Mobile source emission is one of the pollution sources that directly affects the air quality near the surface. The factor of estimation accuracy for mobile source emission includes vehicle age distribution, average mileage, fuel consumption, fuel efficiency, traffic flow and road length, the various control strategies are still difficult to characterize. In order to quantify the contribution of mobile source to air quality, it’s necessary to continuously improve the estimation for total amount of mobile source emissions, and combine it with the demand of quantifying emission reduction in terms of policy purpose.
The effectiveness of mobile source control and policy promotion can be understood through the assessment of emission reduction. This program reviewed and adjusted the suitability of each model parameters, which makes the model locally applied and reflects the effectiveness of policy promotion. In addition, the international strategies of public transportation control and low-emission vehicles promotion were also analyzed in this program. And was later developed in feasible plans to increase the use of low-emission transportation in Taiwan. Furthermore, negotiating with other ministries is also an important part of the work. The reduction of emissions from mobile source, involved in private transportation mode management, traffic control and public transport, it requires cross-departmental consultations and data integration to effectively clarify relevant policies among the various administrative units of the country.
In order to improve the effectiveness of controlling mobile source, this program keep tabs on various activity indicators and environmental load of mobile sources, interpret complex data into useful and easily understandable charts, and provide suggestions on the improvement of various mobile source controls to the Environmental Protection Administration, the results of this program are summarized as follows:
1. The mobile sources emission data were updated till 2020, including the activity of unit strength index, publication frequency, and historical data.
2. The results of emissions estimation in the past 2018 and 2019 were completed. And also completed preliminary results of emissions estimation in 2020 and 2021. The total emissions of 2019 were reduced by 1% ~6% compared with 2018.
3. The emissions of mobile-source vehicles have shown a downward trend year by year. The main contributors to the particulate pollutants TSP and PM2.5 emitted by exhaust gas are diesel trucks and diesel small trucks.
4. Complete the spatial and temporal weight distribution of emissions of various vehicle types in 2019, the PM2.5 and NOX emissions are mainly concentrated in metropolitan areas and expressways, the emissions of NMHC are mainly concentrated in urban area. From the point of view of time average weight distribution, the weights of expressways holidays for private cars and buses are higher than working days, and working days for interchange sections are higher than holidays.
5. The emission trend of mobile sources in the coming years, the emission factors will decrease as the old vehicles are replaced with new ones, from 2021 to 2041 years, there is a gradual downward trend. The concentration of vehicle exhaust particles has decreased 54-57%; NOX CO and HC have decreased by 64%, 35%, and 17%, respectively.
6. Completion of emission reduction strategy target and benefits evaluation. Through the year of 2020-2023, particulate pollutants can be reduced by about 5%, NOX can be reduced by about 5%, and NMHC can be reduced by about 3% annually.
7. Establish the energy consumption and emission parameters of domestic electric vehicles in the fuel life cycle. The well-to-pump (WTP-Fuel) and pump-to-wheel (PTW) life cycle account for 55% and 45% of vehicle energy consumption, respectively. The PM2.5 emission factor is 0.008～0.012 g/km, and the NOX emission factor is 0.310～0.453 g/km
8. Study the calculation formulas for reductions, including promoting the transfer of public transportations, increasing periodic inspection and inspection rate of scooters, and autonomous management of the fleet
9. In order to improve the efficiency of emission reduction in the electrification of buses, the priority of subsides should be given to electric buses running on high operating mileage and high-volume routes.
10. In order to reduce vehicle ownership and promote public transportation, the feasible action plan for promoting low-emission vehicle must still focus on old vehicle scrappage, taking insights from measures that was took across different departments, and consider energy efficiency oriented plan as future policy direction.
11. Encourage low-emission vehicle as a replacement for high-emitting vehicle, maintain incentives for car purchase subsidies to increase the replacement rate, establish complete infrastructure charging equipment to achieve low-emission vehicle pollution reduction benefits.
12. The traffic habits of Taiwanese were changed, during the Level 3 Alert period of the COVID-19 epidemic episode. The activity intensity of the mobile sources of various vehicle types changed and decreased, and the changes also affected the air pollutions concentration in the environment. In general, the activity intensity of vehicle reduction was leaded to improve air quality.
