McKernan Lauralynn Taylor, Wallingford Kenneth M, Hein Misty J, Burge Harriet, Rogers Christine A, Herrick Robert
Division of Surveillance, Hazard Evaluations, and Field Studies, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, 4676 Columbia Parkway, Cincinnati, OH 45226, USA.
Ann Occup Hyg. 2008 Mar;52(2):139-49. doi: 10.1093/annhyg/mem068.
Although exposure to bacteria has been assessed in cabin air previously, minimal numbers of samples have been collected in-flight. The purpose of this research was to comprehensively characterize bacterial concentrations in the aircraft cabin. Twelve randomly selected flights were sampled on Boeing-767 aircraft, each with a flight duration between 4.5 and 6.5 h. N-6 impactors were used to collect sequential, triplicate air samples in the front and rear of coach class during six sampling intervals throughout each flight: boarding, mid-climb, early cruise, mid-cruise, late cruise and deplaning. Comparison air samples were also collected inside and outside the airport terminals at the origin and destination cities. The MIXED procedure in SAS was used to model the mean and the covariance matrix of the natural log-transformed bacterial concentrations. A total of 513 airborne culturable bacterial samples were collected. During flight (mid-climb and cruise intervals), a model-adjusted geometric mean (GM) of 136 total colony-forming units per cubic meter of air sampled (CFU x m(-3)) and geometric standard deviation of 2.1 were observed. Bacterial concentrations were highest during the boarding (GM 290 CFU x m(-3)) and deplaning (GM 549 CFU x m(-3)) processes. Total bacterial concentrations observed during flight were significantly lower than GMs for boarding and deplaning (P values <0.0001-0.021) in the modeled results. Our findings highlight the fact that aerobiological concentrations can be dynamic and underscore the importance of appropriate sample size and design. The genera analysis indicates that passenger activity and high occupant density contribute to airborne bacterial generation. Overall, our research demonstrates that the bacteria recovered on observed flights were either common skin-surface organisms (primarily gram-positive cocci) or organisms common in dust and outdoor air.
尽管此前已对机舱空气中的细菌暴露情况进行过评估，但飞行过程中采集的样本数量极少。本研究的目的是全面描述飞机机舱内的细菌浓度。在波音 - 767飞机上随机选取了12个航班进行采样，每个航班的飞行时长在4.5至6.5小时之间。在每次飞行的六个采样间隔期间，使用N - 6撞击式采样器在经济舱的前部和后部连续采集三份空气样本：登机、爬升至一半高度、巡航初期、巡航中期、巡航后期和下飞机时。还在出发和目的地城市的机场候机楼内外采集了对照空气样本。使用SAS中的MIXED过程对自然对数转换后的细菌浓度的均值和协方差矩阵进行建模。共采集了513份可培养的空气传播细菌样本。在飞行期间（爬升至一半高度和巡航间隔），观察到每立方米空气采样的模型调整几何均值（GM）为136个总菌落形成单位（CFU×m⁻³），几何标准差为2.1。细菌浓度在登机（GM 290 CFU×m⁻³）和下飞机（GM 549 CFU×m⁻³）过程中最高。在建模结果中，飞行期间观察到的总细菌浓度显著低于登机和下飞机时的GM（P值<0.0001 - 0.021）。我们的研究结果突出了空气生物学浓度可能具有动态变化这一事实，并强调了适当样本量和设计的重要性。属分析表明，乘客活动和高载客密度会导致空气中细菌的产生。总体而言，我们的研究表明，在观察到的航班上回收的细菌要么是常见的皮肤表面微生物（主要是革兰氏阳性球菌），要么是灰尘和室外空气中常见的微生物。
