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Diffusion Tube Data Processing Tool


This diffusion tube data processing tool has been developed to assist local authorities in processing their NO2 diffusion tube monitoring data. It allows annual mean NO2 concentration results to be calculated from NO2 diffusion tube raw monthly data, by consolidating previous LAQM tools for processing diffusion tube monitoring data into a single tool. This serves to streamline the data processing requirements of NO2 diffusion tubes and improve the quality assurance associated with NO2 diffusion tube data processing. Through alignment of the output result tables with the annual reporting template requirements, the tool facilitates ease of population of the associated annual reporting data tables.

In addition, it provides an output table which can be directly uploaded into the LAQM Portal via the new Diffusion Tube Data Entry System (DTDES), which is part of the annual submission requirements for English local authorities (including London), Scotland and Wales.

video is available on the AQ Hub which may be useful for authorities using the tool for the first time. There is also an FAQ document on the hub to help with the tools. 

Current Version


Diffusion Tube Data Processing Tool v4.1

Released: May 2024 (XLSB, 7.2 MB)


The tool includes steps to assist with:

  1. Annualisation – the process of estimating annual mean NO2 concentrations when data capture for the year is below 75%.
  2. Bias Adjustment – the process of accounting for the variable accuracy of annual mean NO2 concentrations as measured by diffusion tubes relative to the chemiluminescent reference method.
  3. Fall off with Distance Adjustment – the process of estimating an annual mean NO2 concentration at a receptor location that is close to a monitoring site.
  4. Calculation of the Annual Mean Concentration.

Further information with regards to the use of the Diffusion Tube Data Processing Tool is provided within Technical Guidance LAQM.TG(22).

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