This work is related to development of a new type of fog sensors and measurement devices. We study fogs, their properties, and especially their ability to clean different contaminants from the air, such as chemical, biological, radiological and nuclear (CBRN) agents. In that sense, fog can be used for effective counteraction to terrorist attacks and for prevention of industrial accidents and disasters. In this paper, we present the possibility for measurements of fog parameters using the Surface photo-charge effect (SPCE) and some results obtained in that way concerning size and speed of droplets. Knowledge of these fog parameters is important in order to gain a more practical insight about the optimization of the penetration and cleaning properties of fogs used for large scale decontamination.