Abstract:
Due to rapid urbanization in developing countries more and more multi storey buildings including
high-rise buildings are constructed along the main roads obstructing the air movement. With the
increased traffic densities, vehicular air pollutants tend to be stagnant near the ground level, allowing
vertical dispersion to be prominent which requires a detailed study. Even though there are studies on
the vertical dispersion of air pollutants in the troposphere, only a few numbers of studies has been
carried out to investigate the air pollutant variation with respect to the height of a middle-rise building
which also can be affected by the local conditions. This study was aimed at investigating the vertical
profile of air pollutants of middle-rise buildings located adjacent to a road which is having the highest
annual daily traffic in Colombo, the capital city of a developing country, Sri Lanka. In the selected
building which is having eight stories, short term measurements of NCL, CO2 and PM2.5
concentrations were obtained in five locations at each floor level covering free running and air
conditioned spaces. The measurements were taken for five days during office hours. The experimental
results show a negative trend of NO2 and PM2.5 distribution with height of the building whereas the
vertical profile of CO2 concentration shows a positive trend in the free running spaces. Diverging
from this observation, the pollutant concentrations in the mechanically ventilated spaces show a
random variation with the increasing height. These results will aid the building planners to design and
plan the building ventilation system in order to maintain comfortable and healthier indoor
environment.
