Bigger batteries in EVs could lead to colossal boost in particulate emissions—from tires, study suggests

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Increasing the size of EV battery packs can increase range, but a new study suggests that it may also result in a significant rise in particulate emissions from the tires.

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Emissions Analytics, an independent emissions testing firm based in the United Kingdom conducted the research. It first raised the alarm in 2020, when it published a study that found tire-wear particulate emissions were a thousand times worse off than tailpipe emissions.

According to Green Car Congress, the research was intended to accurately measure the worst-case tire emissions under legal driving conditions. The most recent research is based on a more comprehensive analysis done in the interim, which covered a broader spectrum of driving conditions. Emissions Analytics has also conducted chemical analysis on loads of new tires, even collaborating with the United Kingdom’s National Physical Laboratory to accurately measure chemical composition uncertainties.

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The end result? According to Emissions Analytics, under normal driving conditions, tire-wear particulate emissions are 1,850 times higher than tailpipe particulate emissions. As per Emissions Analytics, “The fundamental trends that drive this ratio are: tailpipe particulate emissions are much lower on new cars, and tire wear emissions increase with vehicle mass and aggressiveness of driving style.” This is not good news for bigger electric car battery packs which add a significant amount of weight. 

This is bad news for larger electric vehicle battery packs, which add a substantial amount of weight. They concluded that if all other things are equal, 1/2 a  metric ton of battery weight can lead to tire emissions that are 400 times more than real-world tailpipe emissions. 

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The organization did point out that tailpipe emissions are suspended in the air for a period of time, negatively impacting air quality, whereas tire emissions typically end up in water and soil. According to Emissions Analytics, approximately 11% of the mass of tire emissions is narrower than 2.5 microns in diameter. That is the limit for airborne particulates that can lead to respiratory problems.

Tailpipe emissions continue to be a major concern, especially in regard to climate change. However, as new vehicles become more efficient and electrical vehicles take a greater share of the fleet, the impact of tire emissions on the environment must be addressed. A 2021 study discovered that, in addition to particulates, tires were a major contributor to microplastic pollution.

As a result, some inventors, such as Dyson researchers, are devising novel ways to assist vehicles in cleaning themselves as they travel to reduce particulate emissions. Regulators must also address tire recycling so that used tires do not pollute the environment during disposal.