As diesel engine has high output horsepower, it consumes relatively less fuel comparing with petrol engine. This is has resulted in the wide applications thereof, including passenger/ freight transportation, military or construction machinery. Nevertheless, research indicates that the black smoke emitted by diesel vehicles can cause serious harm to human body. This is the reason that, with respect to vehicle pollution controls, not only are new vehicles examined with stricter standards, but regular maintenance and inspections are highly promoted to enhance the air quality.
According to the results of air quality model analysis carried out by Environmental Protection Administration, Executive Yuan, apart from pollutants coming from overseas, the impacts of mobile source, industrial source and other fixed source pollutions to the concentration of fine suspended particles (PM2.5) are 30% to 37％, 27% to 31％ and 32％ to 43%, respectively. Among them, the proportion of diesel truck reaches around 11.2%~16.8%, making it in the No. 1 pollution source. According to TEDS (Taiwan Emission Data System) 11.0, Chiayi City’s total PM2.5 emission is about 226.28 t/yr. Among them, the PM2.5 emission of mobile source is around 108.54 t/yr, counting 48.0% of the total amount; and, among all mobile sources, the PM2.5 emission of diesel vehicle is 42.15 t/yr, counting 38.84% of total mobile source pollution.
To effectively control Chiayi City’s diesel vehicle air pollution, several control measures, including roadside inspection/visual audit, diesel vehicle self-management program and school bus/official state vehicle controls, have been implemented. The purposes thereof are to find high-polluting vehicles through audits and controls to further reduce the pollution; and to, with the license plate recognition system, find unidentified polluting diesel vehicles and inform the owners thereof to take an inspection.
The said measures can facilitate our understanding in smoke pollution created by diesel vehicles driving in the jurisdictions of Chiayi City; and encourage heavy-duty diesel vehicle owners to replace the old vehicles, regularly maintain and repair vehicles, install air-pollution prevention and control equipment and assist the owners in applying for subsidy. Through this integrated approach of audit, promotion and subsidy, controls on diesel vehicles will be strengthened; and owners will be reminded to enhance regular vehicle maintenance works to ensure the diesel vehicle’s compliance with emission standards. All of these can enhance environmental air quality and reach the objective of having a clean environment. Apart therefrom, the government also implemented a number of measures, including: promote “park and stop” for idling vehicles and carry out audit works in administrative areas where idling often occurs; implement on-site noise detection works; and cooperate with the Police Bureau, Motor Vehicle Office and Environmental Protection Bureau to conduct night audits, helping to minimize noises caused by motor vehicles and return tranquility to all citizens.
The performance results of the plan starting from February 20, 2021 to December 15, 2021 are as follows:
1. 2,316 diesel vehicles were inspected at the station and 45 vehicles failed. The failure rate thereof was 1.9% and 2,286 vehicles were issued with the diesel vehicle self-management certification mark.
2. Selected 797 vehicles and inspected 161 of them (82.0% of them are Phases I to III diesel vehicles) at roadside. 79 vehicles failed and the failure rate was 49.1%.
3. 208 diesel vehicles were visually identified and notified accordingly
4. Implemented road license plate recognition and successfully identified 562,478 diesel vehicles and proactive inspection notices were sent to the owners of 2,012 vehicles
5. 1,005 vehicles were inspected to park and stop.
Upon establishment of Clean Air Promotion Committee, Chiayi City Government has committed to minimize air pollution impacts on citizens’ health. Among all air pollution mobile sources, exhaust gas emitted by diesel vehicles is the one that has been most criticized by the public.
Through various audit and promotion measures, this plan forces diesel vehicles entering and leaving the jurisdictions to take and pass the inspection and further acquire the self-management certification mark. The purpose thereof is to ensure that all diesel vehicles entering and leaving Chiayi City comply with the exhaust emission standards in order to effectively reduce the City’s pollution source. Currently, only 93.7% of diesel vehicles inspected at an exhaust inspection station pass the test and 97.2% of them have obtained the self-management certification mark. Having all diesel vehicle obtained a certification market still requires great effort. This year, the city government has targeted the old and high-polluting Phase I, II and II diesel vehicles as the primary audit targets, plus the implementation of Environmental Protection Administration’s heavy-duty diesel vehicle replacement subsidy, fuel injection system repair subsidy and air-pollution prevention and control equipment installation subsidy to reduce the air pollution source. Upon implementation of the plan until now, only the replacement of diesel vehicle can permanently reduce the pollution source. To effectively reach the objectives of pollution reduction, it still a must to continuously promote regular inspections on diesel vehicles to ensure their compliance with exhaust emission standards. Upon implementation thereof, this plan has succeeded in reducing 14.50 t of PM10, 12.90 t of PM2.5, 191.17 t of NOx, 17.25 t of NMHC and 66.95 t of CO.