Sampling of Surface Dust in Buildings

Abstract

IntroductionSurfaces affect the indoor environment quality. By acting as sources and sinks for air contaminants they influence exposure of the room occupants. Moreover, surfaces and their contaminants affect the visual impression of the rooms. The degree to which the amount of surface dust affects the indoor environment needs to be assessed by quantitative measurements. This chapter begins with presenting a simple conceptual model including the compartments and transport processes that ultimately lead to exposure of room occupants by inhalation, ingestion, dermal uptake, or by visual perception. The model is then used to structure the presentation of measurement principles. Sources of variability in surface dust concentrations are listed that need to be known in order to design cost-effective sampling strategies. Finally, specific sampling methods are described. It has been the intention in this chapter to present key elements of surface dust sampling, which the investigator can use to design a sampling protocol for a particular task. For details of the quoted methods, the reader is referred to the original papers. Aspects of sampling that are specific for microorganisms, such as use of agar contact plates, are not covered.Surface contaminants may consist of dirt, loose dust, strongly adhering particles, and "greasy" matter, as well as adsorbed vapors. For simplicity, this entity will be termed dust, unless specified otherwise. 2.3.2 The ScenarioThe contribution of surface dust to the indoor environment quality can be viewed from different angles, defined by the question asked. Surface dust can be viewed, e.g., as:Reflecting what has been in the air averaged over the time period since the surface was cleaned. A secondary source of airborne particles if agitated. Indicating efficiency of last cleaning and recontamination rate. 82 2.3

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