[Hygienic investigation of indoor environment in air-conditioned passenger trains].

Objective: Explore the hygienic status of indoor environment in railway air-conditioned passenger trains.

Methods: We carried out a hygienic investigation of various air-conditioned passenger trains on total 10 railway lines in Shanghai, Chengtu, Kunming, Harbin, Urumchi and Guangzhou railway bureaus for two years between July, 1997 and Oct., 1999.