Road transport induced GHG emissions calculation for urban transportation networks: The case of Athens and Thessaloniki in Greece

Abstract

The natural greenhouse effect of the Earth’s system has long been affected among others by the excessive use of private vehicles all over the world. This has led to the fastest humanly recorded change of climate, whose implications have already started impacting human systems and assets. In an effort to gain a clear understanding of the amount of Greenhouse Gases (GHG) emitted in Greece, this paper maps carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) pollutants in the two largest cities of the country, namely Athens and Thessaloniki. In the case of Athens, the hourly volume data measured by inductive loop detectors installed at 557 locations across the city were imported to a large-scale transportation model of the city, along with the vehicle fleet composition and a detailed representation of the urban and regional road network. The outputted hourly vehicle volumes, the average speed and the vehicle fleet composition of the 81.880 links of the network for a typical weekday of October 2010 were then inputted to COPERT Micro for the calculation of the hourly and daily emissions. Afterwards, the emission values from COPERT Micro were imported to a GIS grid in order to visualize how the GHG emissions are distributed throughout the city. A similar approach was followed in the case of Thessaloniki. The simulated network consisted of 137.938 links and the emissions’ calculations were performed for a typical weekday of November 2014. In both case studies, the results at link level revealed the local pollution hot-spots and the high-emission links, which usually lie along the main urban highways. Passenger cars and light duty vehicles are the main vehicle categories contributing in GHG emissions, along with two-wheel vehicles, which strongly affect CH4 emissions. Thus, apart from alleviating the traffic in the large arterials, the application of stricter policies and cleaner technologies in these vehicle categories should be also examined, if the country needs to meet its Kyoto targets.