Hong Kong continues to battle smog almost every day. Blue skies are becoming the exception rather than the rule as vehicles belch exhaust fumes and coal-fired power plants add to the misery. Hongkongers are regularly subjected to unhealthy levels of respirable suspended particles (RSPs), nitrogen dioxide and sulphur dioxide. Environmentalists have criticised the city's Air Pollution Index for being outdated and for failing to measure the seriousness of the problem. Recent research by the University of Hong Kong has found that the air contains twice as much soot and other pollutants as London and three times as much as New York. Chief executive Donald Tsang Yam-kuen has pledged to 'fix' Hong Kong's unacceptable air quality, which has been cited as a factor in hurting the city's long-term competitiveness. Newspapers have reported that the government's goal is to reduce four major pollutants by 55 per cent by 2010. At Eco Expo Asia, air quality is one of the four themes of the fair and the subject of a panel at the Eco Asia Conference. Yeung King-lun, associate professor of the department of chemical and biomolecular engineering at Hong Kong University of Science and Technology (HKUST), will discuss indoor air pollution. 'Indoor air is always worse than outdoor air. Air-conditioning doesn't filter our air pollutants. All it does is cool the air,' Professor Yeung said. Compounding the problem indoors was the fact that formaldehyde might be released from furniture and carpeting, he added. With indoor air pollution, sufferers can experience headaches, allergic reactions and stuffy noses. Air purifiers are often used in an attempt to clean indoor air, but Professor Yeung said that many of these were of limited value. Older models simply removed dust particles. 'They cannot remove RSPs and pollutants,' he said. Some newer models may also remove unpleasant odours. In recent years, Dr Yeung has spearheaded a successful effort at HKUST to create a more effective air purifier through the use of nanotechnology, which deals with materials on an atomic or molecular level. His team has created an air purifier that can remove harmful pollutants, such as volatile organic compounds, sulphur dioxide and carbon monoxide, in addition to dust particles and odours. The device converts the pollutants into harmless substances. 'It's an improvement on existing air purifiers. We can treat some of the pollutants that other purifiers cannot treat,' he said. The unit was expected to be on the market in the next year or two and would sell for about US$100, he said. Another topic the air quality panel will discuss is a WWF Hong Kong project aimed at reducing the greenhouse gases produced by factories in the Pearl River Delta. Greenhouse gases, trapped in the atmosphere, are causing the global warming effect, which is melting the polar caps, raising sea levels and playing havoc with the climate. These gases include carbon dioxide, methane, nitrous oxide, hydrofluorocarbons, perfluorocarbons and sulphur hexafluoride. Although these gases occur naturally in the environment, emissions from vehicles, electricity generation and industry can artificially increase their levels. '[Through the WWF project] manufacturers will be provided with tools to measure and monitor their carbon footprint, and to identify gaps against best practice energy management systems and technology processes,' said conference speaker Karen Ho, business engagement leader, climate, for WWF Hong Kong. A toolkit consisting of a management best practise handbook and carbon accounting software for the WWF project is also being developed with the Hong Kong Productivity Council and renewable energy company Ecofys Azure. The programme is sponsored by the Bowen Asia Green Dragon Fund Award. First to be targeted would be manufacturers in the electronics, plastics and textile and apparel industries, Ms Ho said. Manufacturers could reduce their carbon emissions by 'retrofitting equipment to become more energy efficient, and reducing overall electricity consumption and using cleaner fuel', Ms Ho added. Besides reducing carbon emissions, she said that the project would also help reduce air pollution.