The subject of air pollution has recently come back onto the public agenda. This has been highlighted particularly by the Volkswagen emissions scandal, which has shown how vehicle manufacturers can defy the spirit of the law and, in the case of Volkswagen, even allegedly break the letter of the law, with a consequence of much higher emissions of air pollutants than the regulatory limits intended. It is therefore perhaps unsurprising that road traffic immediately comes into the public mind when air pollutants are mentioned, although there are many circumstances where road vehicles are not the main sources of pollutants affecting the local atmosphere. However, what is often ignored is the fact that road traffic causes pollution of water and soil, as well as creating noise, which can have adverse effects on human health.
The majority of vehicles currently on the road burn fossil fuels in an internal combustion engine, but this will not always be so. Already there are significant numbers of hybrid vehicles on the road that combine an electric motor with an internal combustion engine. Battery electric vehicles, which use solely electric power, are also now available, although sales in most parts of the world remain modest. There is also the option of using fuel cells with fuels such as hydrogen to generate electricity on board in order to power the vehicle. Although in some jurisdictions electric vehicles are referred to as ‘zero-emission vehicles’, this ignores the fact that pollution is created by the generation of electricity, and there are also environmental costs to the production of batteries and the final disposal of the vehicle. Such external implications of vehicles can be compared through the use of life-cycle analysis, which takes account of the implications of the vehicle right through from the extraction of raw materials for vehicle construction and the production of fuel to the pollutant emissions caused during operation.
In order to set the context for the subsequent chapters, the first chapter by Athanasios Tsolakis and co-authors describes road vehicle technologies and fuels, starting with the present, but also looking forwards to the future. The next two chapters deal with emissions to the atmosphere, with gaseous and particulate greenhouse emissions considered by Magin Lapuerta and co-authors and locally acting (i.e. toxic) air pollutant emissions considered by Qingyang Liu and Jamie Schauer. One important point that is made clearly in the latter chapter is that non-exhaust emissions of particles from the wear of tyres, brakes and the road surface are unregulated and are typically now larger sources of particle emissions than the exhaust of the vehicle. Such particles also arise from hybrid and electric vehicles.
The next two chapters deal with specific environmental and human health effects of road vehicles. Ashantha Goonetilleke and co-authors describe the water and soil pollution implications of road traffic, while the cardiovascular health effects of road traffic noise are the subject of the following chapter by Anna Hansell and co-authors. Both are shown to cause significant impacts, which are frequently given inadequate consideration in relation to road traffic.
Two further chapters look to the future. Billy Wu and Gregory Offer describe the environmental impacts of hybrid and electric vehicles. While superficially attractive, such vehicles can cause substantial pollutant emissions, although not necessarily at the point of operation. Hydrogen has frequently been mooted as a possibly cleaner fuel for road transport, which would most likely be used in fuel cells rather than directly combusted. A major benefit of this is likely to be in reducing greenhouse gas emissions, provided that the hydrogen can be generated using electricity from renewable sources. Angelina Ambrose and co-authors take an economic approach to evaluating the developmental implications for Malaysia of hydrogen use as a road transport fuel.
The final two chapters give further valuable perspectives, firstly on end-of-life vehicle recycling and secondly on life-cycle analysis of road vehicles. Jeongsoo Yu and co-authors provide case study information on the fate of end-of-life vehicle recycling in the Far East and show how well-intentioned legislation designed to protect the environment can have unintended consequences that are detrimental to the environment. As mentioned above, a complete evaluation of the impact of road vehicles can be conducted through life-cycle analysis; Michel Vedrenne and co-authors specify the principles of life-cycle analysis and give examples of real-world applications in comparing vehicles of different types.
We are pleased to have compiled a volume giving a very broad overview and perspective on the impacts of road vehicles on the environment. We believe that this will provide a valuable resource for students, practitioners and policymakers alike in seeking information on the key considerations associated with the use of vehicles upon our roads.
Ronald E. Hester
Roy M. Harrison