目標：探討近年來全台灣0-6歲兒童氣喘首次發生率，與環境監測之空氣汙染物濃度的關係。方法：以2007年至2011年之全民健康保險研究資料庫承保抽樣歸人檔40萬人，依據國際疾病分類法第九版(ICD-9-CM)診斷碼，篩選6歲以下第一次發生氣喘兒童為研究對象，並使用2006與2011年間環保署空氣品質監測數據PM_(10)、SO_2、NO_X(NO及NO_2)、CO及O_3之濃度資料，探究首發氣喘與空氣汙染物之相關性。結果：室外的空氣汙染物，以NO_X、CO與學齡前兒童首次氣喘發病關聯性顯著(ρ ＞ 0.5)，而此二者間相關性也高於其他任何汙染物種間的關聯(ρ = 0.892)，推測NO_X及CO主要來源為交通排放。進一步以多變項邏輯斯迴歸分析，發現暴露於高濃度NOX(＞ 16.3 ppb)導致氣喘發病比低濃度具有顯著勝算比，最高可達1.45(95%CI: 1.13- 1.86)。由於並無直接證據顯示NO_X、CO可導致氣喘，因此推論台灣學齡前兒童的氣喘首發率，應與交通排放汙染物相關。結論：交通排放汙染物與氣喘發病相關性高，建議民眾做好個人防護，並時時注意空氣品質資訊，以降低學齡前兒童氣喘發病機率。

Objectives: This study determined the incidence of the first occurrence of asthma in preschool children (0-6 years of age), and the relationship to air pollutants. Methods: Based on the Longitudinal National Health Insurance database (n=400,000) from 2007-2011, the study identified eligible asthmatic subjects in accordance with the 9th version of the international disease classification (ICD-9-CM), and used the local environmental monitoring data of PM_(10), SO_2, NO_X (NO and NO_2), CO, and O_3 from the Environmental Protection Administration (EPA) to relate to the first incidence of asthma for the eligible subjects. Results: Among the air pollutants, NO_X and CO were significantly associated with asthma, and were highly correlated with each other (ρ = 0.892), suggesting that NO_X and CO should have originated from transportation exhaust. The multivariate logistic regression analyses showed that high levels of NOX (＞ 16.3 ppb) resulted in significant odds ratios of asthma exacerbation up to 1.45 (95% CI: 1.13 - 1.86) compared to low levels. Because of no direct evidence showing that NOX or CO triggered asthma, it is suggested that the first incidence of asthma in pre-school children is related to transportation exhaust. Conclusions: Asthma in pre-school children was significantly associated with transportation exhaust. It is recommended that attention should be paid to personal care and information of air quality to lower the chances of asthma occurrence for preschool children.