Proc. 14 th International Clean Air & Environment Conference, Melbourne, 18–21 October 1998: Clean Air Society of Australia & New Zealand. pp 331–336 THE IMPACT OF URBAN DEVELOPMENT ON AIR QUALITY AND ENERGY USE P.C. Manins 1 , M.E. Cope 1 , P.J. Hurley 1 , P.W. Newton 2 , N.C. Smith 2 and L.O. Marquez 2 1 CSIRO Atmospheric Research, PMB 1, Aspendale 3195, Australia 2 CSIRO Building, Construction and Engineering, PO Box 56, Highett 3190, Australia Summary Melbourne has been used as a case study to investigate the effects of six alternative urban forms on air quality. The forms are Dispersed City, Compact City, Corridor City, Multi-Nodal City, Fringe-Development City and 'Business-As-Usual' City. We took 1991 as the base year, using emissions, population and transport data supplied by EPA Victoria. We specified changes in activities for each alternative development to the year 2011. We used an integrated landuse-transport optimisation model (Topaz 2000) to predict the changed emissions for each scenario. A coupled 3-D meteorological model (LADM) and photochemical airshed model (extended CIT model) were used to predict the hour by hour air quality conditions on an adverse winter day and an adverse summer day. For the modelled cases we found: Photochemical Smog. The exposure levels show a 55% improvement from base year for the Corridor City, compared with a 71% worsening for Business as Usual. Particulate Pollution. With particulate build up, there would be an improvement of 14% for the Corridor City and a worsening by 61% for Business as Usual compared to the base case. Exposure in the Compact City is, for the given emission load, substantially worse than in any other. Keywords: Urban form, modelling air quality, pollution exposure, particulate pollution, photochemical smog, landuse-transport modelling. 1. Introduction What alternatives are there for the “shape” or structure of our cities? The most prominent archetypal alternatives are illustrated in Figure 1. These may be described as follows (after: Pressman, 1985; Minnery, 1992; Newton, 1997) • Business As Usual – extrapolation of current patterns into the future; • Compact City – increased population and density of an inner group of suburbs; • Edge City – increased population, housing densities and employment at selected nodes within the city; increased investment in orbital freeways linking the edge cities; • Corridor City – a focus of growth along linear corridors emanating from the CBD and supported by upgraded public transit infrastructure; • Fringe City – additional growth predominantly on the fringe of the city; and • Ultra City – additional growth primarily in provin- cial cities within 100 km of the principal (capital) city and linked by high speed rail transport. All cities, irrespective of their geographic location, can be re-shaped to generate greater liveability. Which of the above archetypal urban forms is most desirable, from an environmental perspective? Research undertaken for the recently completed Inquiry into Urban Air Quality in Australian Cities (Newton, 1997) attempted to explore, for the first time, the nexus between urban form and three key dimensions of the environment, namely: ambient air quality, green- house gas emissions, and transport energy use. This new research employed integrated landuse- transport-environment (LUTE) modelling to assess the ‘performance’ of Melbourne in the year 2011 (from an environmental perspective) in the context of the above six contrasting archetypal urban development scenarios. 2. The Environmental Performance Appraisal Model Since urban development and urban form can be characterised by changes in land use, this work used the TOPAZ 2000 landuse-transport model (considerably enhanced from Brotchie et al. 1980) (see Figure 2) integ- rated with prognostic airshed modelling (see Figure 3) as the tool for evaluating the impact on air quality of different urban growth scenarios.