為了避免在測試中心內取得的結果與現實環境有太大差距，此研究亦選擇了20間食肆的廚房作現埸測試。結果顯示，運水煙罩、油隔、靜電除油器的最高除油煙效能，分別為84%、56% 和 52%。結果亦顯示部份控制油煙設備的效率相當低，甚至顯示負效率。這些差異可能是由於在實地研究中所採用的設備有不同的設計或類別，及抽取樣本中所含的油煙不穩定而引起。此外，不足夠的油煙控制設備、操作不當和維修不足，如靜電排油器等設備，都是引致低控制效率的主要原因。
Report On The In Vivo Study Of Cooking Fume Removal Efficency Of Common Pollution Control Equipments In Hong Kong
Cooking emissions is one of the major sources of air pollution owing to the highly compact environment and the large number of restaurants in Hong Kong. In order to combat the problem, a range of control equipments such as hydrovent, grease filter, water scrubber and electrostatic precipitator, are mostly deployed in the restaurants of Hong Kong..
However, some control equipments, perhaps with lower cooking fume removal efficiency, are relatively more vulnerable to complaints. Under this context, a Standard Testing Procedures (STP) on air emission testing, which is primarily based on the isokinetic stack air sampling (USEPA method 5), was developed by EPD and with the support from the academy. The cooking fume removal efficiencies of single pollution control equipment together with different combination of equipments were evaluated in a mock kitchen equipped with a standard test-rig. Hydrovent together with electrostatic precipitator was found to have highest cooking fume removal efficiency.
Furthermore, in order to bridge the gap between this result obtained in the testing laboratory and real-life kitchen, a territorial-wide survey of the performance of common pollution control equipments in 20 commercial kitchens was conducted in this study. The maximum cooking fume removal efficiencies of hydrovent, grease filter and electrostatic precipitator in commercial kitchens were found to be 84%, 56% and 32% respectively. However, some pollution control equipments showed poor performance or even with negative cooking fume removal efficiency. The large variation in the performance of the control equipments, even with same type of equipment, in the in vivo study was attributed to the difference in the equipment design and the unstable cooking fume level generated during sampling. Inadequate installed capacity, improper operation and maintenance of control equipment such as electrostatic precipitator were also the major reasons for the ineffective control of emissions.
● Grease Filters (油隔)
● Hydro-vent (灑水式煙罩[運水煙罩])
● Air-washers (空氣清洗器)
● Electrostatic precipitators (EP) (靜電除塵器)
● Venturi-Scrubber (文丘里式洗滌器)
● Packed Tower Scrubber (填充塔式洗滌器)
● Carbon Filters (活性碳隔濾器)