LONDON – A BBC journalist has become one of the first people in the world to directly observe the effects of air pollution within his own body, revealing microscopic traces of carbon and chemical compounds embedded in his red blood cells after just ten minutes of exposure to traffic fumes in central London.
James Gallagher, presenter of BBC Radio 4’s Inside Health, participated in an experiment led by Professor Jonathan Grigg at Queen Mary University of London to understand how air pollution impacts human health. The experiment involved standing alongside a busy four-lane road, breathing in the exhaust and particulate matter emitted by vehicles.
Under a microscope, Gallagher’s blood samples revealed compact black spots clinging to his red blood cells – fragments of carbon and other chemicals resulting from the incomplete combustion of fuel, known as PM 2.5 particles. These particles, less than 2.5 micrometers in diameter, are small enough to enter the bloodstream.
“It’s a little perturbing to observe that, isn’t it?” said researcher Norrice Liu, who analyzed the blood samples. “On average, one in two or three thousand red blood cells contained a fragment of pollution that had been transported. That may not seem like much, but if you compare it to the five liters of blood in an adult, researchers estimate there could be 80 million red blood cells carrying pollution throughout the body.”
The findings underscore the pervasive nature of air pollution and its ability to bypass the body’s natural defenses. Professor Grigg explained that the initial assumption that pollutants are filtered by the nose or mouth and expelled by the lungs is inaccurate. His team is investigating whether these smaller particles not only remain in the lungs but also enter the bloodstream and circulate throughout the body.
The research indicates that the pollution doesn’t simply disappear. While some may be filtered by the kidneys and excreted through urine, Professor Grigg believes the most likely scenario is that the particles “move along the lining of blood vessels and lodge in various organs.” This could explain the link between air pollution and a range of health problems extending far beyond the respiratory system, including cardiovascular disease, neurological disorders, and even impacts on fetal development.
Studies have found deposits of black carbon from air pollution within the human body, including in placentas analyzed after birth, suggesting that pollutants can reach developing fetuses. Other pollutants, such as nitrogen oxides, while invisible under a microscope, are also known to cause damage.
The World Health Organization (WHO) estimates that 99% of the global population breathes polluted air, contributing to seven million deaths annually. In the United Kingdom, a report by the Royal College of Physicians estimates 30,000 deaths per year are linked to air pollution.
Stephen Holgate, who led the Royal College of Physicians report, stated that the harmful effects of air pollution on health are “clear, cut and dried,” and are most evident in areas where pollution levels are being reduced. However, he noted that because air pollution is now largely invisible, many people are unaware of its presence and underestimate its daily harm.
Inflammation is believed to be a key mechanism by which air pollution damages organs. This inflammatory response can increase the risk of heart attacks and strokes, and has been linked to the activation of latent cancer cells in the lungs, contributing to approximately one in ten lung cancer cases in the UK. Air pollution is also thought to disrupt DNA function during critical stages of fetal development, potentially leading to smaller lungs and hearts, and impacting brain development.
Experts recommend minimizing exposure to air pollution by walking along quieter side streets or staying further away from traffic. FFP2 masks have been shown to reduce the amount of pollution entering the bloodstream, though Professor Grigg cautions against recommending widespread mask use. However, he suggests that clinically vulnerable individuals may benefit from wearing masks in highly polluted areas.
Professor Grigg emphasized that addressing air pollution requires systemic changes, including transitioning to electric vehicles and implementing stricter emission standards for gasoline and diesel engines. “The more we understand the mechanisms that cause these effects, the more People can pressure policymakers to reduce exposure, because ultimately that is the solution,” he said.
