AQEG advice on the use of 'low-cost' pollution sensors

Until relatively recently the vast majority of real-time measurements of air quality in UK were made by established reference methods, using sophisticated analytical instruments that meet well-defined international standards for the quality of the data produced. However, in the last decade there has been rapid growth in the development of low-cost sensors for air pollution measurement and considerable media coverage of these technologies.

We refer in this advice to low-cost sensors which are designed to measure regulated pollutants in ambient air, for which equivalence with European or US reference methods has not been demonstrated, and are often available at lower cost than reference-equivalent instruments. Low-cost in this context can mean many things, ranging from simple single pollutant sensors in units that are sold for a few tens of pounds to relatively sophisticated multi-pollutant devices that include communications and meteorological capabilities and may cost several thousand pounds, but which differ from reference methods because of their compactness, mobility and lower power consumption.

Low-cost sensors are highly attractive for many different reasons – they potentially allow for far greater density of measurements to be made, let individuals measure pollution in their local environment, they may be carried on a person to estimate exposure, or be integrated into networks into local air pollution management systems.

Many different low-cost sensors are being commercialized and the technology and marketplace is evolving very rapidly. For this reason it is difficult for Defra and the Air Quality Expert Group to use its usual format of detailed review reports to provide updates or advice to interested parties on the state of the art. There is a substantial risk that such studies may well be out of date by the time of publication.  

Instead Defra and AQEG will use this part of the UK-Air website to provide regular updates on the science and application of air pollution sensors, their uncertainties and recommendations and advice on where they may, or may not, be appropriate to use. Links to the latest review articles on this subject will also be provided.

A further comprehensive resource for information on air pollution sensors can currently be found on the US Environment Protection Agency website: