The purpose of this survey is to know the actual conditions during the summer of the residential indoor environment in urban area in China. The apartment houses under investigation were sited in urban area of Changsha, and Beijing. The questionnaire survey and the measurement of indoor temperature and humidity were carried out in the summer of 2002. The questionnaire survey revealed the life style of summer season and the way of use of air-conditioner. The measurement showed that indoor temperature and humidity in Changsha and Beijing were relatively high. In some houses, it was found that the concentrations of formaldehyde and acetaldehyde were relatively high.
