Air quality dashboard for Highbury and Mildmay
Find out about real-time air quality data from our sensors, including a live data dashboard, as part of an air quality engagement project in the Highbury and Mildmay wards.
As part of an air quality engagement project in the Highbury and Mildmay wards, you can see real-time air quality data from local air quality monitors.
To learn more about the project, give feedback and participate in citizen science workshops or community events visit the project engagement page.
About air quality
Air quality is how clean the air is and how many pollutants (harmful chemicals or substances) there are in the air around us. The more pollutants in the air, the worse the air quality is.
There are three main pollutants of concern:
- nitrogen dioxide (NO2)
- particulate matter less than 10 micrograms in diameter (PM10)
- particulate matter less than 2.5 micrograms in diameter (PM2.5).
Air pollution can affect your health. Find out more about the impacts air pollution can have.
Air quality data for Highbury and Mildmay
Air pollution levels can rise and fall often (fluctuate), so small measurements of data by themselves do not tell you the quality of the air in the borough or what is affecting it. This will be particularly noticeable with the sensors where data is provided real time. A single higher air pollution result does not mean the entire day, week, month or year has poor air quality overall.
It is important to look at pollution levels over the long-term to find trends in air quality, compare results to objectives and identify areas for improvement.
You can find the air quality monitoring data for Highbury and Mildmay by visiting the air quality data dashboard.
Find out more about the two types of monitors we are using.
How to understand the data
There are a number of factors that can affect air quality monitoring results and change how results should be understood. Some of these factors to consider when looking at the results are:
- type and quality of monitor being used
- whether results have been impacted by environmental influences such as weather, changes in pollution outside of the borough or local changes near the monitor
- whether necessary data corrections have been completed to make the data more accurate
- how local results compare to wider changes in pollution and how they can be compared to guidelines on what air quality should be.
While the project is aiming for being as accurate as possible, there will always be some uncertainty because of these factors. You should ready any air quality data with these factors in mind. More information about each of these can be found below.
Monitors we use for Highbury and Mildmay
Diffusion tube monitors
- 35 diffusion tube monitors.
- These small portable monitors measure monthly levels of the pollutant NO2 in µg/m3 (micrograms per cubic metre).
- Some monitors display data back to 2016, while some were installed more recently.
- Data up to the end of 2022 has had data corrections applied. Data from 2023 onwards is uncorrected so may be less accurate.
Air quality sensors
- 12 air quality sensors
- These monitors measure real-time levels of the pollutants NO2, PM10 and PM2.5 in µg/m3 (micrograms per cubic metre).
- These are a newer type of monitor that is larger, less portable and less tested than diffusion tubes.
- These monitors were put up in May 2024 so we have no data before this.
Type and quality of monitor
No monitor is perfect or 100 per cent accurate and while we aim to make the data as good as possible, you need to take the limitations of the monitors and data into account.
In the Highbury and Mildmay wards we are monitoring air quality using two types of monitors.
Diffusion tubes
- These are small tubes with a mesh at the top that is covered in a chemical that absorbs NO2 as air flows over it.
- Provide monthly figures for the pollutant NO2.
- Monitors are changed each month so if there has been an issue with collecting the tube you can have a month where there is no data.
- They are a widely used industry standard monitoring technique used by local authorities across the UK for official air quality monitoring obligations.
- They come with an uncertainty of around +25 per cent or -25 per cent.
- To improve accuracy, we follow a number of national guidelines and apply a range of statistical correction techniques. However, some of these techniques cannot be applied straight away and so real-time data may not show the final, more accurate results.
- More information on these techniques can be found in our annual air quality report.
Air quality sensors
- Provide real time figures for the pollutants NO2, PM10 and PM2.5.
- May have periods of missing data due to issues with collecting or transferring data.
- These sensors are a newer type of monitor and uncertainty levels are less known.
- While they lack an established approach for increasing accuracy, they offer the advantage of monitoring a broader range of pollutants across various locations.
- We are testing their use in this project.
Some of the data on this website for the more recent results is more of an estimate and likely to change when we apply the corrections.
Influences on air quality
There are many different sources of air pollution and factors impacting dispersal of pollution, that can all impact air pollution levels.
Different pollution sources within Islington
The biggest air pollution sources in Islington are:
- road transport
- heating (residential and commercial)
- commercial cooking.
All of these activities release pollutants into the air, contributing to local air pollution.
Different sources from London and elsewhere
Air quality in Islington will also be impacted by pollution sources from outside the borough, from across London and more widely.
Some of these sources will be similar to those in Islington, but could also include natural sources such as sea spray, soil erosion or industrial sources blown in from across northern Europe.
Weather variability over time
Pollution levels can vary over a day, month or year, due to natural changes in weather. For example, still air during high-pressure periods can lead to a build-up of pollution.
Local factors
Building layout affects how air pollution disperses within an area. Urban design, vegetation, and traffic patterns can all play a role.
Due to these many factors it can be difficult to work out what has caused a localised or short-term change in pollution. We tend to consider long-term trends and compare data across a wider area for a more accurate assessment of air quality.
Air quality objectives and guidelines
Though it is impossible to remove all air pollution because of natural sources of pollution, there are air quality objectives and guidelines for an average level of air pollutants to aim for. These objectives are different for each pollutant and period of time. For example, the average level of pollution expected over a year will be lower than average levels that can be measured over a day or hour.
Our map compares the monitored pollution levels to both the annual national objectives and annual World Health Organisation (WHO) guidelines (interim and final objectives).
When comparing a single data point to objectives and guidelines, it is important to remember that these objectives are set for an average over a period of time, with pollution levels within this time period. A single data point above the objective level does not indicate that the objective has been missed.
National Air Quality Objectives (UK)
The UK has national air quality standards, often called air quality objectives, that are scientifically determined levels of pollution that we should not exceed. These are different for each pollutant and period of time.
These objectives also have target dates for when standards should be achieved.
These objectives guide efforts to improve air quality, and protect health and the environment.
World Health Organization (WHO) Guidelines
The WHO provides global air quality guidelines for key pollutants.
These guidelines offer health-based recommendations expressed as long- or short-term concentration levels. Exceeding these levels poses risks to public health.
The WHO also sets interim targets that we should try to achieve on the way to reaching the lowest levels in the guidelines.
Pollutants are:
- Nitrogen dioxide (NO2) - a gas produced mostly by burning of fossil fuels in µg/m³ (micrograms per cubic metre)
- Particulate matter (PM10) - anything not a gas that's less than 10 micrometres in diameter in µg/m3
- Particulate matter (PM2.5) - anything not a gas that's less than 2.5 micrometres in diameter in µg/m3.
| Pollutant | Objective or guideline | Averaging period | Date to be achieved by | Set by |
|---|---|---|---|---|
| NO2 | 200 μg/m3 not to be exceeded more than 18 times a year | One hour mean | 31 December 2005 | National UK target |
| NO2 | 40 μg/m3 | Annual mean | 31 December 2005 | National UK target |
| NO2 | 25 μg/m3 (with iterim targets of 120 and 50 μg/m3) | 24-hour mean | No set date | WHO |
| NO2 | 10 μg/m3 (with iterim targets of 40, 30 and 20 μg/m3) | Annual mean | No set date | WHO |
| PM10 | 50 μg/m3 not to be exceeded more than 35 times a year | 24-hour mean | 31 December 2004 | National UK target |
| PM10 | 40 μg/m3 | Annual mean | 31 December 2004 | National UK target |
| PM10 |
45 μg/m3 not to be exceeded more than 3-4 times a year (with iterim targets of 150, 100, 75 and 50 μg/m3) | 24-hour mean | No set date | WHO |
| PM10 | 15 μg/m3 not to be exceeded more than 3-4 times a year (with iterim targets of 70, 50, 30 and 20 μg/m3) | Annual mean | No set date | WHO |
| PM2.5 |
15% reduction in concentration at urban background locations | Three-year mean | Between 2010 and 2021 | National UK target |
| PM2.5 |
20 μg/m3 | Annual mean | 2020 | National UK target |
| PM2.5 | 15 μg/m3 (with iterim targets of 75, 50, 37.5 and 25 μg/m3) | 24-hour mean | No set date | WHO |
| PM2.5 | 15 μg/m3 (with iterim targets of 35, 25, 15 and 10 μg/m3) | Annual mean | No set date | WHO |
What we are doing with the data
This data is part of air quality monitoring across the borough.
We review this data regularly over time to help us see how pollution is changing. This can help us work out longer term trends, as well as hot spots and impacts of any local or wider projects or schemes. Where we find increases or hot spots, we can then take appropriate action.
We report all of our diffusion tube data every year in our Annual Status Report as part of our statutory duties decided by the GLA and the Department for Environment, Food and Rural Affairs (Defra). We publish reports on our air quality documents page.