Beta attenuation monitoring (BAM) is a widely used air monitoring technique employing the absorption of beta radiation by solid particles extracted from air flow. This technique allows for the detection of PM10 and PM2.5, which are monitored by most air pollution regulatory agencies. The main principle is based on a kind of Bouguer (Lambert–Beer) law: the amount by which the flow of beta radiation (electrons) is attenuated by a solid matter is exponentially dependent on its mass and not on any other feature (such as density, chemical composition or some optical or electrical properties) of this matter. So, the air is drawn from outside of the detector through an "infinite" (cycling) ribbon made from some filtering material so that the particles are collected on it. There are two sources of