## 1 Introduction  
Air quality levels across Europe remain problematic, especially in urban regions [1]. These are found to be hotspots for nitrogen oxides (NO\({}_{\rm X}\)) and particulate matter (PM), for which road transport has a substantial contribution [2]. In the light of mitigating local air quality levels, pollutant emissions from both passenger cars, light-commercial, and heavy-duty vehicles have been regulated by the so-called Euro emission standards [3]. For cars, these progressive reduction targets have proven their efficacy for bringing down the emissions of exhausted PM, carbon monoxide (CO), unburned hydrocarbons (HC), and petrol NO\({}_{\rm x}\). For diesel cars, however, substantial exceedances with the imposed NO\({}_{\rm x}\) limits are found. Evidence results from both rigorous chassis dynamometer testing [4; 5], real-world driving tests using portable emissions measurement systems (PEMS) [6; 7], and roadside remote sensing campaigns [8; 9]. For heavy-duty vehicles, which are no further discussed in the presented paper, substantial NO\({}_{\rm x}\) reductions for heavy-duty vehicles have been realized since Euro VI. As such, they produce only half the NO\({}_{\rm x}\) emissions compared to the average Euro 6 diesel car, when compared on a kilometer basis [10]. Concerning transport's impact on climate change, the European light-duty vehicle sector is imposed to a target for carbon dioxide (CO\({}_{2}\)) emissions. Therefore, each car manufacturer is required to obtain a corporate average fleet fuel economy of 95 g of CO\({}_{2}\) per kilometer by 2021, as described in Regulation (EC) 2009/443 [11]. Electric vehicles (EVs) are key assets in reaching this target, as they are given extra weight in the balance using so-called _super-credit factors_[12]. These allow EVs to count for more than one car in the fleet average calculation. An indirect effect of Regulation 443 is that EV-producing car manufacturers are less incentivized to lower the CO\({}_{2}\) emissions of their remaining conventional models, as electric vehicles bring down their fleet's average [13]. The importance of the 2021 and future CO\({}_{2}\) targets in Europe is strengthened by the 2015 Paris Agreement, in which the majority of the world's nations agreed to strictly reduce greenhouse gas emissions (GHG, represented by CO\({}_{2}\)-equivalent gasses), in order to keep the global temperature increase well below 2 \({}^{\circ}\)C, relative to pre-industrial levels [14]. Despite the current lack of a well-defined roadmap towards this goal, a net-zero GHG economy is required by 2050 or shortly after that [15]. For this reason, the European Union strives to a minimum GHG reduction by 60 percent for its transport sector by 2050, while its entire economy is bound to reduce its GHG contribution by 80 to 95 percent [16]. In the light of decarbonizing the light-duty fleet, electrification is believed to play a major role if the electricity production sector follows the same decarbonization trend. Notwithstanding, we see that EVs applied in Europe already produce less CO\({}_{2}\) than a diesel car of the same segment on a well-to-wheel basis, even when applying electricity from a coal-intensive production like in Poland [17]. Besides the CO\({}_{2}\) reduction potential, however, current battery technologies have a significant environmental impact when their manufacturing process is considered, and this is primarily due to mining practices [18]. This indicates the need for cleaner technologies and a ramping-up of recycling used batteries. Given an average lifetime of a battery applied in an automobile of ten years, a substantial stream of used batteries is yet to come. Moreover, second-life application in stationary power storage can extend the useful life of batteries significantly, indicating a further shift in time before recycling the current generation of batteries becomes economically viable.