This Network of particle counting, sizing and speciation equipment was established by Defra to research the nature of particulate matter in ambient air. Particulates are known to exacerbate symptoms of cardiovascular and respiratory diseases, and are also known to contribute to climate change, so the requirement for accurate measurement at UK sites is great.

The Network has two distinct aims:

• One aim is to provide information on the chemical composition of particulate matter, thereby providing information on sources and allowing the relevant chemical processes to be modelled more reliably. Ultimately, the network data contributes to achieving mass closure, accounting for the total mass of PM10 or PM2.5 in terms of the masses of its chemical components. However, the more immediate aim is to provide selected speciation of particulate matter at important sites.
  
  
• A second aim is to generate reliable datasets of airborne particle number concentration and size at selected sites. Long time series measurements of particle number are important for epidemiological studies, while size distributions provide important additional information on the processes involved in particle formation and evolution.

NPL took over the management of the Network in 2005, in collaboration with King's College London and the University of Birmingham. Improvements to the Network have been made, particularly in the areas of instrumentation, remote communications, data handling and quality assurance and control. Where possible, the equipment in use is automatic. This means that the particulate matter is constantly collected and analysed at each site, and the data are interrogated and collected remotely. The exceptions are the daily PM₁₀ and weekly PM_2.5 filter samples, which are analysed in the laboratory for elemental and organic carbon.

The monitoring programme comprises the following sites and measurements:

Reports on Network operation and data produced can be found on the UK-AIR: Air Information Resource page (on the Defra website).

Particles Network references 11/11

On the applicability of XPS for quantitative total organic and elemental carbon analysis of airborne particulate matter
Gilham R J J, Spencer S J, Butterfield D M, Seah M, Quincey P G
Atmospheric Environment 2008 42 (16) p3888-3891

Measurement and mitigation of response discontinuities of a widely used condensation particle counter
Gilham R J J, Quincey P G
Journal of Aerosol Science 2009 40 (7) p633-637

An evaluation of measurement methods for organic, elemental and black carbon in ambient air monitoring sites
Paul Quincey, David Butterfield, David Green, Mhairi Coyle, J Neil Cape
Atmospheric Environment 2009 43 (32) p5085-5091

Ambient air particulate matter PM10 and PM2.5: developments in European measurement methods and legislation
Paul Quincey and David Butterfield
Biomarkers 14 Issue S1 July 2009 p34-38