Breathing In Diesel Fumes Is Crippling Our Immune Systems

It's well established that breathing in diesel exhaust can have negative effects on our bodies. But beyond a tickling throat, studies have shown that these vehicle fumes may have wider-reaching health impacts, including disrupting our immune system and triggering inflammation.

Worldwide, exposure to the fine particulate matter in polluted air causes 7 million deaths every year, according to estimates from the World Health Organization. And more than 1 in 3 Americans lives in counties with unhealthy levels of air pollution, the American Lung Society reports.

These tiny particles can penetrate deep into the lungs and cardiovascular tissues, causing heart and lung disease as well as respiratory infections. Moreover, we are increasingly learning that by entering our bloodstream, these particles can interfere with processes throughout the body, including our immune systems.

Previous research from the University of Oxford has shown that, on average, diesel vehicles are responsible for at least five times more exhaust-associated health damage than petrol vehicles and 20 times more than electric cars.

The particulate matter in diesel exhaust has already been shown to exacerbate existing lung disease, such as chronic obstructive pulmonary disease and asthma, as well as heart conditions and certain types of cancer. But new research from the University of North Carolina at Chapel Hill has shown that it can affect our immune system too.

In a study published in the American Journal of Physiology: Lung Cellular and Molecular Physiology, the team collected blood samples from healthy volunteers and isolated a group of immature white blood cells—that is, white blood cells that haven't fully specialized for a specific role yet.

The cells were allowed to develop and mature before being exposed to diesel exhaust particles.

The exposed cells showed "dampened" phagocytotic function, meaning they were less effective at engulfing infected cells and bacteria. The exposed cells were also reprogrammed to produce high levels of inflammatory molecules, which can lead to tissue damage.

The researchers say these findings may be particularly concerning for those already suffering from a respiratory infection.

"These findings suggest that reprogrammed [white blood cells] may play an important role in the negative health outcomes following pulmonary infection and particulate matter exposure because of their highly inflammatory yet poorly antimicrobial nature," the authors write.

In a separate statement, lead author Ilona Jaspers, a professor at the University of North Carolina at Chapel Hill, said: "Exposure to air pollution has been routinely linked to worsening health outcomes. These findings may direct further research to this unique macrophage population, introducing new avenues of treatment to ensure proper macrophage function which in turn would improve immune responses and reduce disease severity."