Room-scale analysis of spatial and human factors affecting indoor environmental quality in Porto residential flats

Residential indoor environment quality (IEQ) is not fully known, particularly in Southern European countries. In this study, a room-level analysis was performed in forty-two rooms of twelve flats, selected from six buildings located in Porto, Portugal. Each room was monitored for approximately three weeks during the spring. The average monitored values in terms of temperature (T), water vapour pressure excess (Delta P), carbon dioxide (CO2), small particulate matter (PM2.5), the ratio between the indoor and outdoor PM2.5 (PM2.5 I/O), and total volatile organic compounds (TVOC) were 21.7 degrees C, 175 Pa, 781 ppm (1287 ppm considering only night occupancy periods), 12.2 mu g/m(3), 3.3 and 345 ppb, respectively. The CO2 concentrations and PM2.5 I/O values were higher than those obtained from the literature, indicating poorly ventilated rooms. A knowledge discovery methodology was used to search for behavioural patterns. Four groups were formed based on a cluster analysis that was qualitatively classified in terms of IEQ. Decision trees were created to evaluate the spatial and human factors affecting these cluster associations. The main factors affecting the IEQ were the presence of smokers, room ventilation ratio, floor area, and number of occupants. The results of this post-occupancy evaluation provide information to optimise the IEQ of the residential sector at the design level and emphasise the existence of a post-occupancy monitoring system that provides occupants with information about IEQ.