Causes of Sampling Measurement Uncertainties when Determining the Particle Concentration in a Gaseous Environment

Measuring particle concentrations is very important in many applications; this has been particularly so since the 1960s, when their harmful influence on human health was proved. Measuring particle concentrations has a much greater measurement error than when measuring the emissions and/or immissions of other pollutants in the field of air-quality protection. Viewing the peculiarities of particles within the group of air pollutants, the elaboration of general standard specifications for emissions and/or immission quantities in the case of particles requires an approach to one of the two contradictory and extreme simplifications: the gas-particle system is either viewed in terms of a continuous environment or as a set of discrete particle trajectories in a gas. Due to the limitations of the available measurement procedures the result in both cases is the presentation of the mean value of the mass flow density as a product of velocity and concentration mean values, implying in advance a measurement error. In this paper attention has been focused on the sampling characteristics during the determination of the particle concentration, which are the main sources of measurement uncertainty, and on the limitations of their elimination in practice.