks with dodgy exhausts that help make Beijing such a polluted place. Along with the 2.5 million cars, a number increasing by a 1,000 a day as the middle classes turn their backs on bicycles and a public transport system that covers just a fraction of the city, it means many days when Beijingers wear masks.

Nowhere is more polluted than the Shijingshan district in western Beijing. Home to the Shougang Group, China's largest steel makers, it's a wasteland of heavy industry and chemical factories with tall chimneys belching black smoke. Shougang's vast steel and iron smelters discharge some 18,000 tons of particle matter every year, while waste water from the plants gets pumped into Beijing's canals.

Winning the right to host the 2008 Olympics was supposed to spur Beijing into tackling its pollution problem. But construction on the venues, along with a building boom that means there are 6,000-odd construction sites in Beijing, has only exacerbated the situation. There's so much dust that no one leaves their windows open.

But, unlike in Shanghai, car tax hasn't been increased. Nor is enough heavy industry being re-located outside the city to make a significant difference to the pollution problem. Beijingers will need their face masks for a while yet.