INDOOR AIR QUALITY OF SCHOOLS: A CASE STUDY APPROACH

Abstract

This study aims to investigate the level of indoor air pollutants in selected schools for different types of class rooms and level of activities in Singapore. Indoor air quality (IAQ) parameters in five tertiary school buildings were measured during the period between year 2013 and 2014. In each school building, carbon dioxide (CO2), carbon monoxide (CO), operative temperature (OT), relative humidity (RH), respirable suspended particulates (RSPs), total volatile organic compounds (TVOCs), formaldehyde, air velocity, total bacterial count and total fungal count compare the air quality to SS554 Code of Practice for Indoor Air Quality for Air-Conditioned Buildings in Singapore were performed during school hours, and a complete walkthrough survey was completed. The results show that elevated levels of carbon dioxide and bacteria were found in lecture theatres when it is occupied. This could be due to the high occupancy with insufficient ventilation. Introduction of more fresh air and better air circulation can help to alleviate the problem. The OT results at several locations were found to be lower than the recommended range of between 24-26°C. Generally, in a well maintained building, it would be reasonable to maintain the operative temperature at around 24°and 26°C. The goal should be to maintain the temperature that will satisfy at least 80% of the occupants. Air movement in a few indoor locations were found to be lower than the recommended range. This may not have direct influence over occupant’s perception in indoor environment as compared to temperature and humidity. However, it is synergistically related to the thermal comfort and the overall performance of the ventilation system. Too high or low air movement will affect the thermal comfort of individuals. Total bacterial counts at many indoor locations exceeded the recommended threshold limit of 500CFU/m3. Human occupants themselves are normal reservoirs of bacteria; the level of airborne viable bacteria is based on the number of occupants and their activity at the site. Bacterial impurities found in the indoor environment should normally be removed through the ventilation systems and cleaning procedures. Improving the ventilation system and routine cleaning or regular house-keeping should lead to lower level of airborne bacteria.