Measuring Particulate Matter: An Investigation on Sensor Technology, Particle Size, Monitoring Site.

Light-scattering particulate matter sensors can be very inexpensive, but also unreliable. They are often presented as a solution for the creation of dense monitoring networks, offering an alternative approach to mathematical modeling and interpolation techniques applied to data from institutional monitoring stations. The purpose of this article is to study the benefits provided by light-scattering sensors in measuring daily concentrations of particulate matter, when they are used to complement the existing institutional network of high-quality instrumentation. A one-year experiment campaign was performed, placing 56 light-scattering sensors close to an official monitoring station. The effectiveness of the sensors is evaluated by comparing the correlation of the sensors with the official data of the nearby station, with respect to the correlation between the same station and other stations in the official monitoring network. Finally, the different data sources are calibrated on a single reference station, in order to act as predictors of the PM concentration in the point of interest. Estimates are analyzed using root mean square error (RMSE) comparison.