Research under the Managing Air for Green Inner Cities (MAGIC) project uses measurements andmodelling to investigate the connections between external and internal conditions: the impactof urban airflow on the natural ventilation of a building. The test site was chosen so that underdifferent environmental conditions the levels of external pollutants entering the building, fromeither a polluted road or a relatively clean courtyard, would be significantly different.Measurements included temperature, relative humidity, local wind and solar radiation, togetherwith levels of carbon monoxide (CO) and carbon dioxide (CO2) both inside and outside thebuilding to assess the indoor–outdoor exchangeflows. Building ventilation took place throughwindows on two sides, allowing for single-sided and crosswind-driven ventilation, and also stack-driven ventilation in low wind conditions. The externalflow around the test site was modelled inan urban boundary layer in a wind tunnel. The wind tunnel results were incorporated in a large-eddy-simulation model, Fluidity, and the results compared with monitoring data taken bothwithin the building and from the surrounding area. In particular, the effects of street layout andassociated street canyons, of roof geometry and the wakes of nearby tall buildings were examined.
