Based on results of the routine air monitoring in Guangyuan city from 1990 to 1998,joining the progress of Guangyuan’s comprehensive environmental control,this paper analyzes and discusses its air quality and changing trend

METHODS Air surveillance methods,cleaning methods of intakes,cleaning status of pipelines and frequency of renewing filter systems were investigated through interviewing charge nurse of 18 hospitals by questionnaires.

Regional air monitoring network construction strategy and practice;

With respect to the current problems of air monitoring location,an experimental investigation of location norms has been carried out, and a new kind of pair monitoring method is put forward so as to provide criteria for comparison and assessment of air quallity.