Air quality monitoring and data

See the air quality results for today.

These results are for the continuous monitoring in the borough. Our mobile unit was stolen in August 2020 and will be replaced with a site in Richmond town centre early in 2025.

The most recent annual bias-adjusted results for the 67 long-term diffusion tubes which record nitrogen dioxide (NO₂) across the borough can be seen on our online map. You can view average annual concentrations for each year by clicking on the small boxes to the left of the map one at a time.

Tables of these data can be found in our latest annual status report. The use of additional diffusion tubes is detailed below.

Full bias adjusted results for 2024 will be available from August 2025 in our 2025 Annual Status Report once it is approved by the GLA.

All results for Air Quality Monitoring from 2005 to 2023 can be found in our Annual Air Quality Reports.

Historical data from the continuous analysers can be found below.

Increasingly it is thought that high levels of air pollution are detrimental to health, especially for susceptible members of the community, such as the elderly, children, asthmatics and individuals with bronchitis and other respiratory complaints. It is important to us that we ensure pollution levels are regularly checked.

We monitor local air quality using both continuous analysers and diffusion tubes.

NO₂ diffusion tubes

Diffusion tubes are a useful, low cost way to monitor nitrogen dioxide borough-wide. In addition to the 67 long-term diffusion tubes, we use NO₂ diffusion tubes to gather air quality data which helps inform planning proposals and traffic management decisions, such as the Royal Parks Movement Strategy and proposed Low Transport Neighbourhoods (LTN’s) in the borough. A proposed LTN in East Sheen was dropped and an LTN in Hampton Hill was made permanent, partly with the help of air quality monitoring data. Diffusion tubes are also used for short-term monitoring 24/7 for a month or more where residents have concerns, including outside schools.

In January 2022 we began a three-year programme to monitor worst case scenario 24/7 for a full year outside all state primary schools within the borough. This monitoring was completed in January 2025.

The diffusion tube results can be viewed on the following pages:

• Nitrogen dioxide results - diffusion tube sampling
• Benzene results - diffusion tube sampling
• Polycyclic Aromatic Hydrocarbon results - diffusion tube sampling

Continuous analysers

Monitoring of air quality in the borough takes place 24 hours a day. We currently have two static monitoring units. These are located:

• Outside Castelnau Library
• At London Wetland Centre

Continuous monitoring of the following pollutants is carried out:

• Nitrogen dioxide NO₂
• Ozone O₃
• Carbon Monoxide CO
• Particulate matter:
  • PM₁₀
  • PM_2.5

View the latest air quality results.

Historical monitoring

You can also view older air quality monitoring data.