2007年7月12日 看不见的风景
不幸的是,在香港,5月14日是个再平常不过的日子。游客们挤在香港最著名的观景点之一--山顶缆车(Peak Tram)终点站附近的太平山顶(Victoria Peak)观景台上,俯瞰这座浓雾笼罩的城市。 Unfortunately for Hong Kong, May 14 was an utterly ordinary day. Tourists milling at one of the territory's most famous lookout points - the Victoria Peak viewing terrace near the terminus of the Peak Tram - gazed down on a city bathed in heavy smog. A picture map, snapped on one of Hong Kong's rare clear days, depicted what they should have been able to see: the territory's famous harbour, now resembling a river after numerous land reclamations; the Tsim Sha Tsui peninsula; and the Kowloon hills beyond. But as tourists struggled to match the map to the view, only the harbour below and a few tall buildings in Tsim Sha Tsui could be made out through the haze. The Kowloon hills had disappeared completely. Turning their backs on the pollution, Chinese tourists posed for photos beside the picture map. And when they were finished, a French couple focused their camcorder on the image, as a proxy for the view they could not see. The invisible view has become increasingly commonplace in Hong Kong, which now experiences twice as much haze as it did a decade ago. Last year the city's observatory recorded 1,258 hours of reduced visibility, more than double the 581 hours of 1996. The severity of the haze is in large part determined by the conditions that historically made Hong Kong so ideal for the sea-faring trade. Reliable southerly winds from October to April provided easy passage for ships coming from the west and heading up the China coast towards Japan. From November to April a cold front blows in from the north, facilitating the return voyage. The sheltered harbour provided a favourable spot for rest and trade with China's interior. A hundred years ago the winter monsoons brought little more than a sprinkling of Gobi desert dust to Hong Kong. But today they bring much more from sources closer to home. Across the border, China's Pearl River delta region has crammed a century's worth of industrialisation into twenty years, transforming sleepy villages into 24-hour manufacturing zones. 香港最严重的污染可以追溯到佛山--一座距香港西北约150公里、拥有600万人口的城市。佛山被称作中国南部的陶瓷之都,在当地的空气质量图上,这座城市经常出现在最严重污染带的中心。在这里,烧煤的窑炉喷出大量的黑色废气及二氧化硫和二氧化氮等化合物。 The worst of Hong Kong's pollution can be traced to Foshan, a city of 6m about 150km northwest of Hong Kong. Known as the ceramics capital of south China, Foshan is often featured on regional air quality maps at the centre of the darkest circle of pollution. Its coal-burning kilns spew out huge quantities of sooty waste and chemical compounds such as sulfur dioxide and nitrogen dioxide. These pollutants are carried to Hong Kong by the northerlies that prevail from October to April, resulting in much worse pollution during the winter months. After the air stream reverses course in the spring and summer, reciprocal winds could be counted on to bring some respite from the winter haze. But this is no longer guaranteed, as the smog of May 14 showed. "In the past few years there has been a fundamental change- that is the probability of haze in the case of winds coming in from the northeast or southeast," said CY Lam, director of the Hong Kong Observatory. "We could see haze coming from clearly identified sources in western Taiwan. The particulate matter could come from many directions." Hong Kong's vehicles and coal-burning power plants also generate a fair share of pollution within the city, which is then exacerbated by local wind patterns and what is known as "land-sea breeze circulation". As concrete-clad urban areas heat up, pollutants rise and disperse over the ocean, only to be carried back into the city by cooler sea breezes. "When onshore wind comes it actually brings more polluted air instead of a very nice ocean breeze," says Alexis Lau, a professor and expert on atmospheric science at Hong Kong'sUniversity of Science and Technology. The problem is compounded by the rapid spread of cities across the Pearl River delta to accommodate a burgeoning population of 45m. "Increased heat due to urbanisation strengthens the land-sea breeze circulation and makes it more difficult for outside winds to penetrate, so it is more difficult for the pollution to dispers," says Mr Lau. Hong Kong's government has yet to develop a comprehensive solution to tackle the air quality issues that affect tourists and residents alike. Cross-border collaboration with the mainland has proceeded slowly, even though there are more than 50,000 Hong Kong-invested factories across the border. Five years ago, the two governments pledged emissions reductions by 2010 according to mainland China's air quality standards, which are in many cases more stringent than Hong Kong's. But it appears unlikely that the targets will be met on time. "If the reduction is actually happening we should be able to see the sky improving," said Mr Lau. "This is not the case yet." |