Since the inhalation of fine dust impairs human health EU guidelines 1999/30/EG and 2008/50/EG define maximum permissible values of the PM10and PM2,5 mass fractions, which must be monitored continuously. For Palas®, market leader in optical aerosol spectrometers, it was therefore the obvious thing in 2010 to develop an optical real time fine dust analyzer technology superior to conventional monitors – the Fidas® fine dust monitor systems. These provide measurement of PMtotal, PM10, PM4, PM2,5, and PM1 as well as the particle number concentration Cn simultaneously and in real time. Furthermore the respective particle size distribution in the range between 0.18 and 18 µm is determined at any moment in time. All fine dust analyzers of the Fidas®200 system are type approved and certified in compliance with standards EN 12341, EN 14907, EN 15267, and EN 16450.