An optical sensing system for atmospheric particulate matter

Atmospheric particulate is one of the main responsible for the environmental pollution of highly populated cities. The particulate matter can be considered an aerosol of many particles, with different shapes, morphologies and sizes down to few micrometers. These small particles are responsible for climate changes and, when inhaled, can reach the lungs causing respiratory and cardiovascular diseases. Usually commercial sensors are based on passive filters and are designed to measure only particles whose size is below a certain value. Therefore, a measuring system capable of assessing the quality of air and evaluating not only the amount of particles, but also the size distribution of the particulate matter in urban atmospheres could be extremely helpful. This paper describes a simple and cheap optical solution, which is able to detect the total amount of solid pollution particles and classify them according to their average size, giving a fast response to the users.