Created 7 months ago, updated 7 months ago

Air pollution is monitored by the London boroughs within their own area. There are a number of different monitoring methods available, including diffusion tubes. Nitrogen dioxide diffusion tubes are small, passive samplers which measure the concentration of nitrogen dioxide in the air at a certain location, providing a monthly average measurement. The diffusion tubes supplement the network of more accurate reference analysers across London.

London boroughs collate and report their data to the GLA and individually publish the results on their own websites.

Here we have collated all the results from the boroughs for 2021 into one data set.

This page will be updated annually with the next year's results.

Technical guidance on the use of diffusion tubes can be found here: