本研究使用中央大學大氣物理研究所大氣化學模擬實驗室所研發的Windmodel模式，模擬2006年與2007年4月21日到5月20日質點擴散，探討春季台北地區空氣品質的特徵。 Windmodel模式為一個二維Langrangian模式，可針對台灣地區進行小區域的模擬，本文首先進行模式的敏感度測試，設計23個實驗測試模式中的時間步階，模擬及取樣時間，模擬區域，空間解析度，不同風場資料，質點釋放方式設定的敏感度。測試結果顯示模擬區域、風場資料和質點釋放方式的設定對模式的影響較大。 模擬2006年與2007年4月21日到5月20日，將模擬結果進行質點統計，計算以環保署空氣品質監測站古亭站為中心，半徑0.15度範圍內的質點總數，質點數與環保署空氣品質監測站的臭氧(O3)、一氧化碳(CO)、懸浮微粒(PM10和PM2.5)觀測值進行比較。質點統計的結果顯示在模擬的期間中顯示兩種不同的分布特徵，一種為單峰的高值，一種為持續的低質點數。比較觀測風場顯示單峰分佈和區域環流有關，此時台北地區的空氣污染受本地排放的空氣污染物影響。持續低質點數分佈時的風場為風速較強的東風，此時常受到來自大陸地區的空氣污染物長程傳送的影響。 Windmodel為一使用相當便利的工具，用Windmodel模擬藉由質點移動軌跡看出氣流的移動，由統計的質點數量變化可以簡單推測出此時的空氣污染是受本地排放影響或是推測是否會有傳送事件的發生。 Horizontal transport is a key factor in air pollution over Taiwan. This paper describes a two-dimensional Lagrangian particle controlling dispersion model, Windmodel, which has been developed by the Atmospheric Chemistry Modelling Lab, Institute of Atmospheric Physics, National Central University. Twenty-three experimentations have been designed for sensitivity test of the Windmodel. Twenty-three experimentations include time-step sensitivity test, simulation and sampling period sensitivity test, simulation region sensitivity test, spatial analysis sensitivity test, data of wind observation sensitivity test, and particle release sensitivity test. In this paper we present simulations with the Windmodel to study the characteristic of the air quality in Taipei area in spring season of April 21 to May 20 in 2006 and 2007, respectively. Amount of particles in the region which is fifteen kilometers around the Environmental Protection Administration Guting station are compared with the average of air quality observation. The results display two kinds of characteristic. One shows a daily peak pattern with a large number of particles, and the other one shows flat pattern with a few number of particles. The daily peak patterns are associate dwith local pollutant emissions in Taiwan, while the flat patterns are associated with long range transport from China.
