Abstract
摘要:流行病學及毒理學研究已經指出大氣細懸浮微粒(Fine particles, FP)空氣污染之健康效應,台灣目前已經制定大氣細懸浮微粒標準,但是對於微粒物理化學特性與毒性的相關相對不足。過去人造奈米微粒研究發現數目濃度與表面積,相較於重量濃度,可能更能反應微粒毒性。另外,大氣微粒的粒徑與產生來源有關,其成分也會不同,可能影響微粒毒性。所以有關超細懸浮微粒(Ultrafine particles, UFP) 的研究相對不足,實有必要進行對其毒理做進一步研究。UFP的採樣及暴露系統有高技術難度,相關測量儀器也較缺乏,除了要收集到足夠進行暴露實驗的UFP不容易外,以實際大氣UFP進行急性與慢性暴露之毒理實驗更面臨許多研究限制,臺灣地區過去也缺乏研究團隊解決此一重要環境健康議題。本研究團隊嘗試探討UFP之健康效應,本子計畫將分別以氣管灌注以及微粒暴露系統進行動物實驗,比較急慢性呼吸暴露UFP與FP的心跳、血壓及心律變異性,氧化壓力與發炎反應等機轉變化,還有器官功能與組織傷害等效應,同時將探討質量、數目與成分與毒性之相關。第一年我們使用已開發的大氣微粒暴露系統,探討微粒的質量,數目及成分,與微粒毒性之相關。本實驗室已經成功開發大氣微粒暴露系統,本系統構造簡單,維護容易,可以取代原來使用的南加大微粒濃縮系統,並已經成功使用於亞慢性暴露。我們使用重複交換暴露的設計,每隻動物重複暴露台北市大氣四星期,兩次暴露之間暴露過濾空氣,可以減少動物的數目,並達到統計效果。本實驗也同時使用Dust monitor監測細懸浮微粒濃度,並使用SMPS來監測微粒數目濃度,代表超細微粒的效應,同時也偵測黑碳濃度,代表交通污染,另外,以濾紙收集微粒,分析元素碳及有機碳,還有離子成分等,動物植入血壓及心電圖監測儀器,並以無線傳到接受器,收集的資料做進一步分析。暴露期間細懸浮微粒濃度約16ug/m3,結果顯示細懸浮微粒質量濃度與血壓心跳有關,而數目濃度及黑炭與心跳血壓無關,同樣的,細懸浮微粒質量濃度與心律變異有關,而數目濃度及黑炭與心律變異無關。我們也發現心跳與有機碳及元素碳,硝酸鹽、氯及鈉離子等有關,而血壓可能與硝酸鹽、氯及鈉離子與有關,心律變異與氯離子及硝酸鹽有關。我們發現在都市交通污染源為主的暴露,細懸浮微粒比較超細懸浮微粒,對於心跳血壓及心律變異性的相關性較大,而與這些變項有關的成分主要是氯離子及鈉離子等與海鹽相關離子,還有機碳及無機碳,其來源值得進一步探討。在未來計畫中,我們將採集超細及細粒徑微粒進行動物氣管灌注,進一步比較超細及細粒徑微粒的發炎及氧化壓力,並探討成分與毒性之相關。
Abstract: Previous epidemiological and toxicological studies have indicated the health effects of ambient fine particles (FP) air pollution. Taiwan has established a FM standard. However, the relationship between physicochemical characteristics of PM and toxicities remains unclear. Previous studies have shown that number concentration and surface area, compared to mass concentration, may be more important for particle toxicity of manufactured nanoparticles. Further, the particles of different sizes may have different compositions and toxicities. Meanwhile, the collection and exposure experiments of ultrafine particle (UFP) were not easy. There were few researchers in Taiwan investigating this issue before. In this sub-project, we investigated the toxicity of UFP in animals. In the first year, we used a fine particle exposure system to determine the toxicities of UFP and FP with mass and number concentrations, and compositions. This exposure system has been demonstrated to be easy to operate and maintain. We have used this system to study the sub-chronic toxicity of ambient PM. Under the crossover self-controlled design, animals were exposed to 4 weeks of whole air. Between each week, they were exposed to filtered air as controls. Dust monitor was used to determine the PM mass concentrations during exposure. SMPS was used to determine the number concentrations of PM. Black carbon and ozone were also measured. The PM was collected and analyzed for organic and elemental carbons, and ions. Animals were implanted with a probe for blood pressure and EKG monitoring. It was estimated the average concentration during exposure was about 16ug/m3. The results showed that FP mass concentration was associated with heart rate, blood pressure and heart rate variability, while number concentration and black carbon did not have effect. We also found that heart rate was associated with organic and elemental carbons, nitrate, chloride and sodium ions. Blood pressure was associate with nitrate, chloride and sodium ions. Heart rate variability was associated with chloride ion and nitrate. We conclude that FP has greater effects on heart rate, blood pressure and heart rate variability as compared to UFP in the city. The toxicity related sources need further study. In the future study, we are planning to collect FP and UFP, then compare their oxidative stress and inflammation. The relationship between toxicities and PM components will be further elucidated
Keyword(s)
空氣汙染
超細懸浮微粒
細懸浮微粒
暴露系統
氧化壓力
心肺毒性
Air pollution
Ultrafine particles
Fine particles
Exposure system
Oxidative stress
Cardiopulmonary toxicity