Analysis of pedestrian-level wind velocity in four neighbourhoods in klang valley

Urban ventilation is important for the purpose of pollution dispersion, indoor ventilation for free running buildings and urban thermal comfort. In comparison to suburban cities, highdensity cities have very low wind speeds at pedestrian level due to the densely built buildings blocking the wind and creating stagnant zones locally. Under this circumstance, field measurements were performed to investigate the performance of pedestrian wind at four major cities in Klang Valley. Mean wind speed was measured using anemometers at 1 minute data interval for 3 hours and the data collection for each case were obtained at pedestrian level. The mean wind speed ratio was plotted against the frontal area ratio and plan area ratio. The result indicates that: (1) the mean wind speed dramatically decreases with the increase of plan area ratio and (2) the mean wind speed exponentially decreases with the increase of frontal area ratio and qualitatively agrees with the power law relationship which is proposed by previous researcher. In addition, the frontal area ratio is considered as a better parameter to evaluate the performance of urban ventilation