The UK PAH Monitoring and Analysis Network measures the concentrations of PAHs in ambient air at 31 monitoring sites across the UK (see map below). NPL took over the operation of the Network in September 2010.

The Network discharges the UK Government's obligation under the EC Air Quality Fourth Daughter Directive to monitor the mass concentration of benzo[a]pyrene (B[a]P) in the PM₁₀ fraction (particles with an equivalent aerodynamic diameter of 10 μm or less) of ambient air. The target value for B[a]P in the PM₁₀ fraction of ambient air, averaged over a calendar year, is 1.0 ng.m^-3.

Samples analysed and PAHs measured

The Network produces three types of samples:

• PM₁₀ particulate samples (31 sites) taken daily using a Digitel sampler fitted with a quartz filter.
  
  
• PM₁₀ particulate + vapour samples (2 sites) taken for 24 hours every three days with a Digitel sampler fitted with a quartz filter and polyurethane foam cartridge.
  
  
• Deposition samples (2 sites) collected fortnightly in deposition bottles.

All samples are chemically extracted and analysed for up to 39 PAHs using GC-MS. Further details of the analysis method are available.

Location of PAH Network sites

(Image courtesy of Defra
- click to enlarge)

Publications

• The Department of the Environment (DOE) in Northern Ireland, commissioned NPL to examine the levels of PAH monitored in Northern Ireland, and carry out modelling work so that levels of PAHs across Northern Ireland could be estimated. We also provided a cost benefit analysis to assess a range of abatement strategies. The full report can be downloaded here (PDF 4.7 MB).
• Annual Report for 2010 on the UK PAH Monitoring and Analysis Network