Author: John Lee, Antonio Da Roza
Originally: June 2006
Air pollution is now regarded as one of the highest priorities in environmental protection in developing and developed economies worldwide.
The four criteria air pollutants used to estimate the impact of pollution on population health are respirable suspended particulates (RSP – measured as PM10 and PM2.5), nitrogen dioxide (NO2), sulphur dioxide (SO2) and the secondary pollutant ozone (O3) formed from nitrogen oxides and volatile organic compounds under the influence of ultra-violet light.
Reduction of Hong Kong air pollution to the levels in other world cities would avoid over 1,600 deaths and other benefits with a value of HK$19 billion annually. Air quality in HK is poor and compares unfavorably with other world class cities - particulate levels are about 40% higher than in Los Angeles, the most polluted city in USA.
Visibility is considered a good indicator of air pollution levels. The U.S. Environmental Protection Agency (EPA) identified reduced visibility as the best indicator of all environmental effects of air pollution. An analysis demonstrated that after adjustment for humidity and other factors, each one kilometre loss in visibility below 20 kilometres is associated with an increase in mortality risks of between 0.36% to 0.55%. On this basis between 1068 and 1650 deaths a year can be predicted by the loss of our horizon.
The July 1st 1990 restriction on sulphur in fuel oil which reduced fuel sulphur content to 0.5% by weight is associated with reductions in bronchitic symptoms in children and adults, improved lung function in primary school children, and a reduction in all cause mortality. Relatively small reductions in ambient air concentrations of pollutants lead to important health gains; the results of this Hong Kong intervention is now recognized world-wide as one of the most important pieces of evidence in the causal relationship between air pollutants and the injury to cardiopulmonary systems.
Since health impacts are a function of the concentrations at which pollutants are inhaled as well as the duration of exposures, transport presents the greatest exposure risk for some pollutants even if total emissions are higher from the power sector. Under typical urban conditions common in Hong Kong, the street canyon effect works to potentiate pollutant build-up during peak traffic periods. An estimated 50% of the population live and/or work in roadside environments.
Near term goals
- Rationalize bus routes to facilitate higher occupancy; ban pre-Euro and Euro I powered commercial vehicles on urban roads during peak periods; and provide better ventilation in the construction of under-story bus termini
- Implement regulations to monitor and restrict the tank contents of cross-boundary vehicles (as diesel fuel sulphur content in China is 40 times higher than in Hong Kong)
- The power sector the Hong Kong SAR government must act to expedite the siting of China Light and Power’s proposed liquefied natural gas facility.
Mid term goals
- Mandatory requirements for all diesel vehicles to move to Euro IV and Euro V standards should be implemented.
- Reduce transport services where there is excess capacity
- Turn mini-bus routes into feeder bus services to rail and long haul bus stations.
- Expedite the long overdue flue desulphurisation gas facility at Castle Peak; and there should be a moratorium on the use of sulphur-rich fuels in power generation on both sides of the boundary.
Long term goals
- The Government must act to make rail the backbone of the transport system.
- Buildings and redevelopment need to facilitate air circulation.
- In power generation, the Government must set a clear long term policy on whether the use of coal will be permitted, and under what circumstances in terms of sulphur and ash content and emission controls.
- The widespread use of bunker fuel and production of residual oil fly ash (ROFA) rich in metals is now one of the biggest threats to community health from air pollution but also the most easily prevented (manufacturing businesses operated by HK businesses).
- Hong Kong’s power companies should provide expert advice on plant operation and maintenance so as to improve efficiency and reduce emissions.
- Hong Kong must collaborate with Guangdong authorities to ensure that only clean diesel and petrol are available in the market, and that vehicles have the latest emission control technologies; HK should encourage Guangdong to implement high fuel and vehicle registration taxes.
- Provide high disincentives for use of a car on a regular basis during peak periods, including road pricing and higher car parking charges
- In September 2006 the World Health Organisation will promulgate the new Global Air Quality Guidelines (AQG), which have been agreed, on the basis of consensus, on the best evidence available from both observational and analytic studies of associations between air pollutant concentrations and a wide range of health outcomes.
- The general pattern shows that pollutant concentrations far exceed even the outdated Hong Kong objectives for PM10 and NO2. Even for SO2, the pollutant with the lowest levels relative to the new WHO AQG, the AQG were violated for 35% of the year.
- What is even more significant is the increasing annual trend in pollutants from sulphur rich fuels. Among these the most important may be the transition metals nickel and vanadium.
- http://www.civic-exchange.org/eng/upload/files/200606_AirPollutionSolution.pdf - last accessed 8/8/10