Environmental Impacts of Road Vehicles

Recent media coverage in the wake of the vehicle emission testing scandal and reports of poor air quality across the UK, particularly in London, have drawn renewed attention to pollution from road transport. Last year, the Environmental Chemistry Group hosted a oneday symposium (“Inside the Engine”, see ECG Bulletin, July 2017 https://www.envchemgroup.com/2017-inside -the-engine.html) illustrating the main environmental issues arising from road pollution as well as its detrimental effects on human health. This book, organised in nine selfcontained chapters, provides an account of the complexity of this environmental issue. It first focuses on the two main vehicle technologies currently used (petrol and diesel), and their atmospheric implications in terms of greenhouse gas emissions (CO2, CH4, N2O) and urban air quality (nitrogen oxides, ozone, particulate matter). It then expands on the impact of these vehicles on the environments beside roads, with a very clear description of the wash-off of pollutants from roads caused by rain, the subsequent contamination of soils and waters and the potential uptake of toxic substances (e.g. trace metals) by plants. Later chapters in the book focus on the development and assessment of alternative technologies to fossil fuels. A recurring theme throughout the book is the importance of life cycle analysis for all vehicle technologies, old and new. A number of examples are provided to illustrate how the assessment of the environmental impact of vehicles would be incomplete without taking into account both direct (e.g. tailpipe emissions) and indirect (e.g. fuel extraction, vehicle disposal) processes. The importance of this “well-to-wheel” analysis is evident when comparing alternative technologies with fossil fuels; in the case of biofuels, any reduction in CO2 resulting from not burning fossil fuels may be partially offset by excess emissions of other powerful greenhouse gases (methane and N2O) from growing crops to produce biofuels. This type of assessment is even more critical for battery-powered electric vehicles, as the environmental benefits depend crucially on how electricity is generated. The chapter covering the impact of noise from road transport on human health was most interesting to me: this area is not as well-studied as other aspects of road pollution, and suffers from the absence of a “noise observation” network akin to those for local air quality. Nonetheless, current evidence seems to indicate that traffic noise may play a role in the development of hypertension and ischemic heart disease. Food for thought abounds in the future scenarios described in the book: for instance, as electric vehicles are projected to become more widespread in the near future, new challenges will emerge in recycling large numbers of lithium-ion batteries when these vehicles arrive at the end of their life cycles. At the same time, articulate matter from tyre and brake wearand-tear will still be an environmental issue regardless of the fuel used to power vehicles. It is evident that, even when our dependence on fossil fuels for transport is a distant memory, our efforts in safeguarding the environment will be far from over. -- Valerio Ferracci (Cranfield University)
The advent of highly sensitive GC detectors in the late 1950s/early 1960s provided the first means of measuring road vehicle emissions, trapped in the naturally occurring ‘blue smog’ layer that vapourised from eucalyptus trees in the Los Angeles basin. A similar UK test bed was Manchester’s Trafford Park industrial area, specifically in the early 1960s Friday night “rush hour”, where traffic was often at a standstill for long periods. It was discovered that the range and concentrations of hydrocarbons in the Manchester smog echoed those reported in California. Detection and identification proved to be the simplest element; the most difficult part was deriving accurate quantification. This Volume 44 of the “Issues in Environmental Science and Technology” series would appear to be timely, coinciding with the UK Government’s announcement of the end of the combustion engine in 2040 to be replaced by electrically driven vehicles. However, it largely concentrates on water, soil and noise pollution, rather than those issues more currently in the news. Although each individual chapter is well researched, and fully cross-referenced, the overall coverage is very limited.Each chapter is effectively a monogram, with minimal or zero overall continuity between the subjects. Air pollution is stated to be the leading health risk from road vehicles. One report (a 2010 Health Effects Institute) suggests that 3.2 million premature deaths are caused by outdoor air pollution. From this, and similar reports, a constantly quoted and alarming “30,000 premature deaths are caused by diesel particulate matter” has been stated as a fact in all UK news features. From a journalistic viewpoint, since there is no headline in optimism, perhaps this is no surprise. Regrettably, this massively misquoted statistic is now  almost) universally believed by all, particularly by politicians able to legislate. If only they were able to read, learn and properly analyse all the statistics in all the reports, the outcome would be different. To say that the evidence for cause of death by air pollution is minimal is a gross understatement, but a rather more provable interpretation is that the average length of human life in the UK is actually reduced by 3 min. As would be expected in looking at future trends, there is an emphasis on the replacement of internal combustion engines by electric vehicles. The simple facts are: CO2 emissions would be reduced by a factor of 2.5 (i.e. engine efficiency 16–18%, gas-fuelled power stations 50%); there is a huge overall reduction of carbon particulates, NOx and other noxious gases. The speed of changeover will evolve around battery technology, not the car body, but over 2000 moving parts per vehicle are eliminated; engine noise is greatly reduced and so on. A useful subject would have been the current limitations preventing an early rapid changeover, the current lack of supporting infrastructure (eventually to be overcome by road-installed induction pads coupled with very fast-charging batteries), and the lack of both battery manufacture and automotive large-scale assembly lines (the six-tenths rule). Unfortunately, Volume 44 represents a missed opportunity to at least refer to the massive current amount of work now in research phases by both large and small automotive companies. The future is unquestionably electric vehicles, but development to a mainstream position will require an immense investment in infrastructure, both public and private; now that will make a very lively discussion! -- Ken Jones * Chromatographia (2017) 80:1819–1820 *