A Culture-independent Approach to Query The Composition and Dynamics of Airborne Bacteria Within Indoor Environments for Air Quality Improvements

Indoor air quality is an important public health matter because people in the developed world spend ~90% of their time indoor and inhale over 14,000 liters of air per day when performing normal activities. This topic is especially relevant and important in Hong Kong as it has the largest number of skyscrapers in the world with over 7,600 and in this densely populated city of 7 million people, many economic and leisure activities are held within indoor environments. One public health risk in the indoor environments is the transmission of contagious pathogenic microorganisms through the airborne route and sick building syndrome, where occupants experience acute health effects, discomforts and allergic symptoms, is another health concern that is thought to be associated with bioaerosols. The economic losses due to sick building syndrome can be substantial if employees require time off from work to recover.At the moment, much of the scientific knowledge regarding the bacteria that are present within indoor air has been derived from culturing studies. However, given that >99% of microbes are not culturable under standard conditions in the laboratory, this suggests that the bacterial diversity within indoor air has been substantially underestimated. Therefore, to gain better insights into the bacterial diversity within the indoor atmospheric environments, we propose an innovative research plan that uses advanced culture-independent molecular methods to query the composition and dynamics of airborne bacteria for the purpose of air quality improvements. Specifically, we will apply high-throughput pyrosequencing of the bacterial DNA to circumvent the drawbacks of culturing methods. By sampling diverse indoor environments that have different ventilation systems, construction materials, occupant loads, and building functions, we will come to understand the composition, diversity, gene content, and viability of the airborne bacteria as well as the correlation between environmental conditions and the dynamics of the bacteria. A throughout understanding of the airborne bacteria within the indoor built environments will ultimately enable us to derive best practices for improving indoor air quality and design buildings that can best protect the health of the occupants.