Micro air quality sensors have gained great popularity in recent years. However, are they reliable and the data robust? The CITI-SENSE consortium has published an article about an evaluation toolkit for such air quality devices: Fishbain B et al (2016): An evaluation toolkit of air quality micro-sensing units. Science of The Total Environment. http://dx.doi.org/10.1016/j.scitotenv.2016.09.061.