Low-cost air pollution sensors are an exciting opportunity for atmospheric chemistry research and are a potentially disruptive technology for air pollution monitoring. Mid June, the Scientific Advisory Group on Reactive Gases of the Global Atmosphere Watch (GAW) Programme issued an advisory note aimed at users considering adopting sensor approaches for air pollution measurements. It identifies some of the basic technologies, key operational factors and possible deployment scenarios.
The benefits of using sensors are clear: they may allow many new observations to be made economically with high spatial densities and provide a means to track human exposure to air pollution when carried on a person. However, there is a growing body of literature that shows that sensors can be prone to cross-interferences from other atmospheric pollutants, are very sensitive to environmental variables, such as temperature and humidity, and have untested medium and long-term stability. They are also difficult to calibrate using existing reference materials. It is, therefore, essential that users of low cost sensors validate that performance meets the technical requirements of specific applications.
The applications where air pollution sensors could be used are many, ranging from the support of air quality regulations through to purely indicative measurements of pollution in general terms. It is important that the analytical requirements of each application are matched against the proven capabilities of any given sensor device. Since the variety of sensors on the commercial market is wide, there is no straightforward answer to the question “what can sensors be used for”? This must be established by the user on a case-by-case basis.
The GAW advisory note, which can be accessed at the main page of the programme www.wmo.int/gaw, offers a generalized set of recommendations on sensors use for different applications.