Predicting natural ventilation in urban environments is a complex and difficult problem to tackle. Without advanced experience in computational fluid dynamics and environmental simulation, predicting airflow around buildings and at street canyons is beyond the reach of most urban and building designers. This book attempts to provide designers with an easy method for approximating shielding effects of surrounding buildings on vertical facades. Using hundreds of wind tunnel simulations, the author developed a mathematical model using geometric relationships between the surface under consideration and the adjacent blocks. The appendices provide a rich source of wind tunnel data of surface pressures under several shielding conditions.