Millions at risk from ultrafine air pollution caused by airplanes

The health of more than 50 million people living within 20 kilometres of Europe's busiest airport is being harmed by high levels of ultrafine particle pollution from jet engines, according to a report. the study It was commissioned by campaign group Transport & Environment (T&E).

Several Other studies It says ultrafine particles can increase the risk of respiratory diseases, cardiovascular diseases, neurological diseases, diabetes and pregnancy problems. Darn Fun Setters His team, working at the Dutch consultancy CE Delft, are using these studies to try to estimate the impact for Europe as a whole.

But ultrafine particle pollution is a less-studied aspect of air pollution and there is a lot of uncertainty: “There is little research in this area and the evidence is often inconclusive,” Van Seters said.

Most research on particulate air pollution has focused on particles smaller than 2.5 micrometers in diameter, so-called PM2.5. Ultrafine particles are particles smaller than 0.1 micrometers in diameter.

“They are very dangerous because they are so small and can get very deep into the human body.” Carlos Lopez de la Osa At T&E.

Jet engines emit more ultrafine particles than other types of engines, so people who live or work near airports are most likely to be exposed to this form of air pollution, but there are no effective limits on its levels.

Ultrafine particles are a type of PM2.5, but PM2.5 limits are set for the total mass of particles per cubic metre of air. Ultrafine particles are so small that even a huge number of particles per cubic metre would not exceed the PM2.5 limit.

In fact, there's very little monitoring of ultrafine particle levels, says Lopez de la Osa. “What we have are mostly regional studies around individual airports like Zurich, Amsterdam, Berlin, Los Angeles,” he says. “We don't have a comprehensive view, and that's one of the main reasons we decided to launch this study.”

To estimate the impact across Europe, van Seters and his colleagues first estimated ultrafine particle pollution levels around the continent's 32 busiest airports, based on figures from surveys of individual airports. The team assumed that ultrafine particle pollution increases linearly with the number of flights and did not take wind patterns into account.

Next, based on studies looking at health effects, the researchers estimated that ultrafine particle pollution near 32 airports was responsible for an additional 280,000 cases of hypertension, 330,000 cases of diabetes, and 18,000 cases of dementia over the years.

“This is a first-order estimate based on extrapolation, and we need to do epidemiological studies to get more precise estimates,” Van Seters said.

But he thinks that, if anything, is an underestimate because the study only looked at 32 airports and people living within 20 kilometres, and excluded people who work at the airports.

In terms of population at risk, Orly Airport near Paris tops the list, with more than six million people living within 20 kilometers of the airport, while London's Heathrow Airport comes in fourth, with more than three million people living within the airport's vicinity.

The research team's estimates of health effects rely heavily on a study carried out in 2022 at Schiphol Airport near Amsterdam. Nicole Jansen Contacted by CE Delft, Janssen and her colleagues at the National Institute for Public Health and the Environment in the Netherlands said they advised researchers not to try to quantify the impact in this way because of large uncertainties.

But they agree that more research is needed: “We would underscore our recommendation to further investigate the risk of ultrafine particles from aircraft around other international airports,” Janssen said.

There are ways to reduce ultrafine particle pollution levels, says Christina Toth of T&E. Jet fuel can be improved to reduce ultrafine particle emissions, for example by reducing its sulfur content. So-called “sustainable aviation fuels” (SAF) also reduce ultrafine particle pollution.

“Unfortunately, we know it will be a long time before SAF can be produced at scale and be effective,” Toth says.

Limiting airport expansion and flight frequencies and encouraging alternative modes of transport would help, and would also limit flying's impact on the climate.