The Chippenham Air Quality measurements for June 2025 are now available. The four sensors have now been in place for a year, so we can compare with June 2024.
Rowden Hill
June 2024 – The average PM2.5 particulates for June 2024 was 20.7 ug/m3
June 2025 – The average PM2.5 particulates for June 2025 are 12.1ug/m3.
The air quality is significantly better on Rowden Hill when compared with June 2024.
Though the monthly average is low, there are significant high pollution peaks around the 9th June 2025, as shown in the table below.
| 20 | 2819066 |
2025-06-08 23:37:09 UTC
|
| 18 | 2819066 |
2025-06-09 00:37:09 UTC
|
| 12 | 2819066 |
2025-06-09 01:37:09 UTC
|
| 12 | 2819066 |
2025-06-09 02:37:08 UTC
|
| 12 | 2819066 |
2025-06-09 02:37:08 UTC
|
| 26 | 2819066 |
2025-06-09 03:37:09 UTC
|
| 12 | 2819066 |
2025-06-09 04:39:09 UTC
|
| 38 | 2819066 |
2025-06-09 05:39:09 UTC
|
| 12 | 2819066 |
2025-06-09 06:39:09 UTC
|
| 6 | 2819066 |
2025-06-09 07:39:09 UTC
|
| 60 | 2819066 |
2025-06-09 08:39:09 UTC
|
| 30 | 2819066 |
2025-06-09 09:39:09 UTC
|
| 48 | 2819066 |
2025-06-09 10:39:09 UTC
|
| 62 | 2819066 |
2025-06-09 11:39:09 UTC
|
| 60 | 2819066 |
2025-06-09 12:41:09 UTC
|
| 80 | 2819066 |
2025-06-09 13:41:09 UTC
|
| 68 | 2819066 |
2025-06-09 14:41:09 UTC
|
| 48 | 2819066 |
2025-06-09 15:41:09 UTC
|
| 52 | 2819066 |
2025-06-09 16:41:09 UTC
|
| 26 | 2819066 |
2025-06-09 17:41:09 UTC
|
| 18 | 2819066 |
2025-06-09 18:41:08 UTC
|
| 18 | 2819066 |
2025-06-09 18:41:08 UTC
|
| 18 | 2819066 |
2025-06-09 19:41:09 UTC
|
| 18 | 2819066 |
2025-06-09 19:41:09 UTC
|
| 14 | 2819066 |
2025-06-09 20:43:09
UTC
|
Marshfield Road
June 2024 – The average PM2.5 for June 2024 is 18ug/m3
June 2025 – The average PM2.5 for June 2025 is 14.1ug/m3
Marshfield Road also shows an improvement in Air Quality when compared with June 2024. Though it too shows significant Air pollution around the 9th June 2025, mirroring Rowden Hill. From the 17th to the 26th the batteries were flat!
Langley Road
June 2024 – The average PM2.5 was 15.88ug/m3
June 2025 – The average PM2.5 was 15.1ug/m3
So broadly the same for Langley Road comparing June 2024 to June 2025.
Langley Road continues to show high spikes in Air pollution, including one on June 9th 2025 as per the other sensors. The Langley Road sensor is the only one to exhibit these high peaks. It has exhibited them since install a year and a half ago, and it is unknown what the cause is.
Wood Lane
Unfortunately our Wood Lane Air Quality sensor continues to exhibit intermittent loss of wifi, which the sensor isn’t good at recovering from.
June 2025 – the average was 9.49ug/m3
June 2025 – not enough data
It did however record the period June 9th to 11th, and also showed high air pollution at this point, mirroring the other sensors across Chippenham.
What caused the spike in Air Pollution around June 9th 2025?
Firsty we can look at the air temperature at the sensor to see if that gives any clues?
It doesn’t appear to.
Next we can look at air pressure to see if that gives any information. Air pressure did increase at this point, though it wasn’t the highest of the month.
Checking hstorical wind data didn’t show any significant change in direction or speed.
Does anyone have a suggestion as to what might have caused this blip in Air pollution across Chippenham around June 9th to 10th?
Update on the 9th to 10th June pollution event
We have three possible theories as to what caused the significant increase in air pollution around the 9th to 10th June.
- The A350 dualling work in Chippenham and road closures caused significant traffic diversions. It’s possible this is the cause, though it is unusually for all sensors to be affected by traffic changes. They are usually more localised.
- Canadian Wildfires. Though smoke from the Canadian wildfires did affect the skies in the UK, this article states the smoke is too high an altitude to affect air quality Canada wildfires: What’s the latest? – BBC Newsround
- A landfill wildfire in Calne at this time could also have been the source. Though the wind direction would appear to carry the smoke away from Chippenham, not towards it. Firefighters battle Calne landfill site blaze overnight – BBC News
So we don’t have a definitive conclusion as to what the cause was.