PRE AND POST IAQ MONITORING ON A NEWLY REFURBISHED AIR-CONDITIONED BUILDING

Abstract

An indoor air quality audit was conducted in two floors of Toa Payoh Housing and Development Board (HDB) Hub to evaluate the improvements to IAQ after mitigation measures to reduce formaldehyde level have been implemented. It aims to determine if the intervention measures were sufficient in eliminating the high concentration of pollutants by comparing to the pre IAQ results to assess the quality of the indoor air and the differences after one year. The audit comprises two components- objective measurement and subjective assessment. Apart from spot measurements, continuous measurements are also carried out to further study the profiles of certain IAQ parameters. From the results of the field measurements, it was found that the operative temperature, air movement and formaldehyde did not meet the threshold stated in SS554:2009. In some locations, there are also high concentrations of bacteria and mould count. Based on the survey conducted with the occupants, they are said to experience many symptoms regarding dryness. This could be due to the fact that the temperature was too cold and the air movement was too still for their liking. Hence, it is indicative that the indoor air quality is still not ideal in providing a healthy environment because of the dissatisfaction in thermal comfort parameters and the persistent high levels of formaldehyde. As such, it is proposed that certain measures such as improving the ventilation system as well as carrying out frequent maintenance for the air-conditioning and mechanical ventilation (ACMV) system are put in place. Dehumidifiers can also be used to try to reduce formaldehyde levels. Lastly, space planning can aid in enhancing occupants’ satisfaction with the thermal comfort level in the building.