Hi there:
calculations. The meaning of “duration = pulseIn(pin, LOW)” in Arduino is: <LINK_TEXT text=“https://www.arduino.cc/reference/en/lan … o/pulsein/”>https://www.arduino.cc/reference/en/language/functions/advanced-io/pulsein/</LINK_TEXT>
In addition, sensors measure a variety of particulate matter, not just PM2.5. So its result does not represent the concentration of PM2.5.