Please note that the UK Black Carbon Network data are now obtained with the new AE33 Aethalometer model. This model was installed at all sites in November 2019.

UK-Air ratified Black Carbon Network results collected since November 2019 should be treated with caution when comparing AE33 data with previous years measurements, when the AE22 model was used. Although methodology, in principle, is the same, both models use different algorithms and factors to calculate the final black carbon mass concentration. A comparison campaign at a London urban background site suggested two parameters affecting the data continuity from the equipment change. These are the multiple scattering factor, C, and ”Mean Ratio” factor. More information on what these parameters mean can be found in Drinovec et al. (2015) and Ciupek et al. (2021) or at www.aerosol.si. Further information can be also obtained by contacting NPL at pcnbctechnical@npl.co.uk

Data from the AE33 and AE22 comparison campaign are under review and will be published later in 2022. This statement will be updated in due course.

References
Drinovec, L., Mocnik, G., Zotter, P., Prévôt, A. S. H., Ruckstuhl, C., Coz, E., Rupakheti, M., Sciare, J., Müller, T., Wiedensohler, A., and Hansen, A. D. A.: The "dual-spot" Aethalometer: an improved measurement of aerosol black carbon with real-time loading compensation, Atmos. Meas. Tech., 8, 1965–1979, https://doi.org/10.5194/amt-8-1965-2015, 2015.

Ciupek, K., Quincey, P., Green, D.C., Butterfield, D.,  and  Fuller, G.W.: Challenges and 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 in 2014–2019, Environ. Sci.: Processes Impacts, 2021,23, 1949-1960, https://doi.org/10.1039/D1EM00200G

Introduction

The UK Black Carbon network is managed and operated for Defra and the Devolved Administrations by the National Physical Laboratory (NPL).

What is measured?

Black carbon concentrations are measured using the Magee Aethalometer, model AE33. The Aethalometer measures the light absorption of carbon particles at seven wavelengths from the near-infrared (950 nm) to the near-ultraviolet (370 nm). Results from channel 880 nm (IR), give the quantitative concentration of 'black' carbon and 370 nm (UV) indicate the presence of aromatic organic compounds such as are found in wood smoke, biomass-burning smoke, and tobacco smoke.

What is the purpose of the network?

The UK Black Carbon research monitoring programme began operation on 1st September 2006. The purpose of the network is to continue a historical data set of black smoke which dates back to the 1920s and monitor black carbon concentrations.

The Black Carbon Network was reviewed and streamlined in 2012 and the report summarising the objectives and new structure is available for download (PDF 931 KB)

How is the network run?

The Aethalometer is a stand alone instrument that will run unattended for months at a time, with data being collected remotely via a modem on a daily basis.

The Black Carbon Network is currently made up of the following sites.

• Auchencorth Moss
• Ballymena Ballykeel
• Belfast Centre
• Birmingham A4540 Roadside
• Birmingham Ladywood
• Cardiff Centre
• Chilbolton Observatory
• Detling
• Glasgow High Street
• Glasgow Townhead
• Kilmakee Leisure Centre
• London Marylebone Road
• London N. Kensington
• Strabane 2

Monitoring method

Aethalometers quantify "black carbon" on filter samples based on the transmission of light through a sample. The sample is collected onto a teflon tape, and the absorption coefficient of the sample is measured by a single pass transmission of light through the sample, measured relative to a clean piece of filter. The rate of change of the attenuation of light, together with flow, area and volume of the sample are mathematically converted to the compensated particle light absoption and a black carbon mass concentration.

The aethalometers run on the Network operate at 7 wavelengths, 950 nm, 880 nm, 660 nm, 590 nm, 520 nm 470 nm and 370 nm. The 880 nm wavelength is used to measure the Black Carbon (BC) concentration of the aerosol, while the 370 nm wavelength gives a measure of the "UV component" of the aerosol. At wavelengths shorter than about 400 nm, certain classes of organic compounds (such as polycyclic aromatic hydrocarbons, and also certain compounds present in tobacco smoke and fresh diesel exhaust) start to show strong UV absorbance. The UV component can be used as a tracer for oil and solid fuel emissions.

Further information and data regarding the Black Carbon Network's operation are available in the PDF Annual Report - Download 2013 Annual Report for the UK Black Carbon Network (PDF 4.23 MB).

View data for sites in this network

Data can be downloaded from the Data Selector section of this website.

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