About 5,000 metric tons of tiny poisonous particulates (called PM2.5) are emitted annually into Hong Kong's air. Thousands of people, particularly the elderly, are dying every year from inhaling the city's dirty air.

A 13-year study by researchers at the University of Birmingham and the University of Hong Kong has found that air pollution does not only cause lung cancer. In fact, it causes all kinds of cancers - from breast to pancreatic cancer. This new finding is very worrying. In addition, a local newspaper report on May 9 stated that according to a government-funded Cancer Registry prediction, the number of Hong Kong people affected by cancer in 2025 is expected to increase 30 percent to about 35,000 from the figure in 2012.

What the Hong Kong government should do now is tightening up regulations on air pollution. Citizens should demand the government do so. The World Health Organization (WHO) stipulates 25 micrograms of PM2.5 particulates per cubic meter as the acceptable limit for 24-hour particulate concentrations and 10 for annual particulate concentrations. However, our city's limits are less stringent, at 75 and 35, respectively. So, our air pollution limits are three times more lenient (or more poisonous) than world standards. These limits should be tightened up immediately.

There can be no room for complacency. It is time we toughened our air-pollution limits and brought them more in line with the WHO's. Too many lenient policies only help to kill more people, the elderly in particular, in the city. When people's lives are at stake, we should take some inspiration from the WHO and hesitate no more.

Air pollution is mainly caused by cars on city roads and vessels in Victoria Harbour. The Hong Kong government should have the courage to tackle these two main sources of pollution. Marine transportation vessels, such as the cross-harbor ferries, should be urged to use more environmentally friendly fuels. Cleaner fuels would contribute to cleaner air.

The government should also take steps to cut down on the number of cars in Hong Kong and encourage drivers to take public transport. Immediate measures could include installing electronic pricing systems in busy areas such as Central, Causeway Bay and Mong Kok to discourage people from driving. Some upper-and middle-class people might be irked by these new measures. Nonetheless, the government should have the majority's interests at heart and shouldn't be afraid to displease the rich and famous in Hong Kong. Chief Executive Leung Chun-ying should end the myth that our city is run by the rich and famous, not by the Hong Kong government.

Also, a warning system should be broadcast through radio and TV stations, and perhaps inside MTR trains, to caution citizens to avoid going into polluted districts. Such a policy could minimize the number of people exposed to harmful particulates. Saving people's lives can also mean less expenditure on hospital beds, thus helping Hong Kong's finances.

Another measure the government could take is to limit building projects in busy districts such as Causeway Bay and Mong Kok to allow better air flow. Developers should be encouraged to launch new residential projects in remote areas in the New Territories. Another measure is to set up more pedestrian-only streets and districts to limit vehicle traffic, and hence reduce air pollution. This would save lives.

The latest study by the two British and Hong Kong universities should serve as a warning sign that more local people are being killed by air pollution in the city, particularly the elderly. The Hong Kong government should not bury its head in the sand. It is time the government took actions to reduce pollution in the air.

(HK Edition 05/12/2016 page8)