EVALUATION OF OCCUPANTS � PERCEPTION ON INDOOR AIR QUALITY AND PREVALENCE OF SICK BUILDING SYNDROME BEFORE AND AFTER INTERVENTION ON A RETROFITTED OFFICE ENVIRONMENT

Abstract

The NEA is a governmental agency that governs public health cleanliness. Occupying 3 levels in HDB Hub building, the indoor premises underwent retrofitting in 2012 to better improve the working environment and its aesthetics. After retrofitting, there were numerous complains on air quality from occupants in levels 26 and 28 office. As such, the procurement team took up the responsibility to introduce several interventions to improve the IAQ in November 2012. Due to limited studies that focus on the effectiveness of interventions in improving occupants' health, this dissertation aims to examine the SBS before and after the interventions. Air pollutants that were treated by the control methods are measured to observe correlation between the SBS and changes in concentrations of air pollutants. The study includes comprehensive surveys concerning occupants' perception and health conditions. The surveys were taken in 2012 and 2013, both before and after interventions. There was a one year gap to allow a time buffer for improvement in IAQ to take place. Objective assessment was included to better understand the perception of occupants'. The objective measurements included specific chemical parameters which were targeted by the interventions as well as the thermal comfort parameters which was found to be compromised due to the interventions. Although there were improvement in prevalence of SBS, some other perceptions got worse instead. There were more occupants feeling stuffy in the office. It was found that ventilation rates was compromised due to expected improvement in IAQ with the interventions. Overall, less than 80% of the occupants were satisfied with the IAQ parameters even though there were indicators of improvement. Formaldehyde remains higher than thresholds specified in the SS554 standard even though it reduced after the interventions. As a result, recommendations such as purging during non-operational hours, increasing air movement while reducing indoor temperature and a SBS feedback system were proposed to better improve the wellbeing of occupants in NEA office.