Heathrow expansion: government is ignoring harms of 'ultrafine' air pollution

The London mayor Sadiq Khan and assembly members raised concerns last week about the increase in air pollution, greenhouse gas emissions and noise that will result from planned third runway at Heathrow airport.

They warned that this would reverse London's air quality gains from the Ultra Low Emissions Zone (ULEZ), and they asked for assurances that these impacts would be monitored.

Department of Transport has said it will use its "four tests on climate, air quality, noise and economic growth."

But what kind of air pollution comes from aviation, and is it being monitored?

Salamander asked air quality scientist Dr Pete Knapp, who was part of a team from Imperial College London who researched the impact of aviation on air pollution near Gatwick airport.

He explained that particles produced by combustion in jet engines are very small, around 5 - 15 nanometres in diameter and classed as "ultrafine particles."

If you can see the plane, pollution levels are high

High concentrations of ultrafine particles (UFPs) are produced by jet engines when taxiing, taking off and landing.

Knapp says that if you can see an aeroplane above you, then it is not yet cruising and the engines are emitting high amounts of UFP pollution.

It is likely that you are being exposed to UFP air pollution, on the ground.

Researchers have measured the impact of UFP pollution in communities over a kilometre away, downwind of airports. When the number of flights reduces overnight, the levels of ultrafine particles plummets.

UFPs can enter the brain through the nose

Due to their tiny size, around 25 times smaller than PM2.5, UFPs disperse around the body, lodge in the brain and other organs, and are highly harmful to health.

The can go into the eyes and directly into the brain, through the nose.

They increase the incidence of dementia, strokes, heart disease, asthma and diabetes and cancer, and lead to more premature deaths.

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UFP pollution is not being monitored

While air pollution from most urban sources, such as traffic and wood fired stoves, is now better understood and regulations are gradually improving, monitoring of ultrafine particles has lagged behind.

Department of the Environment, Food and Rural Affairs (DEFRA), local councils and across London, the Breathe London project, monitor the better known pollutants Nitrogen Dioxide, particulate matter 10 (PM10) and particulate matter 2.5 (PM2.5).

But these monitors cannot be used to measure levels of UFP pollution.

UFPs have such little mass that they do not show up in the cheaper, conventional monitoring of PM2.5. More expensive instruments that measure particle number, rather than mass, are needed to measure the concentration of UFP.

Expert committee advised more UFP monitoring

DEFRA's Air Quality expert committee advised the need for further monitoring of UFPs in 2018, pointing out that there were only three UK sites at the time which were performing continuous monitoring of UFP.

"The current measurement strategy is focused on the urban and traffic sources. It is insufficient to determine exposure from poorly understood UFP emission sources such as airports and shipping / ports, and also the way in which existing policies to reduce PM10 and PM2.5 are affecting UFP exposure.

"The group therefore recommends monitoring in other parts of the country, including the establishment of at least one permanent site monitoring in the vicinity of a major airport."

Seven years later, DEFRA has only four ultrafine particle monitoring sites across the UK, one at Horley near Gatwick. It does not show the live data.

Lack of research on impact of aircraft emissions on local community

A review by Dr Brian Stacey in 2019 confirmed that air quality research had focused on pollution from road traffic, power plants and incinerators, and these are the areas where regulation had emerged.

There had been less research targeted at measuring the direct emissions from aircraft of their impact on communities around airports, and there were gaps in our understanding of these emissions.

Aircraft engines emit large quantities of UFPs and these behave differently from the ultrafine particles found in typical urban locations.

The research team at Gatwick also found that 70-90% of the UFPs were 'volatile' (had reacted with gases after emission from the jet engines) and excluded from current International Civil Aviation Organisation (ICAO) legislation.

'Aviation industry is exploiting government's blindspot'

Both Heathrow and London City Airport have flight paths over densely populated and deprived areas, where communities are being exposed to this pollution.

Knapp says: "“Both the aviation and wood burning (Ecostove) industry are exploiting the government’s legislation blind spot on ultrafine particles.

"They know how damaging they are for public health, but profits are more important to them than the pollution our communities suffer.

"We need to use ultrafine particle pollution in our armoury against these industries; it strikes at their soft underbellies.”

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