Latest air quality data : Dashboard : Lewis

You can download the data for Lewis in CSV format via the link below:

Data Quality Statement

The network’s aim is to provide measurements of pollutants which may affect human health, namely particulate matter (PM10 and PM2.5) and sulphur dioxide (SO2). SO2 is measured using UV fluorescence analysers operated to a procedure based on BS EN 14212:2012.

Tulloch Bridge & Lewis: PM2.5 and PM10 are measured using a MCERT indicative ambient particulate monitor (certified for PM10).

Orkney & Loch of Strathbeg: PM2.5 and PM10 are measured using a FIDAS 200 which holds MCERTS for UK Particulate Matter certification.

The ‘latest data’ displayed undergo some basic automatic screening, therefore the data may be subject to change when evaluated during the follow up verification and ratification procedures.

The verification and ratification procedures for the data are designed to maximise the quality of the data.

Data verification is carried out on an ongoing basis. The verification procedure may:

  • remove anomalous data caused by instrument malfunction or faulty calibrations
  • add missing data lost due to communications failures
  • scale data based on latest calibration data or manual certified gas checks

Any corrections to the data made during the verification process are automatically uploaded to the 7 and 30 day graphs and the downloadable CSV datasets. It should be noted that the data at this stage are still provisional and may be subject to further changes. Provisional data are marked with a P.

Data ratification is a detailed manual check of the data set carried out on a quarterly or six-monthly basis. The data ratification process assesses, and if required corrects, data based on:

  • all calibration data
  • analyser performance
  • certified gas standards
  • site records
  • audit findings
  • known interferences, pollution episodes/patterns and long term trends

Once all the verification and ratification checks have been completed the data are re-loaded to the downloadable CSV files with a ratified status mark of R.

Site information : Isle of Lewis
58.21429271, -6.39729669
A largely rural location within the Lews Castle College campus, 1km to the west of Stornoway. Marybank Quarry lies 800m to the south west and Stornoway harbour lies approximately 1km to the south east of the monitoring station.
SO2 / indicative PM2.5 and PM10 / Wind speed and direction.