應用CALPUFF模式於複雜地形與建築物效應之研究

Abstract

為了瞭解複雜地形效應以及建築物效應的影響，同時使用ISC模式與CALPUFF模式來模擬。將兩種效應結合不同大氣穩定度與混合層高度，得到不同情況下的最大濃度值以及濃度分佈的型態。 首先，先比較兩種空氣品質模式的基礎，來瞭解其差異性。兩模式在風場表現時便極為不同。在ISC模式中，風速與風向在同一小時下為單一的，但在CALPUFF模式中，風場是由地面測站及探空測站的資料設定所決定。接下來，分別測試平坦地形、理想地形、平坦地形加上廠房效應以及理想地形加上廠房效應。點源位於建築物或是地形的上風及下風處分別作模擬。在ISC中，結果顯示當點源位於理想地形的上風時，撞擊濃度會極大。在PRIME方法中，建築物方位會影響濃度分佈，但在Schulman-Scire/Huber-Snyder中並不會。最後則測試容許增量限值。以二氧化硫的門檻值每年60公噸為基準，煙囪高度為35公尺高。結果顯示只有在ISC模擬平坦地形及CALPUFF模擬平坦地形及理想地形時，日平均濃度沒超過規範限值，其他則超過。地形及建築物效應應被考慮到影響污染物濃度擴散時的容許增量限值及法規標準中。

In order to know the complex terrain effects and building downwash effects, ISC model and CALPUFF model both are the main simulating tools for this research. Combining these two effects with different atmospheric stabilities and mixing layer heights, the maximum concentrations and distribution patterns are demonstrated in the graphs First of all, by comparing the basis of two air quality models, the differences can be understood. The wind fields are not similar in two models. In ISC, the wind velocity and wind direction is unique in each hour. In CALPUFF, the wind field is modified by the input of surface meteorological stations and upper air stations. Second, these are four cases be tested, which are the flat terrain, ideal terrain, flat terrain with building downwash, and ideal terrain with building downwash. The point source of each case is separately simulated as located at the downwind or upwind of terrain and building. The outcome is found that when the source is located the upwind of the ideal terrain, the impingement concentration is much larger in ISC model. The building orientation would only influence the concentration pattern in PRIME method, rather than in Schulman-Scire/Huber-Snyder method. Finally, allowable pollutant increase limits (APIL) are tested. Under the circumstances of the emission of sulfur oxide limited to sixty tons per year and on the stack height of thirty-five meter, by means of ISC tested on the flat terrain, the amount of concentration is less than law standard and as well as by the means of CALPUFF tested on the flat terrain and ideal terrain. However, the others failed. The conclusion is that if CALPUFF model is introduced into the preferred air quality models, the terrain effect and building downwash effects should be taken consideration into the allowable pollutant increase limits and law standard.