Relations between Energy Consumption and Air Quality in an Urban Environment: Spatial Scenarios of Emission Reduction

The aim of this work is to set up a method to estimate air emissions from energy consuming activities in an urban environment and to explore the effects of measures to minimize impact on air quality. 4 The main energetic activities that produce emissions in urban environments are transport, industrial processes and heating of buildings. The amount of a particular pollutant arising from a combustion process is estimated by the method of “emission factors”, that is, the emission is proportional to the “activity rate” of the process. The activity rate in transport is the number of kilometers covered by different kinds of motor vehicles and in the other combustion processes is the fuel (gas, gas oil, and oil) consumption. The emission factors used in this work are those of the EPA 1 and of CORINAIR 2 (transport). The input data needed for these evaluations are: fuel consumption and the number of kilometers covered by the vehicles in the area of interest. The method of “correlated variables” is used for spatial spreading of input data: it consists of attributing, to an aggregated value, the spatial distribution of the correlated variable. The distribution of occupied houses is used to spread fuel consumption for building heating in the household sector. All input data are distributed on a spatial grid to evaluate emissions for each pair of coordinates (i, j). Several measures can be hypothesized to reduce air pollution: substitution of energy sources; introduction of better technologies; and, in the case of transport, reduction of road traffic and an increase of public transport. These methods have been applied to the case of the city of Florence, Italy. It is a medium-large, historical city presenting acute episodes of air pollution mainly caused by CO, NOx, and VOC (as a precursor of O3). A number of measures have been hypothesized: substitution of fossil fuels with other less polluting fossil sources (liquid fuels with gas), substitution of residential gas furnaces with larger sized gas boilers, reduction in the number private cars and motorcycles and substitution by public transport, reduction of heavy transport and substitution of non renewable sources with renewable ones. The aim of these measures was a 10% reduction in pollutants