The total number of registered motor vehicles in Taipei City is 1.8 million including a total number of 1 million registered motorcycles, resulting in a vehicle density of 6633/km2. Apart from the vehicles already in the city, about 250,000 vehicles commute to Taipei City from other cities each day. Motor vehicles are therefore the main air pollution source in Taipei City, producing 57 percent of air pollutants and 33 percent of greenhouse gas emissions.
In order to reduce air pollution and create a low-carbon city, Taipei set up public dynamometers to measure the emissions from diesel vehicles and control PM2.5 emissions from diesel buses and trucks in the city. By awarding “low-pollution identification symbols” to diesel vehicles, Taipei reduced the pollution emissions from diesel vehicles, thereby improving air quality and public health. By the end of 2013, there were 4436 diesel buses and 936 diesel trucks with the low-pollution symbol. It is anticipated that with this program, up to 104.7 tons PM2.5 emissions can be reduced per year.
The “YouBike” project began in 2009 to further combat the effects that motor vehicles have on the city’s air quality by introducing a bike sharing option for commuters. The YouBike service is available throughout the city and provides a convenient option for users to avoid driving and public transport. In 2009, 500 bicycles were made available at 11 rental stations. Today, there are 160 rental stations and 5265 bicycles. The number of YouBike users has already reached 1.9 million , while the total number of usage is over 20 million, and has gained popularity as the first 30 minutes of use is free.
The goal of both projects is to increase use of public transport and thereby improve air quality. In 2013, the daily traffic volume of MRT (Taipei Metro) and bus system already exceeded 3.3 million, representing a growth of 22.4 percent from 2003.
There are three main objectives of Taipei’s air quality improvement plan, namely Cleaner Air, Healthier Environment, and Better Services. To achieve these goals, the city has set several long term goals: