Diffusion Tube Data Processing Tool

Overview

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 and a submission request for Northern Ireland.

A video is available on the AQ Hub which may be useful for authorities using the tool for the first time.

Current Version

Documents

Diffusion_Tube_Data_Processing_Tool_v5.3

Released: March 2025 (XLSB, 7.6 MB)
Latest Updates: Updated local bias adjustment summary table (continuous monitor data capture %).

Details

The tool includes steps to assist with:

1. Annualisation – the process of estimating annual mean NO₂ concentrations when data capture for the year is between 3 and 8 months (or between 25% and 75% if the Defra monitoring calendar has not been followed).
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).