Presentation on theme: "Impact of urbanization on the quality of air A case of HK."— Presentation transcript:
Impact of urbanization on the quality of air A case of HK
Air pollution issues street-level pollution smog
Common air pollutants in urban environment total and respirable suspended particulates (TSP & RSPs) sulphur dioxide (SO2) nitrogen dioxide (NO2) carbon monoxide (CO) ozone (O3) and photochemical oxidants (produced by ultra-violet light on nitrogen oxides lead (Pb)
How worse is the problem now? HK is one of the world’s 10 black spots regarding particulates. visibility has declined markedly since 1991. Poor visibility on dry and clear days is the result of smog, which is created when different pollutants combine under sunlight. Air Pollution Index recorded in many districts are far from satisfactory. In September 2002, roadside API reached a record level of 185 in Tung Chung. The air contains about the same amount of sulpur dioxide, nitrogen dioxide and ozone as that in London, New York, Boston and other major cities. in terms of carbon monoxide concentration, HK is rather low, far lower than Mexico City, Rome, Guangzhou, Los Angeles, London, Sydney, Berlin, New York, Toronto & Vancouver.
Air pollution sources (mobile) Road transport is the major source of street-level pollution and contributors to smog in urban areas. Most vehicles still use petrol or diesel. Vehicle exhaust gases contain respirable suspended particulates, hydrocarbons and nitrogen oxides (NOx). Smoke emissions from diesel vehicles are the main cause of high concentration of respirable suspended particulates (RSPs) and nitrogen oxides (NOx). (Conventional diesel vehicles emit about twice the NOx emitted by gasoline engines because of higher combustion temperatures.) Growth of cross-border transport in the past decade. More than 90% of the vehicles crossing the border are heavy diesel vehicles, generally poorly maintained and frequently overloaded. Also they use low grade diesel fuel thus increasing emission.
Air pollution sources (stationary) Power plants, gas producing plants, cement kilns and incinerators (all closed down before 1997) The two local power suppliers account for 89 per cent of our SO2 emissions and 45 per cent of NOx. The use of coal and fuel oil produces the most CO2 while natural gas produces the least.
Are power plants responsible for air pollution in HK? Emissions from power plants are considered under control because they are located far away from urban areas use of tall chimneys minimize their impact on nearby residential areas. from 1991, all new coal-fired electricity-generating units have been required to include the flue gas desulphurisation plants. This can reduce SO2 emission by more than 90%. Power plants have adopted de-NOx measures and low-NOx burners for their boilers. CLP Power Hong Kong Ltd. also has a cleaner-burning natural gas plant at Black Point. This greatly reduces the emission of SO2, NOx and dust particulates. However, recent instability in gas supplies has meant the company has to increase the use of coal
Industrial sources major pollutants emitted are SO2, NOx and unburned hydrocarbon due to the use of diesel fuel in their production process. Industry used the cheapest fuel for their boilers to maximize profits, it emits pollutants such as sulphur dioxide. In the 1980s, Kwun Tong and Kwai Chung are the 2 highly polluted ind. areas. The SO2levels recorded exceeded the AQOs (Air Quality Objectives) by 200%. In the 1990s emission from ind. sources have been reduced significantly. Now the SO2level is below the AQOs. Reasons: many HK factories relocate to Mainland China in late 1980s + strict measures adopted in 1990 to control fuel sulphur emission.
Other sources of pollution Open burning, continuous reclamation and construction projects created a serious problem of particulates suspended in the atmosphere Under the fast industrial development, our society produces lots of plastic and chemical rubbish. After the burning of useless rubbish, the rubbish not only cannot disappear, but also produces lots of harmful refuse. Open burning was carried out as an easy method to dispose of waste and unwanted materials.
Other sources of pollution Vehicles, industry and power plants in the Pearl River Delta create pollutants which spreads to HK by means of wind.
Causes of air pollution Vehicles, industry and power plants in HK and the Pearl River Delta area High population density and tall buildings make it difficult for polluted air to disperse. Weather In early winter, when weather is dry and there are calm conditions, particulates and other pollutants may not disperse easily so they tend to accumulate. The heat island effect can trap fine particulates and reduce visibility. Sunlight also intensifies the photochemical process between nitrogen oxides and hydrocarbons. The resultant chemical – ground level ozone – is hazardous to health.
Impacts of air pollution It causes discomfort and adverse health effects. High level of pollutant particles causes long-term health effects. Some visitors will shift their travel to other countries instead of Hong Kong due to the pollution & the destroyed landscape. For example, the visibility of Victoria Harbor decreases and it will badly affect the Hong Kong tourist industry. When there is serious pollution in Hong Kong, it’s difficult to attract the foreign investors to come to HK. This will badly affect our economy. Air pollution causes smog It leads to acid rain Ozone depletion is another result of pollution.
Solutions to air pollution Adopt strict diesel and vehicle emission standards use unleaded petrol. This will reduce lead concentrations in the air. use ultra-low sulphur diesel
Solutions to air pollution Reducing the absolute quantities of harmful gas emission By 2006, it will upgrade to Euro IV, the tightest standards available. pre-Euro light diesel vehicles have to set up particulate reduction devices. Also it makes particulate reduction devices a requirement for vehicle license renewal.
Solutions to air pollution Replacing vehicles with cleaner alternatives Diesel taxis to be replaced by LPG taxis (Liquefied Petroleum Gas) Nearly 80% of the public light buses are using LPG in 2004.
Solutions to air pollution Enforcement against smoky vehicles increase of penalty on smoky vehicles from $450 to $1000. Owners of smoky vehicles have to repair their vehicles and take them to the EPD for a smoke test. Failure to pass the test will result in the vehicle’s license being cancelled.
Solutions to air pollution promote better vehicle maintenance and eco-driving habits e.g. turn off the engines of cars while waiting along the road
Other measures control idling engines phasing out older and more polluting vehicles providing incentives for the introduction of environmentally cleaner vehicles restraining vehicle numbers and road use Some streets in busy areas (e.g. Mongkok, Causeway Bay) are "pedestrianized" at specified hours on everyday. By this process, it removes vehicles and provides the public a environment with better air quality. Trees are planted along side roads so to reduce the portion of carbon dioxide in air. Save energy – the government has set the air- conditioning temperature in all of its offices at 25.5 degrees Celsius
Tackling cross-boundary air pollution HK is affected by pollution and industries in the Pearl River Delta. Hong Kong and Guangdong are also co-operating on a joint programme to monitor air quality and share technical expertise. A monitoring network is almost ready to start operating. Sixteen stations are being set up - three run by the EPD, three by the Guangdong Environmental Protection Bureau and 10 by individual cities. The EPD provided technical assistance and training, drawing on its long experience in air quality monitoring. The government is also seeking to build up partnerships with HK companies operating in the Pearl River Delta region, to encourage them to control their pollution.
Long-term measures A Comprehensive Railway Strategy To improve air quality, it must be supported by a transport policy that places less reliance on motor vehicles. In HK, the MTR and KCR cause the least pollution as they are run on electricity. Car pooling is promoted. In the next 15 years, $220 billion will be spent on expanding the railway networks to bring 70% of homes and 80% of workplaces within one km. of a railway station. It aims to increase the traveling public from 31% to 45%
Long-term measures Development of alternative fuels – renewable energy Solar energy has the highest potential for widespread adoption in HK. Its main applications are found in heating, air conditioning and solar cell. Several local hotels in HK and the new abattoir in the New Territories have installed solar panels for water heating purposes. Reuse of landfill gases – the 1st landfill gas extraction plant was installed & operated in 1999 at the Sheung Wan Landfill site. Development of wind energy