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Guidance

Air pollution monitoring: Acid Gas and Aerosol Network (AGA Net)

How to get air pollution data from the AGA Net and the pollutants it measures.

The Acid Gas and Aerosol Network (AGA Net) monitors atmospheric pollutants at 28 stations across the UK.

The AGA Net provides information on the long-term rural trends of pollutants that:

  • make the environment more acidic (acidification)
  • cause excess nutrients in water (eutrophication)

The AGA Net provides monthly average air pollution data for:

  • concentrations of acid gases
  • compositions of inorganic aerosols

It is part of the UK Eutrophying and Acidifying Atmospheric Pollutants (UKEAP) Network that monitors long-term pollutant trends in rural and remote locations.

Get air pollution data

Get air pollution data from the AGA Net.

Pollutants the AGA Net measures

The AGA Net measures monthly concentrations of gaseous and aerosol pollutants.

Gaseous pollutants  

It measures the following gaseous pollutants:

  • ammonia (NH₃) 
  • nitric acid (HNO₃) 
  • sulphur dioxide (SO₂) 

Aerosol (airborne particle) pollutants 

It measures the following aerosol pollutants:

  • ammonium (NH₄⁺) 
  • nitrate (NO₃⁻) 
  • sulphate (SO₄²⁻) 
  • chloride (Cl⁻) 
  • sodium (Na⁺) 
  • calcium (Ca²⁺) 
  • magnesium (Mg²⁺)

Monitoring instruments

The AGA Net measures pollutants with CEH (UK Centre for Ecology and Hydrology) DELTA (DEnuder for Long-Term Atmospheric sampling) samplers.

AGA Net start date

The AGA Net started on 1 September 1999.

Latest  UKEAP  annual report 

The UKEAP annual report 2024 provides: 

  • network operation updates 
  • annual pollutant concentrations 
  • interpretation of data and trends 
  • a summary of scientific research, publications and other activities related to the network

Updates to this page

Published 25 June 2026
Last updated 21 August 2026 Show all updates
  1. Added to the list of pollutants the AGA Net measures: sulphur dioxide (SO2) and aerosols including chloride (Cl-), nitrate (NO3-), sulphate (SO42-), sodium (Na+), calcium (Ca2+) and magnesium (Mg2+).

  2. First published.

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