Health Effects from Work in Ultra-low Humidity Environments

[[abstract]]台灣是海島型氣候，所處的環境之相對濕度經常介於60-90%範圍，也是一般人所能接受的環境條件。然而，在論及工作環境之濕度與健康的效應時，就較少有研究文獻被提出討論。本研究即針對極低濕度環境對作業者健康影響研究。 本研究分別從體內含水狀態、眼睛乾燥、皮膚乾燥及嗅覺敏銳性等方法，來量測在極低濕度環境(暴露組)與一般空調作業環境(對照組)之差異，藉以評估極低濕度環境對作業者健康影響程度。 在極低濕度環境下作業者其體內含水狀態部份，以複邏輯式迴歸分析調整其他干擾因子後發現暴露組比對照組有13.23倍(95% 信賴區間 = 2.78-62.9)的機率會發生尿比重濃縮(USG ≧ 1.030)的現象；在眼睛乾燥部份，極低濕度環境下作業者兩眼淚液分泌量有明顯減少，以Wilcoxon pair test分析有明顯統計差異(p<0.05)；在皮膚乾燥部份，暴露組人員在經皮水份蒸發速率明顯比對照組小(8.3±0.4 vs 10.0±0.4, p=0.047)，在進入極低濕度環境作業2週，在經皮水份蒸發速率及皮膚含水量有明顯減少20%以上，在作業1-20月期間，皮膚會慢慢回復的現象；嗅覺敏銳性部份，發現極低濕度因素會影響嗅覺敏銳閾值(r=0.72, p<0.001)，暴露組人員比一般空調環境作業人員對氣味嗅覺敏銳閾值更敏銳(p<0.001)。為避免低濕度環境影響到作業者健康，實施預防管理改善措施，在體內含水狀態及眼睛乾燥部份均獲得良好成效。 在極低濕度環境下作業會對人體產生”乾燥”影響，或多或少會影響到人的健康，可經由預防管理改善措施，讓低濕度環境下之作業者減緩低濕作用對健康上的影響。[[abstract]]Few studies have been conducted to investigate the health effects from work in ultra-low humidity (ULH) environments. The first purpose of the study was to assess the health effects among workers in ULH clean rooms with relative himidity (RH) < 2 using different evaluation methods such as body hydration status measurement, dry-eye testing, dry skin testing and olfactory sensitivity testing. The second purpose of the study was to the evaluate effectivities of administrative managements to workers for ULH harm reduction in the dry-rooms. Different ULH harm evaluation methods were conducted in the ULH environment workers (exposure group) as well as in the officers who work in normal air conditioning environment (control group). In the body hydration status measurement, after adjusting for age, gender, employment duration and body surface area, we found that working in the ULH environment was associated with an odds ratio of 13.23 (95% CI = 2.78-62.9) of having abnormalconcentrated urine (USG≧1.030) compared to the comparison group. In the dry-eye testing, the tear film quantity for ULH environment workers were obvious decreased than that for the comparison group (Wilcoxon pair test, p<0.05). In the dry skin testing, ULH exposure group were obvious transepidermal water loss (TEWL) smaller for the comparison group(8.3±0.4 vs 10.0±0.4, p=0.047). The ULH exposure were obviously reduced in the first 2 weeks of ULH exposure by skin TEWL and water contact (WC) for exposure group; however, the skin will be recovered slowly within 1-20 months in the same ULH environment. The results of the olfactory sensitivity testing the discovery ULH factor can affect the olfactory sensitivity (r=0.72, p<0.001). The olfactory sensitivity threshold (OST) for ULH environment workers were more sensitive than that for the control group (p