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Section 1: About air pollution

The pollutants and sources



Air pollution is an umbrella term for lots of different types of pollution in the air around us. All these pollutants can be inhaled and enter the body. Different types of pollution are caused by different sources and can affect the body in different ways. Air pollution is mostly invisible to the naked eye, but just because you can’t see it, it doesn’t mean it’s not there.


The Department for Environment, Food & Rural Affairs (Defra) lists the pollutants of concern as:

  • Sulphur dioxide (SO2)
  •  Nitrogen oxides (NOx)
  •  Particular matter (PM10, PM2.5 and PM1)
  •  Ozone and volatile organic compounds (VOCs)
  •  Toxic organic micro-pollutants (TOMPS)
  •  Benzene
  •  1,3-Butadiene
  •  Carbon monoxide
  •  Lead and heavy metals

Pollution is produced by sources inside and outside buildings, and significant concentrations of pollutants that arise from outside have been measured inside buildings. As most people spend most of their time indoors, the exposure to pollution inside buildings is an important consideration.


The location in which emissions are created also affects the impact on people’s health. For example, diesel emissions in cities tend to be more harmful to health than emissions from traffic on motorways because of the population density in cities. However, the World Health Organization and the Health Effects Institute are unequivocal in explaining there is no safe limit of particulate pollution; even at low concentrations, air pollution can damage your health.


Defra provides guidance on the activity that causes pollution in the UK:

It is clear that a few sectors have control over significant parts of the problem. Energy generation and transport is responsible for 56% of nitrogen oxides, which inflame airways and exacerbate symptoms in people with lung and heart conditions. Industry (particularly fast-moving consumer goods and agriculture) is responsible for over half of volatile organic compounds (VOCs) which can irritate people’s airways, create ozone and contribute to climate change. And agriculture alone is responsible for an estimated 88% of ammonia emissions, which react in the atmosphere to produce particulate matter (PM), contributing to cardiovascular and respiratory diseases.


Almost every business, regardless of sector, can make a meaningful contribution to improving air quality. Commuting and business travel are together responsible for almost half of all miles travelled per person in England (National Travel Survey, 2018). Almost 30% of particulate matter comes from industrial activity, with an additional 12% originating from road transport from both industry and for personal journeys. It is therefore vital that all UK businesses work to clean up their operations, supply chains and help employees drive cleaner and less frequently.

What can be done to reduce air pollution?


Outdoor pollution


The World Health Organisation recommends action on the following human activities that are major sources of outdoor air pollution, including:

Outdoor sources of air pollution: Fuel combustion from motor vehicles, Industrial facilities, Residential cooking, heating and lighting with polluting fuels, Heat and power generation, Municipal and agricultural waste sites and waste incineration/bur

Indoor pollution


The 2020 report “The Inside Story” by the Royal College of Paediatrics and Child Health and The Royal College of Physicians also provides guidance on combating the issue of indoor air pollution. It summarises that that approach to minimise the issue should include:


  • Avoid pollutants being generated or brought indoors, such as fires, candles, cooking or cleaning
  • Remove sources of pollution with known health effects, such as materials with VOCs formaldehyde and chemicals
  • Reduce exposure to pollutants with improved ventilation