Improvement of the Indoor Air Quality in Housings of Ho Chi Minh City (Vietnam) by Adapting the Ventilation System to Minimize the Pollutants Concentrations

We spend about 90% of our time inside buildings, where we could control the quality of the environment for health, thermal comfort, security and productivity. The quality of the indoor environment is affected by many factors including design of the building, ventilation, thermal insulation, energy provision and use. It is evident from preliminary studies that Indoor Air Quality (IAQ) in Vietnam housing is under-researched and there is a clear lack of awareness among housing occupants of the harmful effects of chemicals that exist inside housings. Houses in warm-humid regions depend on large openings and through ventilation for thermal comfort. Openings allow air pollution and noise to penetrate these houses easily, thereby affecting the health, comfort and well-being of residents. Closing all openings and changing from natural ventilation to air conditioning is not however a practical solution for low cost housing.
As a result, the study was set out to review the previous related research studies in the field of IAQ, identify the current status of IAQ in HCMC, and find solutions to implement IAQ best practice in three sample houses as a pilot for achieving good IAQ.
Through this study, we found evidences that residents of rental houses were exposed to slightly high levels of CO2 during the night-time or at anytime when the occupants closed the door for sleeping or for personal activities. The indoor CO concentrations were over 20 ppm in rush hours in some houses which located nearby streets and opened the entrance doors for sale. We found that housing residents might be disproportionately exposed to high levels of PM2.5 and TVOC due to the presence of many indoor sources. Poor thermal comfort was also found to be a prevalent issue in most of sample houses, but there was not enough data on comparable indoor and outdoor to make a definitive statement about relative prevalence. Indoor air quality is influenced by location of the house, opening design, and opening behavior. Air quality in residential buildings, especially in the living-rooms, was generally poorer with the houses having no outlets to outside and no exhaust fans and this was true for both houses near or far from a road.
Lastly, the study indicated that there were feasible and practical solutions to the reduction of indoor air pollution in such housings by changing opening design, changing opening habits and applying local ventilation. The renovations were found high efficiency to reduce indoor CO and TVOC in hot and humid condition. Based on low cost development, this application can be applied with natural ventilation system in housings in big cities of Vietnam.