The UK Acid Gases and Aerosols Monitoring Network has been in operation since September 1999, providing monthly measurement data of acid gases and aerosols.

An extension of the DELTA system at the NAMN sites is used to additionally sample gaseous HNO₃, SO₂, HCl and particulate NO₃^-, SO₄^2-, Cl^-, Na⁺, Ca²⁺, Mg²⁺. The new expanded to include  measurements of gaseous SO² and particulate SO₄^2-

Established in 1996, the objectives of the network are to quantify temporal and spatial changes in air concentrations and deposition in NH3 and NH4+ (included since 1999) on a long term basis. The monitoring provides a baseline in the reduced nitrogen species (NH₃ + NH₄⁺), which is necessary for examining responses to changes in the agricultural sector and to verify compliance with targets set by international agreements.

There are 38 sites in PrecipNet at which the chemical composition of precipitation (i.e. rainwater) is measured. Six of the sites,
Lochnagar, Llyn Llagi, Scoat Tarn, Loch Chon/Tinker, River Etherow, Beaghs Burn and Crai Reservoir (Head of the Valleys) were specifically located within sensitive ecosystems. The network allows estimates of wet deposition of sulphur and nitrogen chemicals.

The nitrogen dioxide measurements are made at 24 of the 38 PrecipNet composition sites. Diffusion tubes are used to measure nitrogen dioxide. The tubes are mounted on the upright of the rain collector stand and exposed for four or five week periods throughout each year.

Triplicate nitrogen dioxide diffusion tube measurements are run at three AURN sites with co-located automatic instruments (Yarner Wood, Harwell and Eskdalemuir).