| Summary: | 碩士 === 國立嘉義大學 === 史地學系研究所 === 100 === The objective of this paper is to examine the weekend effect, defined as the difference in concentrations of air pollutants between weekends and weekdays, in six regions of Taiwan – North, Tao-Chu-Miao, Central, Yun-Chia-Nan, Kao-Ping and Yi-Hua-Tung. Surface measurements of 54 monitoring stations from the Environmental Protection Administration during 1994-2010 are analyzed.
Except NO2+O3 in the Yi-Hua-Dong area, daily mean concentrations of air pollutants are all found with the weekend effects over the main island of Taiwan. The air pollutants including NOX, CO, NMHC, O3, SO2, PM10, NO2, NO and NO2+O3 are lower on weekends than on weekdays except O3. Nonlinear photochemistry and titration effect generate more ozone on weekends than on weekdays.
Seasonal mean concentrations of the air pollutants are most found with the weekend effects except CO, O3, PM10, NO2+O3 and UV-B in some seasons. Weekend effects of pollutants for astronomical seasons are strongest in spring and weakest in summer and those for natural seasons are strongest in spring rainfall season and weakest in typhoon season. Weekend effects of air pollutants are found more in astronomical seasons than in natural seasons.
Weekend effects of NMHC and O3 in the North area and those of NOx, CO and NO2 in the Kao-Ping area show an increasing trend. Weekend effects of SO2 and PM10 in the North area, those of SO2 in the Tao-Chu-Miao and Central areas, and those of NMHC and SO2 in the Yun-Chia-Nan area have a decreasing trend. However, weekend effects of other pollutants in six regions do not show a significant trend.
Weekend effects of air pollutants of NOx, NMHC, NO2 ,NO and NO2+O3 are higher in the North area, and those of CO are higher in Central and Yi-Hua-Tung areas, those of O3 and SO2 are higher in Tao-Chu-Miao area, that of PM10 is higher in Kao-Ping area, and those of most air pollutants are lower in the Yi-Hua-Dong area. This implies a distinct difference in weekend effects of air pollutants between the rural and urban areas. Moreover, weekend effects of NOx, NO2, NO and NO2+O3 are related to population and motor vehicle numbers, that of CO is related to population number density and that of NMHC is related to population number. Weekend effect of PM10 is related to rainfall, and those of NOx, CO and NO2 are related to wind speed.
The NMHC/NOx ratios in North, Tao-Chu-Miao, Central, Yun-Chia-Nan areas are found with weekend effects, higher on weekdays than on weekends. The associated ozone photochemical reaction and control policy are also studied.
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