Building ventilation and indoor air quality: the impact of urban air pollution - a review.

This review examines the available information relating to the ingress of external pollutants into naturally ventilated buildings. It is part of a project whose longer term aim is to provide guidance on ventilation strategies for naturally ventilated buildings in polluted urban areas. The purpose of the review is to guide this project. It covers current ventilation strategies, existing measurements of internal/external pollution levels, urban air quality and long term air quality strategies, building ventilation and the dispersion of pollutants around buildings as they affect the ingress of pollutants.

At present, there is no formal advice on ventilation strategies to minimise the ingress of pollutants into buildings located in urban areas. The use of natural ventilation for buildings in such areas is to some extent affected by this deficiency and there is a tendency to prefer forced ventilation as an 'improved' option. In practice this need not be so.

Adequate guidance cannot be developed without an understanding of.

• Typical pollutants, their sources, how they disperse in urban areas and the concentration patterns produced on building surfaces in urban areas.
• Surface pressures on buildings, ventilation and infiltration processes as experienced by a building in an urban area.
• The occurrence of common areas of high pollutant concentrations and surface pressures on buildings.
• The relationship between the indoor and outdoor pollutant levels.

Generally there are significant information deficiencies in all these areas for the present application. Part of this is due to the multi-disciplinary nature of the application, for which none of these fields has a specific remit. For example, there are no identical experiments measuring both pollutant concentrations and wind pressures on the surfaces of buildings. The two specialisms are quite separate and have little intercommunication. Similarly, the problems of internal and external pollution levels tend to be considered separately, with little intercommunication. The review confirms the need for the investigatory part of the project, which is to monitor internal/external pollution levels and carry out a common experiment looking at pressures and concentrations on the surfaces of buildings in urban arrays.