Build aerosol traffic light: ESP 8266 warns of aerosols, fine dust and smells Aerosols in the fine dust sensor Olfactory burden Housing made of wood Firmware Measured values interpret Article in c’t 3 / 2021 read Aerosols are on everyone’s lips. Unfortunately. The tiny droplets also transport coronaviruses and are therefore for most infections with Covid – 19 indoors. Frequent ventilation will help keep the concentration of the droplets down. Unfortunately, you quickly forget to open the window and the potentially contagious droplets accumulate. A sensor that measures and warns could remind you of this.

Unfortunately, there are no sensors that measure aerosol concentrations directly . This is why aerosol experts often recommend CO 2 – Sensors to monitor the indoor air. In a room with few plants, the CO 2 – Concentrations increase when aerosols accumulate through breathing air. The Make has built a very cheap CO2 sensor that starts from 1000 ppm warns. This is the current limit value recommendation of the Federal Environment Agency.

Even if CO 2 and aerosols in most cases strongly correlated there is still no evidence that just 1000 ppm CO 2 represent the magical limit below which there is no corona – there are contagions. The results of a joint research paper by aerosol experts show that a critical amount of droplets can accumulate within minutes. Knowing whether there are more aerosols floating in the room than usual would help despite all the ignorance of the exact limit values.

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