Visual Response to Dustiness

Abstract

Dustiness is a visually perceived phenomenon. In this paper, results of a quantification experiment for dustiness using a photometric method of measuring dust deposition and panel sampling techniques are reported. It was found that with maximum contrast a 0.2% effective area coverage (EAC) by dust can be perceived against a clean background. The minimum perceivable difference between varying gradations of shading was a change of 0.45% EAC. The results also revealed that a dust deposition level of 0.7% EAC was required before the object so covered was deemed unfit to use. A telephone survey indicated that the minimum tolerable interval between household dusting was every four days. Combination of the telephone survey information with the level of dust coverage found to be objectionable implies that a dustfall rate of less than 0.17% EAC/day would be tolerable for the population at large.