Brake Dust: Allergy and Asthma Cause ?

Dust Allergy

Brake and clutch dust coats every highway: could it be an unseen contributing cause of asthma and allergy?

Brake dust is a fine powder residue of invisible particles, from brake pads and shoes, which grind against rotors and drums. Clutch dust is generated as surfaces of clutch discs slip during the clutch lockup process. Below the bell housing, a vent hole allows the powder to trickle out.

With millions of vehicles on the road, these particles are a significant contributor to ambient air particulate, maybe 1-2%. But on the highway, right at the level where air is being forced into auto cabins, they are much denser.

What is this powder made of?

brakes Analyses of brake particulate yield less than 1% asbestos, mostly short chrysotile fibers below 1 micron long. Scientific studies have focused mostly on mesothelioma, finding no strong correlation between that asbestos related illness and brake shop employment. Little attention has been given to the other health effects, such as allergies to the dust we drive in.

Asbestos has long been used in brake pads and linings, clutch facings and gaskets. Millions of brakes and clutches installed on vehicles still contain asbestos, no longer used in new production.

Modern pads can be made of carbon fibers, glass fibers, mineral wool, metal filings, aramid fibers, ceramic fibers, silica, and adhesive. Brake adhesive is highly corrosive, acidic, and adheres to the metal filings. This makes the dust stick to wheels, annoying car buffs. It takes special detergent to remove brake powder from wheels: what does it do in our lungs?

When so much attention is given to, fo example, dust mite allergens, why are there so few studies done on road dust and allergies?

Many brakes are driven beyond proper replacement intervals, scraping metal rivets against rotors and drums, grinding fine metal particles off. These join metal filings from u-joints, loose suspension parts, and rubbing, rusting mufflers, in the dust lying on the roadway.

Fine metal wear particles from internal engine parts, in vehicle exhaust, contain toxic heavy metals. Nickel, Mercury, Lead, and Cadmium are known toxins among others.

Road Dust: Potential Allergens

Researchers disagree about the health risks from exposure to brake dust. Exposure to silica dust can cause silicosis, a lung disease which gradually reduces lung capacity. Other non-asbestos fibers, when inhaled, can cause similar diseases of the lung.

Experts point out that in recent years, while allergy and asthma have increased dramatically, all markers of air pollution have declined. But these markers stop measuring particulate at 2.5 microns, above the invisible sub-micron level.

I think this partly explains how children living near freeways can have higher asthma/allergy rates in "cleaner" air. Of course, what healthy person would live near a freeway if they didn't have to: socioeconomic factors play a role in these statistics.

What concerns us here is the allergy causing risk we may be taking, breathing road dust while driving on the highway, whether we live close or not.

A chronic toxic exposure creates a mechanism of avoidance of the toxin. Allergy and asthma can be understood as our body's way of communicating its dislike for the environment.

Allergies are not a random accident, they are a natural response to unhealthy conditions: industrial disease. The automobile has distributed once localized pollutants of the dusty 19th century factory to every hillside and valley, and added new variants along the way. Dust allergy is the logical outcome.

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