In a discovery that could have chilling implications for public health, scientists have found that air pollution from auto traffic can adhere to human red blood cells and circulate throughout the body.
What’s happening?
Researchers found that inhaling air by the side of a busy road can introduce pollution particles into the bloodstream. In some cases, the particles continue circulating throughout the body even after a person moves to a less polluted location, according to a press release from Lancaster University.
To test how auto pollution enters the bloodstream, scientists at Lancaster University and Queen Mary University of London had 12 healthy adult volunteers spend four hours in a well-ventilated office building, followed by one hour near a busy London road. The participants then returned to the office building, where they stayed for another hour.
The volunteers carried devices called aethalometers to test the levels of air pollution in both places. They also provided blood samples each time they changed locations.
The results, published in ERJ Open Research, showed that the level of particulate matter in people’s blood increased after they spent time by the road. And the more pollution individuals detected on their aethalometers, the more particulate matter appeared in their blood samples.
“Exposure to traffic-derived particulate air pollution has been linked statistically with a range of diseases, including blood clots, heart attacks, lung cancer, and Alzheimer’s disease,” said Professor Barbara Maher of Lancaster University. “It’s been assumed, but never shown before, that the smallest air pollution particles can escape from the lungs and into the bloodstream and then get transported all around the body.”
However, there was one silver lining. The researchers completed the same experiment again, but this time, they had the participants wear FFP2 masks, which led to a significant reduction in the amount of pollution in people’s blood.
Why is auto pollution important?
Cars contribute to air pollution in several ways. Gas-powered cars emit pollution from their tailpipes, and all cars spew fine particulate matter as their brakes and tires wear down.
Breathing dirty air can increase people’s susceptibility to diseases, including heart disease, asthma, and cancer, leading to air pollution’s reputation as a “silent killer.”
The researchers noted that pollution particles have been found in people’s brains and hearts, and their study provides evidence on how the particles got there. It suggests that air pollution is dangerous to a number of organs, not just the lungs.
“Our work shows how important it is for human exposure to traffic-derived air pollution particles to be reduced, as a matter of urgency, especially for vulnerable people like young children, pregnant women, and the elderly,” Maher told Lancaster University.
What’s being done about auto pollution?
The increased adoption of electric vehicles is one of the most surefire ways that communities can reduce pollution from cars. In 2024, electric vehicles made up more than 20% of the global auto market share, according to the Alliance for Automotive Innovation — up from a 4.6% market share in 2020. This suggests that the transition to an all-electric future is already well underway.
Using public transit or traveling by bicycle can also reduce pollution from worn-out car tires. And, if you happen to find yourself stuck breathing air by the side of the road for an extended period of time, wearing a face mask can limit your exposure to harmful particles, as the researchers showed.
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