Researchers from King’s College London have, for the first time, measured ultra-fine particles across four major European cities.
They found airports were a significant source of ultra-fine air pollution particles.
While traffic pollution remains the most dominant source of pollution, the study, published in Environment International, found London had the highest concentration of ultra-fine particles compared to other cities with the greatest concentration coming when wind was blowing from the airport towards the city centre.
London is surrounded by airports, the busiest being Heathrow with 480,000 plane journeys in 2018. The airport is just over 11 miles from the air monitoring station in North Kensington used by researchers for the study. A second station was based on Marylebone Road.
Dr Ioar Rivas, research fellow and author of the study, said: “We expected traffic emissions to be an important source of ultra-fine particles in cities but we now know that airport emissions, even if located at the outskirts of the city, can travel far enough and reach populations in urban areas away from the airport.”
Most air pollution studies have looked at the levels of larger particles, smaller than 2.5 micrometres, but this latest study looked at smaller ultra-fine particles less than 0.1 micrometres in size.
The smaller the particle, the deeper it can penetrate into the lungs, and ultra-fine particles have been linked to brain cancer.
Cars contributed the most air pollution across all four cities, ranging between 71 per cent and 94 per cent.
Dr Gary Fuller, senior lecturer in air pollution measurement, added: “Cities around Europe have polices to reduce airborne particles from traffic that should also reduce people’s exposure to ultra-fine particles, but aircraft emissions are not being addressed in the same way.”
The research team now plans to study the effects of the different sources of ultra-fine particles on mortality and hospital admissions.
Meanwhile, researchers from the Barcelona Institute for Global Health have also linked exposure to ambient air pollution with lower bone-mass levels in humans.
The research, published in JAMA Network Open, looked at the bone health of more than 3,700 people from 28 villages outside the city of Hyderabad, in southern India.
Each participant was assessed using a type of radiography that measures bone density as well as having the bone mass calculated. The results of the study showed that exposure to ambient air pollution, particularly to fine particles, was associated with lower levels of bone mass.
Lead researcher Otavio Ranzani said: “This study contributes to the limited and inconclusive literature on air pollution and bone health. Inhalation of polluting particles could lead to bone-mass loss through the oxidative stress and inflammation caused by air pollution.”
Cathryn Tonne, coordinator of the study, added: “Our findings add to a growing body of evidence that indicates that particulate air pollution is relevant for bone health across a wide range of air pollution levels, including levels found in high-income and low-and-medium income countries.”