Explainer

Air Quality: What causes air pollution?

We often think of traffic and transport as the biggest and most obvious causes of air pollution. In fact road pollution IS the biggest cause of nitrogen oxides in the UK but nitrogen oxides aren't the only type of pollution we have to deal with.

So what does create pollution? And where does it come from?

Some kinds of pollution are obvious such as particles from smoke and dust. 

Other kinds are invisible like gases and tiny particles and mean places that could be considered 'safe' can be a risk.

Causes of air pollution include:

  • Transport: Exhaust fumes - with diesel vehicles being the worst polluters. Brake and tyre dust are a large source of particle pollution in the air. The tiny particles can enter our lungs - and won’t be eliminated simply by changing to electric vehicles. Don’t forget major non-road pollution too: trains, shipping and aircraft.

  • Manufacturing/industry: The energy, processes, chemicals/products and transport involved.

  • Construction: Pollution is caused again by the processes, transport, dust and machinery.

  • Farming:  This another source largely through the use of pesticides and fertilisers - agriculture is the main source of ammonia pollution.

  • Heating: The method we use to heat our homes, such as gas and oil boilers and fires, can also create pollutants, as can methods of cooking.

All of these things and many more release particles and gases into the air which we breathe in and can affect our health. In fact air pollution is the biggest environmental risk to public health in the UK.

Other sources of pollution can be natural such as Saharan dust. 

The pollutants that come from the activities above that are most likely to damage our health are: 

  • Nitrogen dioxide

  • Ground level ozone

  • Particulate matter

  • Sulphur dioxide

You can find out more on these pollutants here

It’s worth knowing that air pollution isn’t just in towns and cities. It can travel long distances - just as Saharan dust does - with the weather and can affect areas far away from where it was produced - including the countryside and even different countries and continents.

Some of these causes of pollution can be easy to predict, others can vary greatly even within small areas.

Where air pollution can be predicted it is used to create the Daily Air Quality Index, and help forecast pollution levels

It is easy to stay up to date with the latest Daily Air Quality Index

Air Quality Index Example Credit: ITV Weather - with data from DEFRA and Met Office

 It uses a colour coded scale of 1 to 10.

Low air pollution is between 1 and 3, Moderate between 4 and 6, High is between 7 and 9, and Very High is 10 on the scale 

Air pollution levels Credit: ITV Weather, DEFRA and Met Office
  • 1-3: Enjoy your usual outdoor activities

  • 4-6: At risk individuals consider reducing physical activity outdoors

  • 7-9: Anyone experiencing discomfort should reduce physical activity

  • 10: Everyone should avoid or reduce physical activity

You can find more information on air quality on the CleanAirHub

For more information on air quality go to CleanAirHub.org.uk