DR E. GOOSEY
Clean energy, clean air, clean vehicles, clean fuel, clean air zones, and clean streets are just some of the instances where the word clean has been used to imply environmental impact reductions.
As a scientific reference ‘clean’ is subjective. Yet many publications can be seen to include the word clean without a proper reference point, definition or quantification being applied.
The term is ambiguous due to its universal use across many subjects and platforms, each with an individually derived definition. For example, the term clean, medically, is often referred to as a patient with a history of substance abuse who is no longer being exposed to such substances. This terminology is absolute, like the flip of a coin; the coin cannot possibly land on both sides, so therefore an individual is either clean or not. The same is not true for the food and sanitation industry. A surface can be deemed ‘clean’ if the microbial count is below a given threshold, but it does not have to be zero. Furthermore, the use of the term ‘clean’ for air may embrace many variables that need to be considered. For example, does this include microbes, man-made pollutants, vehicle emissions and particulates?
The word clean has become ubiquitous when trying to convey information to the public. Its concept is universally understood, making it a prime target for describing improvements in, for example, electricity production, household chemical substances, and government targets. But, it can often be adopted by scientists and stakeholders as an easy statement, which is hollow without a clear definition.
What do we really mean by the word ‘clean’ for an EV and the associated batteries?
As demonstrated herein, there are many interpretations of the term ‘clean’ that impact upon EVs and EV batteries. For the electric vehicle and associated industries and sectors, the word clean is used a lot. Beginning with the production of batteries, Amnesty International refer to the ‘cleaning’ of batteries to include both environmental and societal initiatives, reducing environmental impacts of raw material production, and improving the management and treatment of the individual people who carry out the labour.  In this context, clean is thus referred to as an elimination of human rights abuses, alongside use of environmentally responsible operations.
The Clean Vehicles Directive from the European Commission (2009/33/EC) was developed to promote clean and energy-efficient road transport vehicles in public procurement tenders. The terminology of clean being used by this Directive is not consistent and is dependent upon the vehicle being light-duty or heavy-duty. With reference to a clean light duty vehicle, the understanding is based on a calculation (defined in the Directive) of energy consumption, carbon dioxide production, NOx production, non-methane hydrocarbons and particulate matter. However, no thresholds were introduced within the Directive, so there is limited comparability between how the Directive was to be transcribed into local legislation. Plus, this Directive included a monetization calculation, which has been known to favour diesel vehicles because of their fuel efficiency, and unfortunately ignores the impact of NOx production in the final rating. A review  of the Directive in 2015 highlighted multiple problems which have resulted in the very limited success of the Directive in terms of producing a controlled response or conducting ‘clean’ procurement.
The UK has a ‘Clean Air Strategy’  which tries to address the most impactful sources of air pollution. The reference to ‘clean air’ is dependent upon the industry, or sector, being addressed under this strategy and includes ammonia from farming, but also sulphur dioxide, fine particulate matter (PM2.5), and non-methane volatile organic compounds from home fires, for example. However, unlike the Clean Vehicles Directive, the Clean Air Strategy includes reduction targets set by an international agreement to reduce the levels of five of the most impactful pollutants, along with setting defined reduction goals for other pollutants associated with public exposure.
Whilst the ‘clean air strategy’ envelopes a plethora of pollutants and emissions, the UK Government’s ‘Clean Growth Strategy’ is aligned with cutting greenhouse gas (GHG) emissions (the calculation of carbon dioxide equivalent used to reflect all GHGs). However, the strategy brings together multiple policies and proposals to reduce emissions, each of which has its own objectives and determination of the ‘clean’ thresholds. It is within this strategy that the government aims for clean growth – delivering increased economic growth with a decrease in emissions productions.
It is clear that the term clean has been adopted for use, much in the same way that ‘green’ or ‘eco’ have been in the past. The exact definition is dependent upon the user and the application, allowing the term to be used to reflect sustainable improvements made by any industry or individual. We must be careful when this word is used to describe sustainable developments achieved. Clean has been used to describe product or process developments which have achieved improvements in sustainability goals. The word also gives the impression that the product or process is now “clean” – i.e. void of any nasty emissions or impacts. In the majority of uses, this is simply not the case.
We should be wary of hiding behind this word (and many similar ones) when highlighting sustainability improvements achieved as, to a wider audience including the public and consumer market, these improvements can appear to be more significant and impactful than they actually are.
 Amnesty International, 2019. Amnesty challenges industry leaders to clean up their batteries. Published online: 21/03/2019, and available at: https://www.amnesty.org/en/latest/news/2019/03/amnesty-challenges-industry-leaders-to-clean-up-their-batteries/
 Brannigan et al. 2015. Evaluation of Directive 2009/33/EC. Final Report MOVE/A3/119-2013 Lot No 5 available online: https://ec.europa.eu/transport/sites/transport/files/facts-fundings/evaluations/doc/2015-09-21-ex-post-evaluation-directive-2009-33-ec.pdf
 UK Government, 2019. Policy Paper; clean air strategy 2019: executive summary. Published 14/01/2019. Accessed online 24/09/19, at: www.gov.uk/government/publications/clean-air-strategy-2019/clean-air-strategy-2019-executive-summary