Electric Cars Are As Green As You Think And Don’t Produce More Polluting Particles

The war of words against EVs is hotting up, as I’ve mentioned before. Now the UK’s own Environment Minister George Eustice has waded in and amplified a common trope amongst electric vehicle haters – that they’re not really as green as they pretend to be. This is a huge surprise from someone who is supposed to be improving environmental conditions, particularly as he’s just plain wrong.

This argument revolves around the pollutants emitted by vehicles that don’t come out of the tailpipe. Although CO2 and related carbon-based gases are the global environmental menace responsible for global warming, in cities NOx and particulates are emerging as the major, and more immediate, health problem. This is why there has been a complete 180-degree shift on the merits of diesel engines. While these typically produce less CO2 than gasoline, they are much worse for NOx and particulates. For this reason, city clean air zones tend to require diesel cars to be much more recently manufactured to meet standards than fossil fuel cars.

It is true that there are environmental impacts of vehicle usage beyond the tailpipe (and I don’t mean the impact of electricity generation, which I’ve tackled before). Tires shed rubber as they wear down, brake pads create dust as they rub against discs, and roads are damaged as vehicles drive over them. However, if you listen to what Eustice said (alongside numerous keyboard warriors on social media), you will think this is a massive hidden pollution, in the same way as Dieselgate hid the pollution of diesels.

However, a 2019 report from the UK government’s Department for Environment, Food and Rural Affairs (aka Defra) argued that while these three elements (brake wear, tire wear, road surface wear) contribute 60% of PM2.5 and 73% of PM10 emissions, the overall contribution to UK emissions of these two pollutants is just 7.4% and 8.5% respectively. If you’re not clear on what PM2.5 and PM10 are, these are polluting particles of 2.5 microns (PM2.5) width or less, or 10 microns or less (PM10). They are the tiny dust fragments that contribute badly to respiratory conditions, such as asthma, and have now been conclusively cited as causing the death of South London schoolgirl Ella Kissi-Debrah. At this point, it should be underlined that the person ultimately in charge of Defra is George Eustice, a job he has held for a couple of years now. So he really should have read this report.

The argument from the article quoting Eustice is that EVs are heavier, so they produce more brake, tire, and road dust. It is true that EVs are heavier – mostly. If you take a car that has both fossil fuel and electric variants, the latter will be a few hundred kilograms more mass. Here are a few examples. The BMW X3 SUV weighs up to 2,095kg, whereas the iX3 electric variant is a much portlier 2,260kg, which is at least 165kg more. The popular Hyundai Kona weighs up to 1,556kg in fossil fuel form, but the electric version weighs up to 1,743kg.

However, a pure battery-electric vehicle can be manufactured to mitigate this. For example, the Tesla Model X weighs 2,533kg, but an equivalent fossil fuel SUV is the Range Rover, and in the past that could be up to 2,673kg, although the most recent model is lighter. The Porsche Cayenne weighs up to 2,565kg. So if you’re worried about heavy vehicles, start with SUVs and then think about EVs.

That said, the extra weight does mean there will be a little more tire dust and road damage from EVs – but hardly a huge amount more, if the BMW iX3 and Hyundai Kona Electric are anything to go by. If it’s a pure straight-line formula, the iX3 is just 7.9% heavier than the X3, and the Kona Electric just 12% heavier, so only this much more dust will be produced. However, this could easily be mitigated by the fact that the brake dust produced by EVs is almost non-existent, not greater than fossil fuel vehicles at all.

The biggest problem here is that Eustice (and the badly researched article reporting on his words) fails to understand that despite the extra weight of EVs, the way they work means that they tend to not use their friction brakes very often during everyday use. Any EV driver will tell you that their cars do something called “regenerative braking”, where the motor runs in reverse when you take your foot off the accelerator, and more so when you hit the brake. This means that before the brake pads are engaged, as much energy is recouped as possible to slow the car down and recharge the batteries. This is why hybrids are more economical than non-hybrids, because they also use this system.

There are reports of eight-year-old Teslas not needing new brake pads in their entire lifetime. If you look at the disc brakes of EVs parked on the street, you’ll see the metal discs are often rusty, because during city use, they are so rarely engaged. In fact, there are recommendations that EV users occasionally find a spot to do some safe hard braking to clear this rust off to maintain optimal functioning of disc brakes, should they need to be used in an emergency.

EVs use their friction brakes so little that VW has even started installing drum brakes on the rear axles of its electric vehicles. The VW ID. cars are all rear-wheel-drive (or all-wheel-drive) so the rear axles are mostly braked via motor regeneration. VW is now putting an advanced drum brake here that is meant to last the life of the car, never needing new pads. Since drum brakes are enclosed, even when used they won’t release dust into the environment. The impact of regenerative braking was even cited in the aforementioned Defra report, which Eustice clearly hasn’t read.

So are EVs less green than we think when it comes to this kind of environmental pollution? No. The chances are they are also greener in this respect than fossil fuel vehicles. Add to that the huge benefit to CO2 emissions, whatever the electricity grid feeding them (even China’s or Australia’s), and EVs remain the most environmentally friendly vehicle choice there is. The UK’s Environment Minister George Eustice should know that and get behind it rather than contribute to the proliferation of misinformation. After all, isn’t that supposed to be his job?