醫療院所室內空氣中真菌與細菌濃度評估與環境影響因子調查

Abstract

醫療場所因其作業環境對於室內空氣品質要求較高，尤其對於生物性汙染源，其可能造成就診者二度感染或加重病情，同時服務的工作人員也須承受長期暴露的高風險性。故本研究根據環保署環境檢驗所公告之室內空氣微生物標準檢測方法，採用安德森單階生物氣膠採樣器 (Andersen single-stage viable particle sizing sampler)，針對醫院空氣中真菌與細菌濃度做詳細的採樣調查，同時參考國內外文獻與法定標準值，評估生物暴露情況，另外也針對環境影響因素如月份、人數、二氧化碳濃度、溫溼度、室外空氣及時段 (早、午、晚) 以適當的統計方式研究其相關性。 根據研究結果，三所醫院所有監測場所的平均真菌濃度均符合環保署標準1000 CFU/m3以下，但細菌濃度則有59%的室內監測場所曾超出環保署標準500 CFU/m3，而這些不合格場所多是各家醫院的掛號及候診區。於微生物的環境影響因子方面，真菌濃度普遍於六月或八月夏季時節較高，細菌濃度則於十二月或二月冬季時節較低；而真菌濃度受室內人口影響的監測場所僅占4%，但有41%的監測場所其細菌濃度與人口數具有相關性；CO2濃度與真菌濃度具相關性的場所約占30%，其可能呈負相關或正相關，與監測場所的特性有關，而與細菌濃度具相關性的場所約占37%；而多數場所的真菌或細菌濃度皆與溫度有關，約占所有場所的44%，相較之下與濕度具相關性的場所較少，真菌方面約有15%，細菌方面則僅有3%；雖然多數文獻顯示室內真菌最大之汙染源來自於室外，但本研究分析結果僅有15%的監測場所其真菌濃度與室外空氣具有相關性，這些相關場所大多位於一樓且與室外具有門窗通道，而細菌方面則有30%的場所與室外空氣具相關性，另外汙水處理廠的存在會顯著增加空氣中細菌濃度；於時段上，約有26%監測場所的真菌濃度具有顯著差異，但依各場所不同而有所區別，細菌濃度則有52%的室內監測場所具有顯著差異，且大致上於晚上時段濃度較低。

The indoor air quality (IAQ) plays an important role in the human health and comfortability of occupants, especially in hospitals. The nosocomial airborne contamination in hospitals can arrive from non-biological and biological sources, which in-turn causes precipitating of symptoms and infecting disease in susceptible subject’s i.e. elderly or immuno-compromised subjects. The long term exposure to these nosocomial airborne contaminations can induce high risks for the hospital staffs. For analysis and maintenance protocols to comprise the hospital IAQ within the IAQ standards, I use the Andersen single-stage viable particle sizing sampler to investigate the presence of bacteria and fungi in the indoor-air of a hospital at different time frames. In addition, we intend to investigate the relationship between IAQ and various environmental factors such as person, CO2 concentration, temperature, relative humidity, month, and time (morning, afternoon, evening). Finally, a comparison of the present IAQ of hospital with IAQ standards of various countries including Taiwan will be briefed. The monitoring results reveal that the average fungi concentrations in most hospital rooms can comply with the suggested standard which is under 1000 CFU/m3. On the contrary, the bacteria concentrations of 59% of monitoring sites had been over the standard value 500 CFU/m3, and thses sites were mostly registry or wating rooms.On the other hand, this study uses suitable statistical method to analyze eight interfering factors. First, the fungi concentrations were generally higher in June or August, but the bacteria concentrations were usually lower in December or February. Second, there were only 4% of monitoring sites whose fungi concentrations were significantly correlated with person, but there were about 41% of sites whose bacteria concentrations were. Third, there were 30% of sites whose fungi concentrations had positive or negative relationship to CO2 concentrations, and the reason may be in connection with the characteristics of sampling sites. In addition, there were 37% of sites whose bacteria concentrations and CO2 concentrations were directly related. Forth, the proportion of monitoring sites whose both fungi and bacteria concentrations were significantly correlated with indoor temperature is 44%. By contraries, the proportion of sampling sites whose fungi and bacteria concentrations had relationship with related humity is only 15% and 3% respectively. Fifth, although many study indicate that the most serious fungi pollution sources in door come from outdoor air, this study results reveal that there were marely 15% of monitoring sites whose indoor and outdoor fungi concentrations were significantly correlated with each other, and the most parts of these sites were on the first floor and connected wih outdoor air by doors and windows. On the other side, the proportion of sampling sites whose bacteria concentrations were significantly correlated with outndoor air is 30%. Moreover, the existence of sewage treatment plants also can increased the nearby airborn bacteria concentration significantly. Sixth, the proportion of sampling sites whose fungi and bacteria concentrations had significantly different from time to time were 26% and 52% respectively, and the bacteria concentrations sampling at night are lower than other timess, like in morning or afternoon.