In year 1970s, many buildings are designed to reduced ventilation rate in order to maintain the indoor environment more efficiently and save electricity due to the energy crisis that happened. The construction of buildings with energy-efficient air conditioning system has caused sick building syndrome (SBS) to prevail in Malaysia as a result of poorly maintained air conditioning system, raising the levels of indoor air pollutants. Studies have shown that the occurrence of SBS is affected by type of ventilation of the building, with higher risk in buildings with mechanical ventilation system (MVAC) compared to normal ventilation system. There are a few studies done in tropical countries focusing on the relationship between the age of building, indoor air pollutant characteristics and the prevalence of SBS and other health effects. High concentration of total volatile organic compounds (TVOC) is normally found in new buildings while high concentration of carbon dioxide is found in old building caused by poor ventilation. Poor ventilation and high indoor air pollutant concentrations can lead to SBS, with non-specific symptoms such as irritated eyes, nose or throat, cough, tight chest, wheeze, headache, tiredness and difficulty in breathing. Thus, this study was carried out to investigate the relationship between the age of building and the likely occurrence of SBS in Malaysian buildings.
The concentration of carbon dioxide in the air is the main indicator for the efficiency of air supplied through the ventilation system. The new building showed a lower carbon dioxide level, indicating a better ventilation compared to the old building. Even though the ventilation measurement of the old building was lower than the standard set by American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE), it was still acceptable according to the Code of Practice on Indoor Air Quality set by the Department of Occupational Safety and Health (DOSH) Malaysia. A ventilation measurement lower than the ASHRAE standard might cause thermal comfort issues and the accumulation of indoor air pollutants that can lead to SBS symptoms. To improve the building ventilation, the effectiveness of ventilation system (bringing in more fresh air from the outside), its maintenance, cleaning procedures and periodical inspection should be done.
For indoor air pollutants, the old building had a higher levels of carbon monoxide, TVOC and particulate matters (dust) with sizes of 10 and 2.5 microns compared to new building. On the other hand, the new building had a much higher concentration of ultra fine particles (less than 0.1 micron in size). Even though the old building had a higher concentrations of all indoor air pollutants except ultra fine particles, all the readings were below standards set by DOSH, indicating that the ventilation systems of both buildings were well maintained. The lack of good ventilation in the old building might be caused by the high rise structure of the building that affect the air exchange or the blockage of the humidifier by people's activities and renovation. An increasing carbon dioxide concentration means an increasing risk of SBS occurrence.
To investigate the susceptibility of SBS occurrence, questionnaires were given out to the office workers in both buildings. One point was given if one SBS symptom happened nearly everyday, two points were given if there were two symptoms and so on. The results showed that 68.8% of office workers in the old building and 36.1% of office workers in the new building were having SBS symptoms. Besides carbon dioxide, there was a strong relationship between the SBS that happened and indoor air pollutants such as carbon monoxide and TVOC. Even though carbon monoxide which usually comes from car park is a strong factor of SBS, carbon monoxide in both buildings were lower than the standards set by DOSH, proving that carbon monoxide is not the main factor of SBS occurrence. There was an obvious relationship between TVOC and SBS occurrence among the office workers as well.
As a conclusion, an increase in the building ventilation rate can significantly reduce SBS issues besides improving the ventilation effectiveness and the reduction in sources of indoor air pollutants. For new buildings, ultra fine particles are the common nuisance that need to be paid attention to as they can also influence SBS. The raising public awareness regarding the importance of air ventilation towards health has induced concern about the indoor air quality. Many mitigation strategies have been implemented to solve indoor air quality issue over the years which require the involvement of building management from areas in
1) Facility management
3) Policy making
4) Staff training
to reduce occurrence of SBS among office workers, making the working environment safer and healthier for productivity.
Syazwan, A. I., Juliana, J., Norhafizalina, O., Azman, Z. A. & Kamaruzaman, J. (2009). Indoor air quality and sick building syndrome in Malaysian buildings. Global Journal of Health Science, 1(2): 126 - 135.
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