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<\/div>Jet engines produce large amounts of ultrafine particles<\/p>\n
Aerovista Luchtfotografie\/Shutters\u200btock<\/p>\n<\/div>\n<\/figcaption><\/figure>\n<\/p>\n
The health of more than 50 million people living within 20 kilometres of the busiest airports in Europe is being harmed by high levels of ultrafine air pollution emitted by jet engines, according to a study<\/a> commissioned by the campaign group Transport & Environment (T&E).<\/p>\n Some other studies suggest<\/a> that ultrafine particles can increase the risk of respiratory diseases, cardiovascular diseases, neurological conditions, diabetes and pregnancy issues, says Daan van Seters<\/a> at consultancy CE Delft in the Netherlands. Based on these studies, his team has now tried to estimate the Europe-wide impact.<\/p>\n However, ultrafine pollution is a little-studied aspect of air pollution and there are big uncertainties. \u201cThe research in this area is scarce and evidence is often not conclusive,\u201d says van Seters.<\/p>\n Much research on particulate air pollution has focused on particles smaller than 2.5 micrometres in diameter, known as PM2.5<\/a>. Ultrafine particles are a subset with a diameter of less than 0.1 micrometres<\/a>.<\/p>\n \u201cThat makes them very dangerous, because, being so small, they can get very, very deep into the human body,\u201d says Carlos L\u00f3pez de la Osa<\/a> at T&E.<\/p>\n Jet engines produce more ultrafine particles than other kinds of engines do, so people living or working near airports are most likely to be exposed to this form of air pollution. However, there are no effective limits on their levels.<\/p>\n <\/p>\n While ultrafine particles are a form of PM2.5, the limits for PM2.5 are for the total mass of particles per cubic metre<\/a> of air. Because ultrafine particles are so small, there can be huge numbers per cubic metre without exceeding PM2.5 limits.<\/p>\n In fact, there is very little monitoring of the levels of ultrafine particles at all, says L\u00f3pez de la Osa. \u201cWhat we have is mostly local studies around individual airports: Zurich, Amsterdam, Berlin, Los Angeles,\u201d he says. \u201cWe don\u2019t have a comprehensive view. That\u2019s one of the main reasons why we decided to launch this study.\u201d<\/p>\n To estimate the Europe-wide impact, van Seters and his colleagues first estimated the levels of ultrafine pollution around the continent\u2019s 32 busiest airports, based on numbers from the studies of individual airports. The team assumed that ultrafine pollution rises linearly with the number of flights and didn\u2019t consider wind patterns.<\/p>\n Next, based on studies looking at its health impacts, the researchers estimated that ultrafine pollution near the 32 airports has caused an extra 280,000 cases of high blood pressure, 330,000 cases of diabetes and 18,000 cases of dementia over the years.<\/p>\n \u201cThis is a first-order estimation based on extrapolation, and epidemiological research should be done to get more precise estimations,\u201d says van Seters.<\/p>\n But he thinks that, if anything, it is an underestimate. That is because the study looks only at 32 airports and only at people living within 20 kilometres, plus it excludes those working at airports.<\/p>\n In terms of exposed populations, Orly Airport near Paris tops the list, with more 6 million people living within 20 kilometres of it. London\u2019s Heathrow Airport is fourth, with more than 3 million people nearby.<\/p>\n The team\u2019s estimate of the health impacts relies heavily on a 2022 study of Schiphol airport near Amsterdam by Nicole Janssen<\/a> at the National Institute for Public Health and the Environment in the Netherlands and her colleagues. Janssen says her team was contacted by CE Delft, but advised the researchers against trying to quantify the impacts in this way given the large uncertainties.<\/p>\n However, she agrees that more research is needed. \u201cWe would like to stress our recommendation to further investigate the risk of ultrafine particles from aviation around other international airports,\u201d says Janssen.<\/p>\n There are several ways of reducing ultrafine pollution levels, says Krisztina Toth at T&E. It is possible to modify jet fuels \u2013 for instance, by reducing the sulphur content \u2013 to reduce ultrafine particle emissions. So-called \u201csustainable aviation fuels\u201d (SAF) also produce less ultrafine pollution.<\/p>\n \u201cBut we know unfortunately that it takes quite a while before the SAF production scales up enough so that it can have that impact,\u201d says Toth.<\/p>\n