Types of Pollution - Air Quality Hub

Types of Pollution

What Counts as a Pollutant?

Anything that in sufficiently high airborn concentrations would have an adverse impact on health or the environment can be considered a type of air pollution, but in the UK a specific set of particle types are recognised from the perspective of local air quality management, and most of the focus is on a smaller set of three or four of the most common of those.

This focus is based in an understanding of what particles are emitted in highest volume and can be harmful with certain levels of ongoing exposure. Emissions of any less common (but still harmful) airborn substances are dealt with through strict regulation for sale and use.

CO2 is not considered a pollutant from an air quality perspective, since it does not directly harm health in emission concentrations that are observed. However, CO2 emissions are clearly of major concern from a climate change perspective and are considered a closely related area.

The Main Pollutants

As industrial emissions and the prevalence of domestic solid fuel burning reduced throughout the 20th century, the emissions of most concern became those relating to transport sources, as private vehicle ownership went up and congestion became an increasing problem. The emission type that most commonly causes exceedences of statutory levels is roadside nitrogen dioxide (NO2), and this remains a principle focus for emissions reductions.

There are also emissions reductions targets around the following pollutants which are considered a priority:

● Fine particulate matter (PM2.5)
● Ammonia (NH3)
● Nitrogen oxides (NOx)
● Sulphur dioxide (SO2)
● Non-methane volatile organic compounds (NMVOCs)

Other Pollutants

The full list of pollutants that have defined air quality standards in the UK is:

  • Nitrogen dioxide (NO2)
  • Nitrogen Oxides (NOx)
  • Particulate Matter (PM10)
  • Fine Particulate Matter (PM2.5)
  • Ozone (O3)
  • Sulphur dioxide (SO2)
  • Benzene
  • Lead (Pb)
  • Carbon monoxide (CO)
  • Benzo[a]pyrene (B[a]P)
  • Nickel (Ni)
  • Cadmium (Cd)
  • Arsenic (As)
  • 1,3-butadiene

Air quality professionals may also have involvement in the management of other potentially harmful or nuisance substances such as Radon gas, dust nuisance, smoke complaints etc. Some of these are very specific and definable, some are broad concepts that are nevertheless covered by legislative control or enforcement powers in some form.

While most of the UK does not experience acute exceedences of these pollutants, some locations with particular industries or other features may require special focus.