Air pollution and natural ventilation in an urban building: a case study.

In recent years, increases in pollution emissions resulting from an increase in vehicular traffic have caused great public concern regarding the quality of urban air and its impact on those working in these areas. In buildings this has led to an increase in the installation of air conditioning systems to 'clean' the incoming air. However, with environmental issues in mind such as high energy costs, the related C02 emissions and global warming, designers are increasingly being encouraged to consider natural ventilation as the primary design option. Concern about air pollution and external noise still remain and these are perceived to be major barriers in the design of buildings located in urban areas, although there is no real data to support this. BRE is thus carrying out a study of the levels of air pollution and noise in such buildings. This paper presents results of measurements carried out for a number of pollutants inside a naturally ventilated building located near a major road, where atmospheric pollution and noise levels are perceived to be high. The building, a recent design completed in 1994, incorporates a specially designed natural ventilation strategy with air supply intake from a courtyard away from the busy road. Ventilation rates within the building and external wind speed and direction were monitored to allow the pollution measurements to be put into context. Some noise measurements are also reported. An initial analysis of the ventilation strategy used in mitigating the effect of external pollution while providing adequate ventilation for the occupants has been made for the winter period.