ASSESSING THE IMPACT OF HIGH-RISE BUILDING DENSITY ON URBAN CFC EMISSIONS: A SPATIAL ANALYSIS APPROACH

Abstract

This study has examined the complex relationships between the extent of high-rise construction and the emission of chlorofluorocarbons (CFC) among the megacities of Pakistan using a multifaceted spatial analytical orientation. The case studies incorporated the cities of Karachi, Lahore, and Islamabad which have been experiencing unprecedented growth in vertical construction and the rising concomitant environmental challenges that this growth entails. Using CFC data, collected from the Pakistan Environmental Protection Agency (EPA) and from the field, the researchers mapped the distribution of high-rise buildings using Geo-Spatial Information Systems (GIS) and then integrated this data with the CFC emission data. The use of the Moran’s I coefficient test demonstrated that CFC emissions were appreciably clustered in areas of high-rise construction. The use of buffer zone analysis confirmed the emissions were biased in a number of directions and in particular from the areas of dense high-rise construction, while regression analysis demonstrated significant and positive relationships between the several measures of building density and the CFC emissions. It was determined and then quite clearly explained that among the areas having high emission of CFC (especially in the refrigeration and air conditioning system frequently observed as housed in the upper floors of commercial high-rise buildings), increasing the floor area ratio and the building height contributed in a major way. The predicted spatial distributions were confirmed through a number of field checks, and the variability in meteorological conditions were used to explain the observed results. The study conclusively demonstrated the vertical urbanization of major urban areas in Pakistan and its unsustainable environmental consequences. The results provided a number of planning recommendations that, if implemented, will assist in the reduction of CFC emissions from the urban planning of vertical megacities.