LAQN Pollution Levels


  Ozone Nitrogen Dioxide Sulphur Dioxide PM2.5 Particles PM10 Particles
Period Running 8 hourly mean Hourly mean 15 minute mean 24 hour mean 24 hour mean 24 hour mean
Units µg m-3 µg m-3 µg m-3 µg m-3 µg m-3 µg m-3
Exceedance point 100 200 333 20 35 50
For pollutants with only daily limits (PM10, PM2.5, O3), we have used the same trigger system which is used to predict levels for the UK Daily Air Quality Index. The WHO SO2 Guideline is specified as a ten minute mean, but our instruments are set to take 15 minute measurements. We have converted the WHO 500 ug/m3 ten minute mean into the equivalent 366 ug/m3 15 minute mean, and are reporting to this in line with the recommendations of the UK Expert Committee on Air Quality Standards. Please note that the PM2.5 Guideline for the UK has been determined using the UK average PM2.5:PM10 ratio of 0.7, as per the WHO guidance, rather than the 'global' ratio of 0.5 which is indented for developing countries. For UK conditions this means that the daily WHO Guideline for PM2.5 is 35ug/m3.

Air pollution levels for Wednesday 30 July 2014, 14:00-15:00BST

Low (1-3) Moderate (4-6) High (7-9) Very High (10) Predicted No Index Closed
Low
(1-3)
Moderate
(4-6)
High
(7-9)
Very High
(10)
Predicted No Index Closed

How is the Air Pollution Index calculated?     Switch to Static Map

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This map shows the daily air quality index from LAQN pollution analysers. Not all analysers on the network are contacted every hour, so some sites may show 'no data'. Data have undergone automatic validity checks.
You can find out more information about each location (monitoring site) by clicking on its dot on the map. Once selected you can find out further information by clicking the 'Site Details' link above.

Click the 'Statistics' link above to see results from this site compared to national limit values. Past pollution episodes can be seen by clicking on the 'Episodes' link.

Alternatively, click on the button below to see a graph of this week's pollution levels.
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