Indoor air quality in sleeping environments

An indoor air quality test was conducted in four bedrooms in Singapore. The occupants’ health and well-being were assessed through tests of cognitive performance and surveys of thermal comfort. In addition, the cognitive performance of some occupants were studied and compared to their sleeping environments, whether it was air-conditioned or fan-assisted naturally ventilated. The results showed that the air-conditioner was instrumental in controlling and maintaining indoor room temperature and relative humidity at acceptable levels. Temperature and relative humidity were two of the major factors affecting thermal comfort levels, and results revealed that at times when the temperature and relative humidity were not within the recommended guidelines by NEA, occupants felt that thermal comfort level was acceptable. It was inferred that the level of thermal comfort carried a very subjective definition, and was ultimately up to personal preference. The AER in NV conditions was much greater than in AC conditions, by scales of 10. The AER for NV conditions were well above the minimum AER of 0.35 /hour based on the guidelines from ASHRAE, but in AC conditions, the AER either fell short of 0.35 /hour, or were only slightly above this level. Emission rates of formaldehyde in the room under AC condition were found to be positively related to two factors, namely the age of the room and the average temperature of the indoor space. In terms of cognitive performance, people who usually slept in AC conditions had a tendency to perform better when sleeping in AC conditions, than when sleeping in NV conditions. For people who usually slept in NV condition, no relationship could be drawn about whether their cognitive performance was better in AC or in NV conditions.Bachelor of Engineering (Environmental Engineering