Using MQ135 (or similar) to sense dust particles in PM

I was building a Air-purifier system. So, I need to monitor dust particles present in the air. Is it possible to use a gas sensor like the MQ135 to sense dust particles? Since, It can sense very small gas particles. Would it be possible to sense dust particles with it(MQ135 {Cheaper to buy}) or I need to buy a special optical dust sensor {Costly!}

  • You class this as costly?
    – Majenko
    Mar 9, 2017 at 18:28
  • @Majenko: i class that as very expensive; easily 4X the 2nd cheapest part in a build, when gas sensors are only a buck or two... it's hard to get a build out the door for $10-20 if a part cost $15...
    – dandavis
    Mar 9, 2017 at 20:54

1 Answer 1


The MQ sensors can not be used to sense dust particles. They are Electrochemical gas sensors which are sensitive for certain gasses. They are not sensitive for dust particles. Dust is not a gas, but tiny solid particles.

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