20 shocking facts about air pollution

You often can’t see it, or smell it, but air pollution kills. It contributes to up to 43,000 premature deaths a year in the UK - and that's just the first of 20 shocking facts about air pollution.

But don't despair. We're on a mission to clean up this hidden menace, and there are lots of things you can do to help.

1. Air pollution is a big killer – across the UK and the world

Every year outdoor or ambient air pollution contributes to around 4,000 premature deaths in London alone, up to 43,000 across the UK and worldwide the figure is 4.2 million according to estimates by the World Health Organization (WHO).

Indoor or household air pollution is also a problem from sources such as heating and cooking, particularly in the developing world.

2. It causes lung cancer, amongst other problems 

The WHO’s International Agency for Research on Cancer (IARC) has classified diesel engine exhaust, outdoor air pollution and separately its constituent Particulate Matter (PM pollution) as all carcinogenic to humans (Group 1), based on sufficient evidence that they cause lung cancer. This is the same category as smoking causing lung cancer.

Air pollution is linked to many diseases – short term exposure can trigger heart attacks and strokes. Longer term exposure is especially linked to respiratory and cardiovascular diseases, as well as many other health problems throughout life.

3. You can’t see air pollution

Particulate Matter (PM) air pollution is the most dangerous type and is more deadly when the particles are fine, smaller than the width of a human hair, and so are largely invisible. At this size they can penetrate deep into our lungs and from there can get into the bloodstream. Because of this it is thought they may affect every organ in the body, linking them to a host of diseases. They come from a range of sources including woodburning and road traffic.

Nitrogen dioxide – also known as NO2 – is a toxic gas that’s often colourless. This means you often won’t be able to see it, although sometimes an orange haze can be seen hanging over a city from a distance. NO2 inflames the lining of the lungs and reduces immunity to lung infections such as bronchitis. Road traffic is the biggest source. 

4. The most vulnerable are hit hardest

As well as older people who are more likely to suffer from existing health conditions, children are some of the hardest hit. Their lungs are still developing, they breath faster than adults and they're often closer to the ground and vehicle exhausts.

When growing up with bad air, childrens’ lungs can end up not developing properly, leaving them with 5% reduced capacity.

5. People of Colour and the most disadvantaged are worse affected 

Data from Friends of the Earth has found that People of Colour are 3 times more likely to live in neighbourhoods which have air pollution more than twice WHO guidelines for either or both of 2 key pollutants (PM2.5s and NO2).  

People living in these areas are also 3 times less likely to own a car than people living in other areas, meaning they are contributing the least to poor air quality.  

It's well accepted that more disadvantaged people tend to live near main roads where air pollution can be worse. But a recent study also found that “those in more deprived areas will likely have worse air quality regardless of whether they live in the city or more rural areas.”

6. UK targets are up to 4 times weaker than what the WHO recommend

The WHO revised their Air Quality Guidelines for air pollution in 2021 and the UK’s legal targets haven’t caught up. The current UK legal target for NO2 is now 4 times higher than WHO’s Guideline (40ug/m3 versus 10ug/m3). And the new legal target for PM2.5 in the UK’s Environment Act of 2021 is out of date and is 2 times the WHO Guideline (10ug/m3 versus 5ug/m3).  

The PM2.5 target is currently set to be met only by 2040. As it stands this means a child born in 2024 could still be breathing dangerously polluted air at 16.

New WHO aligned targets are urgently needed for the UK for at least these pollutants, with a new Clean Air Act to deliver this (there's an existing version of this proposed as Ella’s law). These should at least match what the EU plan, with the date to meet the current PM2.5 target of 10ug/m3 coming forward to 2030, and meeting an interim target for NO2 of 20ug/m3 by the same date, on the way to meeting the new WHO Guideline levels for both pollutants as soon as possible after that.

7. Much of England and Wales fails key WHO guidelines

Even on the weak current UK NO2 legal limits, the UK is still failing the 40ug/m3 target in places when these were originally due to be met by 2010.

For the new WHO guidelines, in England and Wales 50% of neighbourhoods were found to have levels exceeding the guideline for the toxic gas Nitrogen Dioxide (NO2), and 97% of neighbourhoods were found to have the most health damaging fine particles of air pollution (PM2.5s), according to data from Friends of the Earth.

8. Diesel cars are a particular problem

The number of new diesel car registrations has been falling since 2019. And that is just as well as the government is clear that diesel vehicles, and diesel cars in particular, are the largest source of NOx concentrations at the roadside. These are the areas of greatest concern and where road transport is overall responsible for 80% of the problem (see Figure 3).

Also, following the breaking of the "diesel gate" scandal in 2015, the concern over illegal devices designed to defeat official tests, leading to excessive pollution from diesel vehicles in real world driving, hasn’t gone away.

In Northern Ireland Friends of the Earth has been challenging the government there over where hundreds of thousands of diesel cars not to have received a legally required exhaust emissions test at MOT vehicle testing centres.

9. London’s ULEZ is working. As are Clean Air Zones elsewhere

Low or Ultra-Low Emission Zones (ULEZ) and Clean Air Zones keep the dirtiest vehicles from the most polluted areas and have been required in places as a result of the UK failing it’s NO2 legal limits. They work, but measures must be in place for people to be able to swap to cleaner vehicles or greener ways to get around.

London’s ULEZ covers the whole of London including Outer London as of 2023 and is working. The first 6-month report of the all-London zone shows that compared with what would've been the case had the ULEZ not been expanded to cover Outer London, NOx emissions from cars and vans in Outer London are estimated to be 13% and 7% lower, and PM2.5 exhaust emissions from cars and vans in Outer London are estimated to be 20% lower.

There are now Clean Air Zones in several other UK cities. In Birmingham and Bristol Clean Air Zones include cars which makes them much more effective. For instance Birmingham’s has also been shown to be working well and helping to protect people’s health.

10. Electric vehicles are only part of the solution

There were more than 1 million zero emission vehicles licensed to be on the road by the end of 2023, representing 2.5% of all vehicles. But much more needs to be done to help ensure vehicles that need to be on the road are clean vehicles. Key is the commitment to end the sale of new petrol and diesel cars by 2030 and the linked requirement on manufacturers (the ZEV Mandate), but also better charging infrastructure is needed.

But electric vehicles are only part of the solution. All vehicles, including supposedly clean electric vehicles, produce dangerous non-exhaust PM air pollution from brake, tyre and road wear. In fact, as exhaust emissions have decreased due to stricter emission standards, non-exhaust emissions are now the source of most road transport PM emissions. That is why we need massive investment in clean and affordable public transport and better integrated and safe cycling and walking routes to help people get out of their cars altogether.

11. New roads generate new traffic and aren't the solution to congestion

Road building isn’t in any way to help the economy. When looking at schemes after they’ve opened, 1 study showed “the majority had either no, weak, or anecdotal evidence of economic impact”, as pointed out by Transport for Quality of Life (TfQL).  

TfQL are also clear that “building roads does not solve congestion. Evidence for over 20 years shows that new roads encourage new journeys and open up land for car-dependent development which creates more traffic. This leads to a vicious circle of more congestion, more roads, more development, more traffic.”

12. Road miles driven need to be cut

Traffic levels have almost returned to pre-covid levels and haven’t been going down as needed, leaving domestic transport as the largest emitting sector for climate emissions in the UK in 2022, responsible for over a quarter of emissions. The RAC Foundation are adding their voice to say traffic needs to be cut to reach climate targets.

So for climate reasons, as well as air pollution, there's general consensus that a cut of at least 20% in car miles is needed by 2030. A national fair pay-per-mile scheme would really help (and has some strong support), together with redirecting funds from roadbuilding to giving people affordable and convenient green alternatives (while fixing potholes).

13. How, when and where you travel matters

Air pollution can be worse for those in cars, if travelling down a busy route, and at times when traffic is bad.

Being shut inside a car may not protect you from pollution. In fact, some studies show that walking or cycling can reduce the air pollution that we breathe, as can travelling by bus, in comparison to travel by car. For some pollutants car users can have up to 70% higher exposure levels than cyclists. Recirculating air in your vehicle is the best way to minimise exposure, whereas keeping windows open can worsen air quality inside your car.

The best time to run or jog is generally first thing in the morning, before the day’s traffic affects air quality. Choose your route. Research in London showed that children breathed 33% lower concentrations of traffic pollution when walking along back roads compared with busy main roads. If you can, try to exercise in green leafy spaces like parks, away from traffic. It can make a big difference – joggers inhale around 3 times more pollution than those walking the same distance. However on hot and sunny days the irritant gas Ozone can be worse away from main roads – see fact 19 below.

Whenever possible leave the car at home and help reduce pollution for everyone. More than half of car journeys in England are under 5 miles.

14. Aviation adds to bad air

Research shows that Heathrow Airport in London produces ultra fine particles (UFPs) which can be measured in central London nearly 20km away and all across the west of the city, as set out by Dr Gary Fuller of Imperial College London. He also sets out that research he led measured UFPs around Gatwick and found that UFPs 500 metres downwind of the airport was greater than that at the kerb of London’s busiest roads.  Aviation also adds to NO2 air pollution.

The government’s climate advisors, the Climate Change Committee (CCC) recommend stopping airport expansion until a UK-wide framework for managing aviation capacity is established.

15. Woodburning is a big problem

Domestic burning such as log burners and the dangerous particle air pollution they produce has been coming up the agenda as an issue.

In the UK, only 4% of homes that use solid fuel rely on it as their only heating source, yet wood and coal burning homes in the UK now produce more particle air pollution than the vehicles on our roads. Though research shows that when people are more aware of the issue they can moderate their behaviour.

The government has made some small moves on what fuel can be sold and standards on stoves. But campaign group Mums for Lungs are calling for the end of sales of new wood stoves by 2027.

16. Agricultural emissions harm people and nature

Agricultural sources, in particular livestock manure, urine and the spreading of inorganic fertilisers make up the vast majority of Ammonia gas emissions. These need to go down to meet 2030 targets.

Ammonia goes on to form the most health damaging particle air pollution – as so called secondary particulate matter. Particles are formed when ammonia combines with other pollutants such as Nitrogen Oxides, including from traffic.

Agricultural sources are a bigger problem for the appalling state of UK waters than sewage. And as a Nitrogen-containing compound (NH3), ammonia compounds cause significant long-term harm to sensitive habitats by increasing nitrogen concentrations in soil or water.

17. Air pollution threatens nature 

When soil nitrogen levels increase (such as from ammonia air pollution), common plant species that thrive in these conditions can dominate habitats at the expense of other rarer species.

As Plantlife point out over two thirds of our wild flowers require low or medium levels of nitrogen. Only robust species thrive in soils with high nitrogen levels. Species-rich grasslands, woodlands, heathlands and peat bogs are all under threat from air pollution. Plantlife further say that “over 90% of the UK’s landmass suffers from ammonia concentrations that are too high for sensitive lichens, mosses and liverworts to thrive.”  

Air pollutants such as ground-level ozone can interfere with chemicals producing an odour cue for pollinators. This can reduce honeybees’ ability to recognise scent by up to 90% from only a few metres away making it near-impossible to follow the trails of flowers.

18. Air pollution affects the climate, and the other way around

Many of the sources and solutions for air pollution and climate changing emissions are the same: combustion and burning of fossil fuels are key. There are strong benefits from tackling these issues together, using the win-win solutions to protect health and the planet.

Also air pollutants, such as black carbon and methane, are powerful short-lived climate pollutants (SLCPs) that contribute to climate change as well as ill health. "Black carbon, a component of [air pollutant] fine particulate matter, is one of the largest contributors to global warming after CO2. Black carbon warms the earth’s atmosphere by absorbing sunlight, thereby accelerating the melting of snow and ice. Methane, another SLCP [sources for which include agriculture] … is 84 times more powerful than CO2" (and methane is a precursor to the irritant gas ozone air pollution). Further, “ozone and black carbon affect weather processes and decrease agricultural yields, thus threatening food security.”

However “because SLCPs can be removed from the atmosphere in periods ranging from days to 15 years, reducing their emissions can make quick headway on slowing global warming.” Indeed “globally, comprehensive mitigation measures targeting SLCPs could cut the rate of global warming in half (a 0.6°C reduction) while helping to prevent 7 million premature deaths from outdoor and household air pollution annually, and preventing 52 million tonnes of crop losses annually by 2030.”

And more severe climate breakdown with hotter and sunnier weather can lead to increased air pollution in a number of ways. High pressure weather systems can mean stagnant air and a cocktail of pollutants getting physically stuck at ground level. Also there is increasing the risk of more harmful pollutants from wildfires and as more sunlight reacts with vehicle emissions ground-level ozone pollution is boosted which can irritate the lungs and eyes when levels are high.

19. Irritant ozone can lead to smog and is worse in rural areas

Separate to the natural ozone layer in the upper atmosphere (stratosphere), ground-level (tropospheric) ozone (O3) is formed when other pollutants, including NO2 such as from road traffic, react in sunlight and in severe cases summertime “smog”. 

However counter-intuitively ozone pollution can be worse outside cities eg. in the countryside and suburbs: “this is because certain pollutants that are more prevalent in urban areas are able to 'mop up' ground level ozone thus reducing its concentration.”

20. Air pollution costs the UK economy

Bad air costs us. As the Royal College of Physicians (RCP) and the Royal College of Paediatrics and Child Health (RCPCH) say: “the health problems resulting from exposure to air pollution have a high cost to people who suffer from illness, to our health services and to businesses. In the UK these costs add up to more than £20 billion every year.”

Not only does air pollution cost the NHS and result in worse productivity due to ill-health, but measures to cut air pollution can be beneficial to business. Strong action on air pollution can drive green innovation, and if the level of traffic is cut so should congestion. Less congestion and air pollution would make our cities and towns more attractive places to live, work, study and visit.

And globally “a World Bank report estimated that the cost of the health damage caused by air pollution amounts to $8.1 trillion a year, equivalent to 6.1% of global GDP.”