Before and After



Rogues Gallery

Free Health Check


Bad NO2

Free Calibration Spreadsheet


 Rogues Gallery


Here is a collection of hourly mean timeseries plots showing a range of data anomalies. These data were downloaded directly from public web sites. Recent data are obviously provisional, even if not labelled, and subject to further quality control. Some data were provided as final data and were already used in reports. The worst examples were from the final reports produced by large reputable environmental consultancies so there is no provisional excuse. Eventually all data should be processed and cleaned up ready for reporting. If the plots look good and convincing, then nobody will know about the internal compromises you have taken to produce your published reports!

Identifying faults is a team effort between the data managers, ratifiers, site owners, calibrators, independent auditors and engineers. Input and insight is welcome from any source. Ultimately, leaving questionable data within final datasets, published reports and websites is the responsibility of the data ratifiers.

All data are anonymous. Plots can be removed on request if you recognise your data.

Open the Rogues Gallery and see the images for yourself.

Should poor quality data remain on public web sites forever?

What does this say about the care and attention of the organisation?

Can any data be trusted?

Not all data are as bad as this PM10 example published by a very well known university. The customer could not see the flat lining and spikes because data was so difficult to plot. The customer assumed / trusted that everything was perfect.

Some common processing inaccuracies and bad practice are shown in the section on NO2.

All is not lost. You just need an expert to diagnose the problem and provide the final polishing. These data just need a little tender loving care. The images in the Before and After section show had bad data can be transformed into a reportable dataset.

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