Significance and Use
5.1 Diffusive samplers provide a useful sampling option for studying time-weighted average indoor air concentrations of vapor-phase pollutants. They are easy and cost-effective to deploy enabling the collection of relatively large data sets.
5.2 The objective of this guide is to provide guidance for the placement and use of diffusive samplers that when uniformly applied enables the user to eliminate many potential interferences that may occur in diffusive sampling of indoor air. Since the analysis of the indoor environment by diffusive sampling is influenced by many factors other than the method of sampling, efforts are made to minimize interfering factors and maintain the air at conditions typical of the measurement location within the vicinity of the diffusive sampler. However, when performing certain diagnostic or special measurements, non-typical indoor air environmental conditions may be desirable or required. Thus, the objectives of a sampling study determine the conditions needed for sampling.
5.3 Diffusive sampling provides for time integrated measurements. Diffusive samplers are usually placed in an indoor environment over a time period to obtain a time weighted average concentration; hence, interfering factors potentially occurring over this period should be anticipated and eliminated where possible. Diffusive samplers often lack the sensitivity to measure short-term peak concentrations.
5.4 With suitable instruction regarding placement of diffusive samplers, placement, and retrieval of the samplers can be performed by unskilled personnel (for example, occupants).
Scope
1.1 This guide covers the placement and use of diffusive samplers in an indoor environment.
1.2 The primary use of diffusive samplers is to measure the exposure concentrations of specific gaseous air contaminants for occupants in a variety of indoor environments.
1.3 Diffusive samplers within this guide are used to measure concentrations of air contaminants in residences, public buildings, offices, and other non-industrial environments. A diffusive sampler is any air sampler that does not utilize electrical or mechanical power in order to supply air to the sorbent media or chemical reactant within the sampler and that samples according to Fick’s first law of diffusion.
1.4 The purpose of this guide is to ensure uniformity of sampling within a variety of indoor environments and to facilitate comparison of results.
1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.7 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.