Study: Brake Dust More Harmful To Humans Than Diesel Emissions

A new study recently indicated that brake dust emitted by both EVs and ICE vehicles are much more harmful to human health than diesel emissions.

Though electric vehicles (EVs) are widely hailed by supporters as a key tool towards reducing global warming and making our air cleaner to breathe versus combustion (ICE) vehicles, they still emit certain types of emissions that are still very harmful to human health.

In fact, a new research published recently by University of Southampton suggests that brake dust, commonly emitted by both EVs and ICE vehicles, is much more toxic and definitely more harmful than breathing in heavy diesel smog.

The study also stresses EVs emit more brake dust per stop versus ICE counterparts due to their heavier weight, and that's despite their ability to use non-friction braking via e-motor 'regen'.

This is indeed a surprise, more so considering the perception that EVs rely heavily on regenerative braking (commonly called ‘regen’) from their e-motors that significantly reduces the use of traditional friction brakes.

However, EVs are also significantly heavier versus ICE (non-PHEV) counterparts. In other words, when frictions brakes are eventually applied in EVs, they tend to generate more brake dust per stop, says this new study.

Several types of brake pads were tested in said study, and it found non-asbestos organic pad types to be the most harmful - these caused the most lung inflammation.

A slew of emissions particulates from different types of brake pads were studied by scientists. Amongst the brake pad types tested included low-metallic, semi-metallic, non-asbestos organic, and hybrid ceramic types – all widely available in most EVs and ICE vehicles today.

Surprisingly, the non-asbestos organic pads tested stood out as they caused the most lung inflammation, thus making them more toxic than diesel emissions.  Initially developed to replace older pads containing asbestos, copper fibers, which improve thermal conductivity, substitute the asbestos instead.

Specifically, it's the copper dust emitted by these brake pad type that are very harmful. Like the asbestos they replace, copper dust are linked as causes for lung ailment like cancer and asthma.

However, like asbestos, which has proven links to causing lung disease, copper dust in these type of brake pads are also found to be linked to lung ailments like cancer, asthma and chronic pulmonary disease. More concerning too is the fact that this brake pad type is the most common type on sale due to their low cost, noise, and wear rate.

Up until this point, this type of emissions aren’t exactly regulated, but this will change next year (2026) as Euro 7 emissions standards are enforced. Part of this updated legislations is the inclusion of brake dust emissions limits, though this is likely to be policed across new cars, not parts available in existing ones.

Apart from which, there’s little regulation globally that governs non-tailpipe vehicle emissions, including from tyres – arguably another major source of harmful particles. Similarly, because of their heavier weight, EVs also tend to produce even more tyre pollution versus ICE vehicles.