25th June, 2024
What are ultrafine particles? Ultrafine particles (UFPs) are a type of particulate matter (PM) emissions with a diameter less than or equal to 0.1 micrometres. Exposure to UFP can increase the likelihood of pulmonary, cardiovascular and ischemic heart diseases. It also has an association with increased rates of dementia and diabetes. There is some evidence that indicates that the relatively small size of UFPs results in a deeper penetration into the body and the ability to carry relatively more toxicants due to surface-area to mass ratio.
A new report published by a leading European transport campaign group, T&E, finds that ultra-fine particles (UFPs) from aircraft could pose serious health risks to the populations around airports. Using extrapolated data, the report suggests that at the four UK airports studied – London Gatwick, Stansted, Heathrow and Manchester – UFP from aircraft could be associated with, in total, an additional 41,000 cases of high blood pressure, 44,000 cases of diabetes and 2,200 cases of dementia.
The study provides an estimate of the scale of health effects caused by aviation in Europe, by extrapolating data from Schiphol Airport in Amsterdam. It takes into account population exposure at major airports, and adjusts for the health impact of other factors such as noise and other air pollutants in order to identify the harm caused specifically by UFPs. Actual risk for any individual will vary depending on their personal circumstances, the report notes, as well as their ‘exposure history’ (how long they have lived near the airport, for example).
Work published in 2022 by UK academic Gary Fuller, who studied pollution levels near Gatwick airport, found that mean particle number concentrations at the measurement locations “were similar to concentrations measured just two metres from the highly trafficked road in central London”.
This is one of a small number of studies on UFP concentrations in the UK – there are only three long-term UFP monitoring sites in the UK. A review published in 2021 reported that there were 30 studies that investigated air quality including UFPs near airports, with the majority of these in the US and Europe. Studies on aviation-related air pollution and health are even more limited and have considerable variance in methodology. A few studies have measured the effects of short-term exposure to aviation-related air pollution in small groups of volunteers and found reductions in lung function. Long-term exposure studies use population data and hospital admissions or disease rates to try and estimate the impact of air pollution on causing specific diseases. Lastly, there have been four toxicological studies that have shown inflammation and cellular damage resulting from aviation exhaust toxicity.
There is a significantly wider evidence base covering the health impacts of UFPs in general (not specific to aviation), which suggests that while the precise role of UFPs in causing diseases is often unclear, they pose a potentially major health risk.
In the UK, air pollution laws provide some protection from dangerous levels of pollutants such as nitrogen oxides and particulate matter generally (including UFPs), but there are no legal limits focused specifically on levels of UFPs. A growing body of evidence links UFP exposure with various forms of cancer, heart disease, COPD and respiratory diseases. Data also indicates a connection between air pollution and dementia.
Several of the airports covered by the new study are planning to grow their operations. Stansted Airport secured permission to expand in 2021, Gatwick Airport has applied for permission to expand its operations such as to permit a 70% increase in passenger numbers, and Heathrow has indicated that it could come forward with an application for a third runway in the near future.
Pollution from aircraft is generally only modelled when planes are landing and taking off, up to 3,000 feet. Pollutants released in the upper atmosphere are not counted on the basis that it is difficult to attribute them to any particular source. Decisions on the health impacts of airport expansion do not therefore take into account the impact of UFPs.
Aircraft fuel is over 99% fossil kerosene. There are no hydrogen or electric passenger planes on the market and for the short to medium term these kinds of planes are likely to be small and to cover only fairly short routes. It is possible, the report says, to ‘hydrotreat’ jet fuel such as to reduce the amount of particulate matter it contains. So-called ‘sustainable aviation fuels’ (SAFs) may also generate fewer particulates than fossil kerosene. There would be no reduction in the CO2 released by hydrotreated or ‘sustainable’ fuels, however, so they would still cause climate warming.
Tim Johnson, the Director of the AEF, said in the UK press release for the report that:
Communities living around airports have been raising the alarm around air pollution for years and this report vindicates their position that more should be done. With public health already impacted by exposure to aircraft noise, UFPs from aircraft create yet another environmental health concern. A UK-wide review of air pollution at airports is long overdue, with the last evaluation taking place over 20 years ago. There is an immediate opportunity for intervention, with options such as hydrotreating fuels or reducing air traffic providing dual climate and health benefits. Ultimately, this is another reason why airport expansion is irresponsible at this time. Any expansion will only lead to greater air pollution and therefore a greater number of people negatively affected.”
The campagne groups and AEF members CAGNE, GACC, HACAN, TAG, and SAW each issued their own statement on the new report from T&E: