For EBC collection, a simple impinger type saliva trapping device was connected to the front end of the EBC collecting tubing, this device can effectively prevent the pollution of EBC by saliva.

• EBC的收集方面，于采样管最前端加装一个如冲击瓶形式的唾液捕集装置，此装置可有效避免EBC受到唾液的污染。