Anticipated Effects of Gradual Replacement of Internal Combustion Engines with Electric Drives on Vehicle Exhaust Emissions in Prague

In a broader effort to explore the possibility of optimizing the deployment of electric drives to achieve the maximum benefit for air quality, this paper explores the patterns of deployment of electric drives in Prague, Czech Republic, and the air quality benefits of various patterns of electric drive usage to air quality. One of the benefits of introducing electric and hybrid-electric vehicles into the fleet is the reduction of exhaust and to a lesser extent evaporative emissions from vehicles powered by internal combustion engines. Such reductions are often based on "average" emissions rates of the regulated pollutants. In reality, electric vehicles are being introduced in a rather selective manner, with preference to low speed, short distance urban trips, due to energy storage limitations. As a coincidence, during such operating regimes, the internal combustion engines are at their worst not only in terms of efficiency and emissions of regulated pollutants, but, more importantly, in terms of the health effects caused by these emissions. Deployment of electric drive vehicles in congested urban areas, where it appears most advantageous technically and economically, is therefore expected to have relatively high benefits to human health due to reduced exhaust emissions. Current patterns of electric drive deployment therefore already appear to be close to optimal in terms of their benefits to air quality.