UK ambient air quality networks

Monitoring air quality to provide confidence in climate data  

Ambient air quality networks monitor compliance with air quality targets and generate valuable data to support policy setting and research activities.  NPL operates and manages three UK ambient air quality networks for the Environment Agency, which manages their delivery for Defra. 

1. The UK Heavy Metals Network measures the composition of 12 metals in PM₁₀ at 23 sites and assesses compliance with the European Air Quality Directive. We perform analysis at NPL using inductively coupled plasma mass spectrometry (ICP-MS). 

    

2. The UK Particle Numbers and Concentrations Network is a research network that performs measurements of particle number concentration (of particles > 7nm), particle size distribution, organic carbon or elemental carbon in PM_2.5, anions and cations, and chemical speciation.  

    

3. The UK Black Carbon Network is a research network which measures black carbon concentrations at 14 sites using aethalometers and is focussed on areas of high solid fuel burning. The UV channel of the aethalometers can be used indicates the presence of aromatic organic compounds.

NPL also contributes to the delivery of two other UK ambient air quality networks

1. The Automatic Urban and Rural Network (AURN) measures nitrogen oxides,  sulphur dioxide, ozone, carbon monoxide, PM_2.5 and PM₁₀ to assesses compliance against air quality targets and comprises a total of more than 170 sites. NPL performs the quality assurance and quality control activities for the London sites on the network.
2. The UK Urban NO₂ Network, where we deploy modified diffusion tubes in a collocation study and review key reports before they are submitted to Defra.
3. NPL also supports local air quality management (LAQM) through QA/QC of nitrogen dioxide diffusive sampler measurements. NPL carries out monthly field intercomparisons in central London with diffusion tubes and the reference method. This ensures that participating laboratories are maintaining the quality control of their sampler analysis for local authorities. NPL also employs local authority co-location study data to update the National Bias Adjustment Database, providing local authorities with bias factors to correct their NO₂ diffusion tube data.  

    

In addition to the routine operation of the networks, NPL also inputs into relevant CEN standardisation committees and delivers research to maximise the value of the data generated by the network. Examples of published research using network data includes:

• Policy implications of long-term changes in mass absorption cross-section derived from equivalent black carbon and elemental carbon measurements in London and south-east England
• Assessing trends in nickel concentrations in South Wales over the last five decades (subscription required - content behind paywall)
• Determination of antimony and barium in UK air quality samples as indicators of non-exhaust traffic emissions (subscription required- content behind paywall)

• Concentration trends of metals in ambient air in the UK: a review (subscription required - content behind paywall)

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