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Black Carbon Network 

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 AE22. The Aethalometer measures the light absorption of carbon particles at two wavelengths: 880 nm (IR), to give the quantitative concentration of 'Black' or Elemental Carbon; and 370 nm (UV), to 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.

Monitoring method

Aethalometers quantify "black carbon" on filter samples based on the transmission of light through a sample. The sample is collected onto a quartz 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 absorption coefficient α [m-1] is calculated from the transmission, area and volume of the sample, and converted to a black carbon concentration, as a first approximation, using a mass extinction coefficient.

The aethalometers run on the Network operate at 2 wavelengths, 880nm and 370 nm. The 880nm wavelength is used to measure the Black Carbon (BC) concentration of the aerosol, while the 370nm 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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Page last modified: 23 March 2015