Indoor air pollution system based on LED technology

Indoor air quality requirements are a hard constraint for workers’ rooms and close locations, and many legislations require frequently measurements for safety. In presence of possible leaks and room climate deterioration, it is required a permanent and online measurements by means of appropriate instrumentation. For hospital rooms, and in particular for surgery rooms, air monitoring of gaseous components is mandatory. In general, there are two main techniques: photo-acoustic spectroscopy (PAS) and chromatography. The first is a portable instrument for quick monitoring even if it is accurate. The latter is not a portable instrument but it is for sensitive and accurate measurements. The paper proposes an architecture of measurements, based on LED spectroscopy for monitoring surgery rooms. In particular, it illustrates the control system based on pulse width modulation. Since the architecture is not PAS and it is not based on chromatography, it could not monitor a large number of pollutants. But conversely, it would be able to measure with high accuracy a small number of chemical species included in pollutants. We only report a deep analysis and experimental activities of control systems.