医院内的交叉感染可通过院内各种渠道进行。空气作为交叉感染的传播介质已逐渐引起预防医学界人士的关注。据文献报道由空气中微生物造成呼吸道感染一项就约占院内感染总数的15～20％,每年耗资达20亿美元之多。目前世界各地在进行院内疾病监测中已十分重视空气中微生物污染。 Cross-infection in the hospital can be carried out through various channels in the hospital. Air, as a transmission medium for cross-infection, has gradually drawn the attention of the preventive medicine community. According to the literature, airborne microorganisms cause respiratory infections, accounting for about 15 to 20% of the total number of nosocomial infections, costing as much as 2 billion U.S. dollars each year. At present, the monitoring of intra-hospital diseases in the world has attached great importance to microbial contamination in the air.