You often can’t see it, or smell it, but air pollution kills. It is linked to 40,000 early 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.
And when you've mugged up on the air pollution facts, why not take a deep breath - and test your knowledge with our Clean Air Quiz.
1. Air pollution is one of the UK’s (and the world’s) biggest killers
Breathing in air pollution can increase the risk of heart disease and stroke. It worsens asthma symptoms and can even cause lung cancer.
To address this, as a first step we are calling on the government to phase-out of diesel vehicles by 2025.
Worldwide, the human costs of indoor and outdoor air pollution are terrible - millions of premature deaths each year are linked to air pollution.
2. Children are most vulnerable to air pollution – but we are all affected
The impacts of toxic air are worse for the most vulnerable people. Air pollution damages children’s lung development. It also makes existing respiratory and cardiovascular conditions worse, particularly in older people. The poorest people in our society tend to suffer more as they tend to live near main roads where air pollution is worst.
All road users are affected by air pollution. However, pedestrians and cyclists are often exposed to less air pollution than people in vehicles, especially if using backstreets.
3. A child born today might not breathe clean air until they are 8
Long-term childhood exposure to air pollution can lead to permanently reduced lung function. Dirty air has been shown to affect the development of foetuses as well.
Most areas of the UK are breaking EU limits on air pollution. Yet the government's current plans won't reduce pollution to legal levels until at least 2020 – and in London, 2025.
Think you know enough? Take the Clean Air Quiz
Or read more shocking facts about air pollution ...
4. Air pollution causes around 40,000 early deaths a year in the UK
Outdoor air pollution is responsible for the equivalent of 40,000 premature deaths a year in the UK, says the Royal College of Physicians and Royal College of Paediatrics and Child Health.
Fine particle air pollution is responsible for 29,000 early deaths a year. The effect of the toxic gas nitrogen dioxide (NO2) brings the figure up to 40,000 a year.
5. Air pollution was bad then…
In the 1970s the UK was known as the Dirty Man of Europe.
Pollution from the UK’s coal-fired power stations caused acid rain. Forests across Europe withered. EU action thankfully put an end to this.
As a result, sulphur dioxide emissions dropped by 94% by 2011. This prevented an estimated 46,000 premature deaths between 1990 and 2001.
6. And air quality is still bad now
Invisible pollution claims more than 9,000 early deaths each year in London.
London’s air is some of the dirtiest in Europe. In 2016 the government was ordered by the High Court to come up with a plan to clean up air across the UK in the shortest possible time.
7. Five days into 2017 annual air pollution limits in London were breached
Just 5 days into the new year Brixton Road in London breached air pollution limits for the whole of 2017.
EU air pollution rules say monitoring stations must not record particularly high levels of nitrogen dioxide more than 18 times a year at any given location. But Brixton Road, in London, exceeded this limit for the 19th time on 5 January 2017.
A number of other London locations, including Putney High Street and Brompton Road in Knightsbridge, followed shortly.
8. Sitting inside a car can be more dangerous for your health
Being shut inside a car may not protect you from pollution. In fact, you can be exposed to almost 8 times as much as a cyclist.
When driving in heavy traffic, use the recycled-air setting on your fan so your car doesn’t suck in harmful fumes.
9. Two thirds of all UK car journeys are under 5 miles
By leaving your car at home, you are helping reduce air pollution for everyone. You can make it safer for yourself by avoiding busy main roads when walking.
But if you can’t avoid a main road, walk as far away from the kerb as you can – even a few metres can make a difference to your level of pollution exposure.
10. About 11 million cars were designed to cheat air pollution tests
It has long been known that diesel cars pollute far more in the real world than in laboratory tests. A 2016 study by the Department for Transport confirmed this, finding that all diesel cars tested produced more pollution on the road than in the laboratory - some emitted up to 12 times the EU maximum.
Worse still, in 2015 car manufacturer Volkswagen was caught using software programmes to cheat emissions tests.
Volkswagen eventually admitted to fitting this software to millions of its diesel vehicles. Basically they were programmed to spew out less filth in the lab than on the road.
The ramifications of this shocking deception continue to rumble on, with record fines imposed on Volkswagen in the US and legal action mooted in Europe.
11. There’s been a 26-fold increase in electric cars in the UK in the past 4 years
Tax incentives for low- and zero-emission cars are an essential part of the solution to air pollution. But so is massive investment in clean public transport and better integrated walking and cycling routes, to help people get out of their cars altogether.
Fact: In the past 4 years, the number of registered electric cars in the UK has increased by around 2,600%.
New registrations of electric cars rose from 3,500 in 2013 to almost 95,000 by the end of March 2017. Data from the Society of Motor Manufacturers and Traders show that around 500 electric cars were registered per month during the first half of 2014. By the end of 2016, more than 35,000 plug-in cars had been registered over the course of the year – the highest number ever – and an average of over 3,000 per month.
There are plans in the Netherlands and Norway to halt the sale of diesel and petrol cars entirely from 2025. Friends of the Earth is calling for similarly radical action in the UK.
12. There are around 12 million diesel cars on UK roads
Diesel vehicles now represent more than 40% of new car sales in the UK, up from around 13% little more than a decade ago. There are approximately 12 million diesel cars on the road in the UK at the moment.
This is largely the result of government incentives based on the carbon savings and greater fuel efficiency of diesel compared to petrol. Diesel cars produce high levels of deadly NOx, more than their petrol equivalents.
13. Air pollution costs the UK £20 billion a year
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 our health service and result in worse productivity due to ill-health, but measures to cut air pollution are beneficial to business. Strong action on air pollution can drive green innovation, and if traffic levels are cut so should congestion. Less congestion and air pollution would make our cities and towns more attractive places to live and work and visit.
14. The global cost of air pollution is staggering
The global cost of air pollution is US$225 billion annually, according to the World Bank.
A study by the World Bank and the Institute for Health Metrics and Evaluation (IHME) highlights the eye-watering economic and social impacts of dirty air. It makes clear what's fairly obvious: polluted places are less productive, see fewer tourists, and put off potential workers.
In a survey of the world’s liveable cities – London came 38th due to traffic and air pollution.
15. Air pollution makes climate change worse
As well as fine particle air pollution directly affecting the climate, many of the causes of air pollution – such as traffic emissions – are also contributors to climate change.
There are strong benefits from tackling these issues together.
16. The smallest particles are the most dangerous
The most dangerous tiny particles of air pollution are smaller than the width of a human hair. This means they are largely invisible. And they can penetrate deep into our lungs.
Particle air pollution worsens heart and lung disease.
17. That orange haze is nitrogen dioxide… and it’s toxic
Nitrogen dioxide – also known as NO2 – gets worse the closer you go to road traffic.
It is a toxic gas which is 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 lung and reduces immunity to lung infections such as bronchitis.
18. Diesel exhaust causes cancer
The World Health Organisation (WHO) has declared outdoor air pollution, including particulate matter (PM) and also diesel exhaust, carcinogenic to humans, in the strongest class (Group 1). That's the same class as tobacco.
19. Time of day matters
The best time to run or jog is generally first thing in the morning, before the day’s traffic affects air quality.
If you can, try to exercise in green leafy spaces like parks. It will make a big difference – joggers inhale more pollution than those walking the same distance.
20. Plants can filter pollution
Our homes are vulnerable to noxious gases which can build up over time.
Readily-available houseplants can help filter some harmful compounds out. Helpful plants include: peace lilies, English ivy, cornstalk dracaena and broadleaf lady palm.