London Air Quality

Introduction

Hourly measurements of indicators of air quality from locations in London are scraped from an API provided by the Environmental Research Group of Kings College London.

The air quality is measured on a pollution index from 1 to 10, with 1 meaning 'low' pollution and 10 being 'very high', according to the descriptors of the air quality bands provided by londonair.org.uk.

Data trends

The mean air quality index in London was range-bound between 1 and 2.2 in the second half of 2018 as shown in the figure below.

The trend in the above graph shows the mean of all station readings and therefore overall pollution reaching a higher value more frequently into winter, as temperatures cool.

There is however little change in the mean value of the air quality in London. This is due to the air quality at each individual site typically having little variation. As an example the site of Holloway Road in North London demonstrates how the air quality index has not moved above 2 since the tool started monitoring the hourly readings.

A look at the mean reading at each site where air quality is measured shows little variation throughout London. Each bar in the blow plot represents a site and the label is the local authority area in which it is located. Sites where the only reading is zero, meaning no data, are excluded from this graph. A value of 1 therefore represents the lowest mean pollution.

The API provides updates to the value of the index based on analysis of the air at about breathing height. The pollutants carbon monoxide, nitrogen dioxide, ground level ozone, particles and sulphur dioxide are monitored in London. More details on the pollutants are available from londonair.org.uk.

Alert parameters

Subscribers are able to change the values of the parameters used in the regular analysis of the data. This gives the subscriber full control of their alerts, which are raised when trends in the data change or exceed the thresholds set, possibly indicating newsworthy events.

To get access to alerts on real datasets or a demo of how subscribers can easily set their own parameters for data alerts use the contact button in the menu bar above.

Sources

The information is obtained from the Environmental Research Group of Kings College London (http://www.erg.kcl.ac.uk), using data from the London Air Quality Network. This information is licensed under the terms of the Open Government Licence.