UK Acid Gases and Aerosols Monitoring Network

The UK Acid Gases and Aerosols Monitoring Network has been in operation since September 1999, providing monthly measurement data of acid gases and aerosols as part of the UK Eutrophying and Acidifying Atmospheric Pollutants (UKEAP) project.

nitric acid network

In the first phase of the network, monitoring was implemented at 12 sites using the CEH DELTA (DEnuder for Long Term Atmospheric sampling) system, in an integrated fashion with the UK National Ammonia Monitoring Network (NAMN). An extension of the DELTA system at the NAMN sites is used to additionally sample gaseous HNO3, SO2, HCl and particulate NO3-, SO42-, Cl-, Na+, Ca2+, Mg2+, in parallel with monthly sampling of NH3 and NH4+ at the NAMN sites. To improve on the national spatial coverage, the network was increased from 12 to 30 sites in the second phase of the network, starting January 2006. The new expanded network also replaced measurements of gaseous SO2 and particulate SO42- previously made under the Rural Sulphur Dioxide Monitoring Programme, which terminated at the end of 2005.

The objectives of the network are to provide a long-term dataset of monthly speciated measurements of acid gases and aerosols that will be used:

  • to provide temporal and spatial patterns and trends, and compare results with dispersion models,
  • for Pollution Climate mapping and Acid Deposition Processes contract,
  • to contribute to mass closure from the measurements of several components of particulate matter (NO3-, SO42-, Cl-, Na+, Mg2+ and Ca2+) together with NH4+ from the closely integrated NAMN), which was one of the recommendations in the Department's Air Quality Expert Group's report on Particulate matter,
  • for calculation of national and regional deposition budgets, especially in upland areas which are sensitive to acid deposition.