Bests & Worsts Reviews from Amazon

This air quality monitor works very well for it's stated purpose. Something that is not clear and many reviewers may not know is that the displayed AQI calculation only takes PM 2.5 (smaller sized particles) into account. So it is possible that you are in an environment where you have high levels of PM10 particles (that would indicate poor air quality) but low levels of PM 2.5 particles and the Air Visual Pro would indicate a good air quality AQI. So this may explain why some reviewers perceived this as a symptom of a faulty monitor. The AirVisual Pro does have a PM10 sensor and does capture that measurement separately. You can access PM10 and PM2.5 measurements via a computer for offline analysis. Given that the PM10 measurement is available, I dont understand the rationale for not including it in their displayed AQI calculation. It would seem that all it would take would be a simple software change. This is the reason I took one star away from this product. Otherwise, it seems very accurate for PM 2.5, PM10 (checked offline), and Carbon Dioxide. You can google reviews for the AirVisual Pro and you will find many websites and organizations that have put this monitor to the test against similar products and in general they give the AirVisual Pro high marks. That has also been my experience as well, this monitor is very sensitive (including detecting increase in particles due to cooking, sweeping, using oil diffusers, etc...). I really would like them to update their software to include PM10 in their AQI calculation as well as later add an Ozone sensor.