家用排油煙機移除粒狀汙染物之效能評估

Abstract

背景及目的: 暴露到烹飪汙染物可能產生不良健康效應，台灣非吸菸婦女的罹患肺癌風險與每日烹飪次數有正相關，並與排油煙機的使用有負相關。使用家用排油煙機可透過局部排氣及整體換氣降低室內的汙染物濃度，為常見的介入方式。現今美國研究已利用捕集效率及汙染物環境移除率定義家用排油煙機的效能，而臺灣家用排油煙機研究多為個案探討，其結果缺乏外推性與重複性，同時國內法規僅針對排油煙機流率做出規範。故本研究目的為使用系統性方法測試市售家用排油煙機移除不同粒徑之懸浮微粒之效能，包含(1)在兩個固定流量下，測試不同排油煙機款式對效能的影響。(2)依原廠排風量測試排油煙機之效能。 方法: 本研究從合計市占率為78%的四種排油煙機品牌挑選出25台排油煙機進行流量測試，並依據排油煙機的最高流率及流率範圍從而選出5台試驗機種。實驗藉由氣膠產生系統產生氯化鈉微粒並通過攝氏350度電熱箱後釋出以模擬烹飪污染物產生情形，並量測14.6-685.4奈米位於烹飪者呼吸區及排油煙機管道內微粒濃度，以計算排油煙機分徑捕集效率及環境微粒移除率。 結果與討論: 在固定流率測試中，觀察到微粒的捕集效率及環境效能會受到排油煙機的形狀、粒徑大小、流量影響。隨流率提升，微粒捕集效率受到排油煙機形狀之影響則較不明顯。在原廠流率測試下，低、中、高段速之分徑捕集效率分別介於47.9-89.6%、48.5-94.4%、41.7-95.7%；環境微粒之分徑移除率則分別為29.4-89.2%、48.0-94.8%、73.8-97.5%。且研究觀察到捕集效率在奈米微粒普遍較佳而在次微米的表現則較差，環境移除效能的結果則相反。 結論: 研究發現歐式、深罩式、隱藏式排油煙機在捕集效率上有較好的表現，傳統式及斜背式排油煙機在捕集效率表現則較差，此發現尚需更多的機種測試來證實。整體來說，提升排油煙機的流量則能普遍提升分徑捕集效率及環境移除率。

Background and objective: Higher lung cancer risk among Taiwanese non-smoking women was associated with the number of meals prepared per day and less usage of a kitchen hood during cooking. However, there were few Taiwan studies investigating kitchen hood performance and most of the local studies were case-specific with low generalizability. Furthermore, there was no standard method to estimate kitchen hood performance in Taiwan. The study objective was to apply a systematic method to characterize kitchen hood performance. There were two specific aims: (1) to investigate whether kitchen hood performance was affected by different kitchen hood type under fixed low and high flow rates; and (2) to evaluate the hood performance under the original flow settings. Kitchen hood performance was defined as “capture efficiency” (CE) and “effectiveness”. Methods: We selected 25 kitchen hoods from 4 common brands which consisted of 78% of the market share in Taiwan. 5 representative kitchen hoods were further selected based on the measured maximum flow rate and the wide flow range. Size-resolved CE and effectiveness were estimated from the steady states of artificially generated particle concentration in the study zone and the exhaust air of the kitchen hoods, with and without hood operation. Five flow rate scenarios were included for all hoods: the fixed low and high flow rates, as well as the original flow rate at low, medium, and high fan speed levels. Results and discussion: Under fixed flow rates, we found that CE and effectiveness varied by kitchen hood geometry, particle size, and flow rate. Flow rate was the dominating factor compared to hood geometry for CE under fixed high flow rate. For the original flow rate tests, CE ranged from 47.9-89.6%, 48.5-94.4%, and 41.7-95.7%, whereas effectiveness ranged from 29.4-89.2%, 48.0-94.8%, and 73.8-97.5% at low, medium and high speed levels, respectively. For the size-resolved performance, CE was relatively higher for ultrafine particles (UFPs) but lower for submicrometer particles, whereas effectiveness was of opposite results. Conclusion: For the 5 tested kitchen hoods, we found that European, extend-shell, and concealed type of kitchen hoods had better CE, whereas slope-side and traditional type of kitchen hoods had lower CE. Overall, higher hood flow rate led to increased CE and effectiveness for most particle sizes. In this study, we successfully established a method to systematically and quantitatively evaluate the kitchen hood performance, which can be used to survey a more comprehensive collection of kitchen hoods in the Taiwanese market in the future.