| Summary: | 碩士 === 逢甲大學 === 環境工程與科學所 === 98 === Nantou County is famous for her many wonderful sceneries in Taiwan. After NO.6 freeway was constructed in Nantou in 2009. There were a lot of sightseeing tourists crowed into Nantou County for better traffic condition. However, it bring forth the impact on environmental pollution at same time. This study is to evaluate the change of traffic-patterns due to the construction of the NO.6 freeway and their impact on air quality, the health risk and potential risk area and modified using CALINE4 model. Various case of weekdays,weekends, and multiple-day holidays were studied.
The result show that, the Total Traffic Index (TTI) value in weekdays,weekends, and multiple-day holidays in and out of Nantou County were larger than 1, revealed that the NO.6 freeway did attract a large number of vehicles on weekend and holidays. And the Vacation Traffic Index (VTI) value before and after the construction of NO.6 freeway were larger than 1, showed that there were more vehicles on both weekends and multiple-day holidays than that in weekdays. More signification condition was found after the NO.6 freeway was constructed.
As for the Taichung-Sun Moon Lake Highway (NO.14 provincial highway) the TTI value were obviously less than 1, especially on multiple-day holidays, meant that traffic on NO.14 highway was significally reduced owing to the construction of NO.6 freeway, but if the traffic for both NO.14 highway and NO.6 freeway were considered altogether, the TTI value were larger than 1, especially on weekends, meant that though traffic on NO.14 highway was decreased , the total traffic on NO.14 with NO.6 freeway were actually increased. It also revealed that the short-term traveling is in vogue.
For the original packaged CALINE4 model was accessible only for 20 links, 20 receptors and height under 10 meters. These limitations were removed in the modified model in the work.
Examination for the modified model with original packaged CALINE4 model under various conditions were proceeded and found identical results. When compared with field measurement, the modified model proved to be more precision than the original CALINE4 model for the high elevated freeway.
According to the numerical simulations, the highest concentraction were reduced in Nantou County after the construction of NO.6 freeway. For air pollutant CO in the four sensitive regions (N-S traffic line region, East Caotun, Guoshing and Puli regions), the Air Pollution Assessment Index (APAI) values were less than 1 on weekdays, weekends, and multiple-day holidays. The air quality improved in those regions.
Risk assessment in four sensitive regions were proceeded. The HQ (Hazard Quotient) values were all less than 1, meant that it will not bring about Cardiovascular system to the human body. On the other hand, the RAI (Potential Risk Area Index) were utilized to assess the potential area of air pollutant. The RAI value due to the traffic pattern change showed positive except some low potential regions.The RAI value due to both the traffic pattern change and emissions coefficient change showed significant improvement, it showed that though heavy traffic was introduced, the potential area was on the contrary minimized due to better driving conditions, especially on weekends and multiple-day holidays.
Keyword:NO.6 freeway, CALINE4, Traffic-line pattern, air quality, Risk assessment, Potential risk area index, Nantou county
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