Monitoring

We have air quality monitors in place across Islington measuring some of the main air pollutants of concern:

• nitrogen dioxide (NO2)
• particulate matter less than 10 microgram in diameter (PM10)
• particulate matter less than 2.5 microgram in diameter (PM2.5).

Types of monitors

There are three types of monitors in the borough.

Automatic continuous monitors

We have two automatic continuous monitors - one on Holloway Road and one in Gillespie Park near the Ecology Centre.

• These are the larger and more accurate air quality monitors.
• They operate 24 hours a day and measure two key pollutants: nitrogen dioxide (NO2) and particulate matter (PM10). They provide real-time data on air quality.
• These monitors are commonly used for official air quality monitoring purposes.

Diffusion tubes

There are 22 permanent diffusion tubes spread across the borough. These tubes are placed in a strategic way to best represent typical pollution levels. They allow for long-term monitoring, helping track changes in pollution over time.

There are also around 250 other diffusion tubes placed outside schools, nurseries, care homes, and specific project areas. These tubes provide valuable data on localised pollution.

• Diffusion tubes are smaller and more portable than automatic monitors.
• They provide an NO2 reading once a month.
• While not as accurate as automatic monitors, they are still a nationally recognized monitoring technique.
• Their portability allows them to be deployed across different areas within the borough.

Sensors

We have installed sensors in the Mildmay and Highbury wards as part of an engagement scheme. These sensors complement the existing 35 diffusion tubes in the area.

• Sensors also measure NO2, PM2.5 and PM10 continuously, similar to automatic monitors.
• They are smaller and more portable than automatic monitors but larger and less portable than diffusion tubes.
• However, the accuracy of some sensor-based monitors is not well understood. This means that they cannot be used for statutory monitoring duties and official reporting.

At our request other organisations may also use other monitors to carry out pollution monitoring such as dust monitoring at construction sites.

Monitor locations

This comprehensive monitoring network ensures a better understanding of air quality trends and us decide what we need to do to improve the air quality for residents.

The exact locations of our automatic monitors and diffusion tubes can be found in our annual air quality report.

The location of the sensors deployed in Highbury and Mildmay wards are:

• Balls Pond Road
• Boleyn Road
• Brownswood Road
• Green Lanes
• Grosvenor Avenue
• Highbury Park
• Highbury New Park
• King Henry’s Walk
• Mildmay Park
• Newington Green
• Newington Green Road
• St Paul’s Road

Where to find monitoring results

The results of all of the diffusion tubes and the automatic monitors are published each year in our Annual Status Report and support the ongoing review and assessment of air quality in the borough. The latest annual report can be found on our documents page.

Results of the sensors and diffusion tubes in the Mildmay and Highbury wards will be found on the project website when it’s launched.

You can find results from the two automatic monitors can also be found on the London Air Quality Network website.