Breathing polluted air harms our health, even though we might not feel the effects day-to-day.  

7.9 million Londoners – nearly 95% of the capital’s population – live in areas that exceed the
World Health Organisation’s pollution guidelines by 50% or more. 



What is air pollution? 

Air pollution is anything in the air that causes harm, but the pollutants of biggest current concern in the UK are particulate matter (PM) and the gas nitrogen dioxide (No2).  
Particulate matter is all solid and liquid particles suspended in the air. These are both man-made  (such as diesel, soot) and natural  (such as sea spray, dust and pollen).  
The size of particles in the air varies. PM 10 has a diameter of 10 micrometers or less, whereas PM 2.5 has a diameter of 2.5 micrometers or less – and is often described as ‘fine particles’. These finer particles are the biggest concern, because they’re small enough to be breathed deep into our lungs.  
By way of comparison, a human hair is about 100 micrometres, so roughly 40 fine particles make up the width of one strand of hair! 
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PM 2.5

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Where does it come from?

The majority of fine particles we breathe in cities are man-made; natural sources only make a small contribution. In London 50% of pollution comes from traffic. Pollution also comes from burning fuels in homes or businesses, and soot and dust from industry and construction.  
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Website illustrations

PM 2.5


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What’s the impact on our health?  

Air pollution is linked to respiratory and cardiovascular issues, though research is increasingly showing how it impacts almost all organs in our body, including the brain. 
Health research is mostly carried out using data from large groups of the population. For example
studies look at the numbers of people that end up in hospital on high pollution days compared low pollution days; average life expectancies for people living in areas with high levels of air pollution compared to lower levels; or by comparing how different levels of pollution impact the development
and size of children's lungs. 
Scientists tend to study the health impacts of one pollutant at a time. But in reality we inhale a mixture with each breath. That mixture is different in our home and office, in the tube or on your bike. We don’t
yet know which pollutant is most harmful but we do know that breathing less air pollution reduces the health risk.  
Read the World Health Organisation’s summary of health impacts or check out this Interactive Guide


How much pollution do I breathe? 

Large monitoring stations tell us how much pollution is in the air. The ‘London Air Quality Network’ looks after the London air quality monitors. You can find out levels of pollution near you here.
What we know less about is how much individuals are exposed to pollution as they move  around  cities. How much bad air you breathe in will depend on how you travel, what routes you take, the spaces you’re in and what the weather’s like. Generally the closer you are to busy roads the more pollution  you’ll breathe in
To find out how much we’re actually breathing in, 10 Londoners carried air quality monitors for one week. Read their stories and see how your daily routine compares. 


Feeling exhaust-ed?

There’s lots we can all do to improve the air we share