PM#nbsp;2.5 fine dust particles are probably the most popular air contaminant in#nbsp;the world, a#nbsp;pop star among city air pollutants. Firstly, it#nbsp;is#nbsp;widely known to#nbsp;be#nbsp;very hazardous for human health. Secondly, thousands of#nbsp;models of#nbsp;fast-food sensors have recently appeared on#nbsp;the market, measuring something like#nbsp;PM 2.5, so#nbsp;it#nbsp;seems that concentrations of#nbsp;particulates can be#nbsp;easily monitored.