ABSTRACT
Introduction Breaches of prescribed air quality standards in cities are frequently associated with the need to travel from residential suburban areas to city centres for business, shopping, entertainment and leisure facilities, universities and historical heritage sites. Although most European cities have a well-developed rail network, most commuter traffic is by motor vehicles, which concentrate pollutant emissions as they converge on, or diverge from, the city centre. Recently, the local authorities in the UK have started supporting the creation of new multi-storey residential developments within city centres, which will inevitably lead to the creation of deeper street canyons and a reduction of natural ventilation. The inhabitants of these new residences are likely to be subjected to higher pollutant concentrations, and for longer periods than the commuters, who spend more time in less-polluted suburbs.
