日益嚴重的空氣污染問題已影響了大自然的生態平衡，而對人類的生活也產生了一定的影響。隨著各地區工業化與都市化的不同，空氣污染的程度亦有所差異，所以在本研究中，以臺灣22個縣市為研究地區，並使用空氣污染指標（pollutant standards index ; PSI）中的懸浮微粒、二氧化硫、一氧化碳、臭氧和二氧化氮五種污染物為污程程度判斷的依據。本研究主要是以多目標決策中五種不同權重取法，來探討臺灣各縣市空氣污染的情形，也就是各項指標數據以平均法、準差法、CRITIC法(Criteria Importance Through Intercriteria Correlation)、熵值權重法及灰關聯分析，來取得權重後，再經加權計算而求得綜合指標值，同時依據綜合指標數值的高低比較各縣市空氣污染的嚴重情形，最後將上述五種分析方法與傳統PSI指標方法所得的結果比較，並探討之間的相關性，實證結果顯示在22個研究的縣市當中污染最嚴重的三大縣市為高雄市，高雄縣及嘉義市，最不嚴重的三大縣市則為臺東縣、宜蘭縣及新竹縣。

The air pollution is getting more and more serious and has affected the balance of the natural environment, and this will also have a serious impact on human life. According to the different degrees of industrialization and urbanization in different areas, the degrees of air pollution will not be the same. In this research twenty-two counties have been studied for those pollutants (suspended substances, □, □, □, □ and □) to indicate the degree of air pollution. Given these five environmental indicators, we will try to integrate these indicators and derive a single overall index. The ways to decide the weights includes Mean weight, Standard Deviation weight, CRITIC (Criteria Importance Through Intercriteria Correlation), Entropy method and Grey Relational analysis. Furthermore, the condition of air pollution will be compared in every county according to the aggregate index. Finally, the five methods are compared with the traditional Pollutant Standards Index (PSI) and the correlations among them are discussed.