Monitoring and reporting on air quality

London has one of the most comprehensive air quality monitoring networks in the world. It measures pollution using a variety of monitors. These include high-precision reference monitoring stations, diffusion tubes that track long-term trends and the community-based Breathe London network providing local, street-level insights.

Londoners can use the air quality dashboard to explore detailed air quality data for their local area and across the city.  

This dashboard compiles data from three types of air quality monitors: 

• Reference data. This uses high-accuracy air quality monitoring stations owned and operated by London’s boroughs, providing hourly measurements. This uses data gathered through The London Air Quality Network and Air Quality England. 

• Breathe London and Breathe London communities.  These communities are a collaborative network of low-cost sensors, integrated with the reference network to enhance data quality and accuracy, providing hourly averages for nitrogen dioxide (NO2) and fine particulate matter (PM2.5). 

• NO2 diffusion tubes. These are low-cost, indicative sensors deployed by London's boroughs. They provide monthly average NO2 concentrations. Data from these sensors are published in London borough Annual Status Reports and summarised in the GLA’s Air Quality Compendium.  

We've published a number of reports which analyse data from these air quality monitors. Find them on our Environment and Climate Change publications page.