Urban Air Pollution More Likely To Be Caused by Brake Dust Than Diesel Fuel: Study

Researchers are calling for improved emission regulations, after the findings of a new study confirmed that dust created by car brakes wearing down may contribute more to air pollution and lung damage than diesel exhaust.

According to the World Health Organization, air pollution is the leading environmental risk factor worldwide, contributing to an estimated 7 million premature deaths each year.

One key air pollutant is particulate matter, which consists of tiny particles and liquid droplets suspended in the air. Particulate matter with a diameter of less than 2.5 micrometers (PM2.5) can even affect the lungs, and is linked to significant health risks.

Major sources of PM2.5 in urban areas are cars and other vehicles. While exhaust emissions have been the focus of extensive research, leading to legislation aimed at reducing their effects, “non-exhaust emissions” from dust generated by the wear of roads, tires and brakes has been left largely unstudied and unregulated.

In a new report published in the journal Particle and Fibre Toxicology on February 13, researchers from the University of Southampton in the United Kingdom highlighted an urgent need to regulate non-exhaust emissions, after finding that particulate matter from brake wear may cause more air-pollution-related diseases than diesel exhaust.

The research team, led by James Parkin, grew cell cultures in a lab to mimic the lung lining and exposed them to brake dust and diesel exhaust.

Researchers discovered that brake dust was significantly more harmful to cells than diesel exhaust, based on multiple measures linked to lung diseases, such as cancer and asthma. Dust from copper-enriched and ceramic brake pads proved to be the most damaging.

The study tested brake dust from various pad types and found that dust from non-asbestos organic (NAO) pads, which are commonly used in vehicles, had high copper content and was the most toxic to lung cells, showing links to diseases like asthma, lung fibrosis and cancer.

Copper was found to penetrate lung cells and was consistently identified as a key contributor to the harmful properties of brake dust. Removing copper from brake dust reduced the toxic effects.

The study’s results emphasized the need for regulations that target non-exhaust particulate matter emissions.

In addition, the research team suggested that reformulating brake pads to reduce copper content and wear rates would help lower overall exposure to toxic brake emissions.

Health Risks Associated with Particulate Matter

Numerous studies have identified particulate matter and air pollution as posing severe risks to human health.

A study conducted by researchers in California found that pregnant women exposed to particulate matter from air pollution during their second trimester have an increased risk of preterm birth, which poses significant risks to the unborn child. For every 25% increase in pollutant exposure, there was a 15% increase in the likelihood of preterm birth.

Earlier this year, researchers found that 70% of lung deposits affected by particulate matter exposure came from air pollution caused by traffic, warning that traffic emissions can lead to high levels of the byproduct and carbon settling in the lungs of residents in large urban areas.

Another study indicated that childhood exposure to lead pollution from gasoline exhaust may have contributed to more than 150 million mental health diagnoses in the U.S., including higher rates of depression, anxiety, ADHD and other conditions.