台灣地區室外空氣污染對健康效應之研究

在台灣地區，隨著經濟發展，快速工業化，使得各式工廠林立，這些工廠排放的廢氣，往往成為當地空氣污染的主要來源。而因著台灣地狹人稠，工業區與住宅區頂多相距區區數公里，因此，這些空氣污染物，便有可能會對鄰近居民的健康造成短期或長期的不良影響。　　本論文中呈現的即是多種空氣污染來源工業區之早產風險研究、火力發電廠鄰近居民之早產風險研究，以及空氣污染對於每日死亡人數以及每日腦血管疾病住院人數之急性健康危害研究。　　在南台灣的一個多種空氣污染來源工業區，婦女生出早產兒的機會顯著高於對照區，於調整母親年齡、教育程度、婚姻狀況以及新生兒性別、出生季節、出生地點等干擾因子後，調整後之危險對比值為1.11（95%信賴區間：1.02-1.21）。　　居住在火力發電廠0-3公里半徑內婦女之早產風險亦高於居住在半徑3-4公里內者，其調整後之危險對比值為1.14（1.01-1.30）。　　本論文的第二大部分是採用「病例自我對照」研究法來探討高雄市空氣污染濃度與每日死亡人數和每日中風住院人數之關係。在每日死亡人數的部分，PM10、SO2、CO、NO2和O3這五種污染物濃度與非意外之全死因死亡人數、呼吸道疾病死亡人數和循環系統疾病死亡人數均沒有統計上的顯著關係存在。　　在每日中風住院人數的部分，無論是阻塞性腦血管疾病或出血性腦血管疾病的住院人數，在暖天氣（? 20?C）、單一污染物模式時均明顯地與PM10、NO2、CO、O3有相關性，然而，在冷天氣時，只有阻塞性腦血管疾病與CO有統計上的顯著意義。進一步分析暖天氣、兩種污染物模式時，PM10和NO2在調整其他四種污染物後仍然有意義。PM10和NO2在出血性腦血管疾病住院人數之危險對比值分別為1.552（1.336-1.804）、1.589（1.364-1.852）；阻塞性腦血管住院人數之危險對比值則分別為1.461（1.323-1.613）、1.545（1.398-1.708）。　　本研究顯示多種空氣污染來源地區以及火力發電廠所造成之空氣污染確實會造成暴露區婦女有較高的早產風險。　　在高雄地區，空氣污染與每日死亡人數沒有顯著相關的原因可能包括氣候較熱，空氣污染來源不同、污染物混合程度不同等因素。此外，我們也為空氣污染與腦血管疾病的住院人數之關係提供了一項新證據。

關鍵字

空氣污染；早產；火力發電廠；病例自我對照；死亡；中風；住院；流行病學

並列摘要

The tiny island of Taiwan is densely populated and the distances between industrial districts and residential regions are commonly short. Therefore, comparatively speaking, it is even more important to investigate the effects of air pollution on adverse health outcomes in Taiwan. 　　The objectives of this study were (1) to determine whether women living in the specific air-polluted vicinity are highly correlated with increasing incidences of preterm births, and (2) to investigate whether air pollution is associated with daily mortality and daily hospital admission for stroke. 　　In a vicinity of industrial districts where emission levels of air contaminants from multiple sources including petrochemical, petroleum, steel and shipbuilding industries, we found that the prevalence of delivery of preterm birth infants was significantly higher in comparing the control regions. After controlling for several possible confounders (including maternal age, season, marital status, maternal education, infant gender and birthplace), the adjusted odds ratio was 1.11 (95% CI=1.02-1.21) for delivery of preterm infants in this industrial area. 　　Moreover, the prevalence of delivery of preterm birth infants was also significantly higher in mothers living within 0-3 km of thermal power plants compared to mothers living within 3-4 km. The adjusted odds ratio was 1.14 (95% CI=1.01-1.30). 　　To examine the relationship between air pollution and daily mortality/hospital admission in Kaohsiung, the largest industrial city in Taiwan, we used a case-crossover design which is an alternative to Poisson time series regression for studying the short-term adverse health effects of air pollution. For the period of 1994-2000, no significant effects were found between five pollutants (PM10, SO2, CO, NO2, O3) and non-accidental deaths, respiratory-related deaths and cardiovascular disease deaths. 　　For the period of 1997-2000, statistically significant positive associations were found between levels of PM10, NO2, CO, and O3, and both intracerebral haemorrhagic stroke (IHS) and ischemic stroke (IS) admissions on warm days (?20?C) in the single pollutant models. On cool days (<20?C), only CO levels and IS admissions were significantly associated. The two-pollutant models, PM10 and NO2 remained consistently and significantly associated with admissions for both types of stroke on warm days. We observed estimated relative risks of 1.552 (1.336-1.804) and 1.589 (1.364-1.852) for IHS for each interquartile range increase in PM10 and NO2. The values for IS were 1.461 (1.323-1.613) and 1.545 (1.398-1.708) respectively. 　　Our data provide further supports for the hypothesis that air pollution can affect the outcome of pregnancy, although a semi-ecological study cannot confirm a direct causal relationship. 　　The factors such as differences in meteorological condition, pollutant mixtures or underlying health of the population may explain the lack of a strong association between air pollution levels and daily mortality in Kaohsiung. Further studies of this type in cities with varying climates and cultures are needed. Nevertheless, this study provides an association between exposure to air pollution and hospital admissions for stroke.

並列關鍵字

air pollution ； preterm ； thermal power plant ； case-crossover ； mortality ； stroke ； hospital admission ； epidemiology

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