First, Hong Kong roads must be rid of polluting vehicles
Christine Loh sets out the priorities to clean up our dirty air, starting with taking the most polluting vehicles off our roads and retrofitting others to cut the harmful emissions that affect the health of thousands of people
Improving Hong Kong's air quality is a top priority because pollution affects public health. Measures must be strong enough to make a difference.
Most of our daily exposure to air pollution occurs at the roadside. In Hong Kong's dense urban areas, thousands of people are out and about every minute of every day. Many people work at the roadside or their place of business opens onto a busy road. And the windows of homes on the lower floors of a building open not far from these busy thoroughfares.
Moreover, our roads are relatively narrow, with tall buildings on either side. As a result, emissions from vehicle exhausts become trapped. The pollution in these "street canyons" cannot disperse easily, making it a daily health threat.
Hence, our near-term goal is to reduce roadside air pollution and our first targets are high-emission vehicles - diesel commercial vehicles (such as trucks, school buses and tourist coaches), franchised buses, LPG taxis and minibuses.
The most worrying roadside pollutant are the particulates - PM10 and PM2.5 (or particles that are 10 and 2.5 micrometres in diameter or less, respectively) - that arise from combustion in diesel engines. They can penetrate deeply into lung tissues, causing cardiopulmonary disease. The World Health Organisation recently confirmed that diesel particulates are also carcinogenic.
Our key solution deals with the 88,000 diesel vehicles in Hong Kong that do not meet the newer Euro IV emission standards. They make up about two-thirds of the total number of 128,000 diesel vehicles on our roads. Pre-Euro vehicles are now at least 18 years old, and emit 34 times more particulates than the Euro V models; even a Euro III vehicle emits five times more particulates.