Information about the pollutants we monitor in the borough
Pollutants and monitoring methods
Air pollutants are emitted from a variety of both natural and man-made sources. Many everyday activities can have a negative effect on air quality, with an impact on human health, such as from:
- traffic
- burning fossil fuels
- farming
- industry
The pollutants we monitor in ambient air are:
- Nitrogen Dioxide (NO2)
- Particulate Matter (PM10 and PM2.5)
We review the concentration/levels of these pollutants within the borough against National Air Quality Objectives.
Nitrogen Dioxide
Air Quality Monitoring Stations
We have automatic pollution monitoring stations at the following locations:
- South Gates Park, King's Lynn
- Gaywood Clock
Southgates monitoring station
These sites measure NO2, mainly from road traffic and background sources.
Diffusion tubes
These are small plastic tubes that contain a chemical that reacts with NO2. They provide us with an average concentration of NO2 in the air.
Sources of NO2 include:
- traffic
- combustion of fossil fuels
- industrial processes
There are currently 72 sites with NO2 diffusion tubes located across the borough. The tubes are usually placed on the front of buildings near a busy road, or at road junctions.
We change these monthly and get them analysed.
The monthly average NO2 level is used to calculate a yearly average. We then compare this to the annual mean objective level as set in the National Air Quality Objectives.
Image of a diffusion tube
The results are used, with other data, to compile yearly air quality reports called Annual Status Reports. These are submitted to the Department for Environment, Food and Rural Affairs (Defrade). You can view these reports on our air quality information page. They include a summary of the results from each year and trends in the pollutants that we monitor.
Particulate Matter
Particulate Matter within the size fractions of less than 10 and 2.5 microns (PM10 and PM2.5) is measured automatically by 4 indicative analysers (Turnkey Osiris units) at the following locations within the borough:
Image of an OSIRIS unit
- Estuary Road, King's Lynn
- Page Stair Lane, King's Lynn
- Wretton Road, Stoke Ferry
- Buckenham Drive, Stoke Ferry
The PM10 and PM2.5 that we monitor for is primarily associated with local industrial sources centred around the docks and an agricultural feed mill.
COVID-19 and air quality trends
Following Covid epidemic we have seen a dramatic decline in traffic resulting in around a 20% reduction in NO2 levels for the 2020 period when compared to the pre-Covid 2019 year. The concern however is any return of traffic (and NO2) similar to pre-Covid period for which we continue to monitor.
Viewing our data
The monitoring data collected from the automatic stations is available to view in real-time from our data management website that also includes results from neighbouring local authorities.
Or you can download the UKAir app available for both apple and android.