Indoor material samples

Indoor Material Samples Containing SVOCs/POMs... 

Recent studies have revealed that carbon tetrachloride is also a common contaminant of indoor air. Typical concentrations in homes in several U.S. cities were about 1 pg/m (0.16 ppb), with some values up to 9 pg/m (1.4 ppb) (Wallace 1986). Concentrations in indoor air were usually higher than in outdoor air, indicating that the source of the carbon tetrachloride was building materials or products (pesticides, cleaning agents) inside the home (Wallace 1986 Wallace et al. 1987). Based on 2,120 indoor air samples in the United States, the average concentration of carbon tetrachloride was 0.4 ppb (2.6 pg/M) (Shah and Heyerdahl 1988). However, the median value was 0 ppb, indicating that carbon tetrachloride was not detected in more than half the samples. 

The information gained by application of odor evaluation and odor analysis of indoor environment and material samples not only serves the purpose of knowledge accumulation, but can also be used as a tool for air quality and product improvement. The combination of the two methods has the potential of a systematic approach to developing odor optimized technical materials. One example is given here. 

Pentachlorophenol concentrations in urine and serum can be used as biomarkers of internal dose (Colosio et al., 1993a). PCP concentrations up to about 30 mg/L were detected in urine samples of exposed workers, while concentrations lower than 0.3 mg/L were detected in the general population. The presence of PCP in biological samples of the general population is attributable to indoor exposure to the compound released from treated materials (furniture, leather, paints, etc.). 

ASTM. 1991. Standard practice for sampling and analysis of pesticides and polychlorinated biphenyis in indoor atmospheres. American Society for Testing and Materials. ASTM designation D4861-91. p366-379. 

Because of volatilization and leaching from their application in consumer and personal care products, phthalate esters are ubiquitous contaminants in indoor environment, and the levels found in dust from homes in different countries (Table 2), showed that the less volatile phthalates such as DEHP and BBP, are the predominant in dust samples [11,16, 74], and that the percentage of both carpet and plastic materials (furniture, decoration, and home electronics) could be associated with higher concentrations of BBP and DEHP in house dust [12, 74, 75]. The proportion of DiNP in house dust from Germany in 2009 [12], indicates that the... 

The use of building materials, furniture, carpets and household products produces an almost ubiquitous level of volatile organic compounds (VOCs) in indoor air. Several hundred different compounds have been identified in the indoor environment. Since most air pollutants occur in low concentrations of 1-1000 rg/m3, highly sensitive detection methods as well as efficient separation methods are needed to analyze air samples (Barro et al., 2009). 

All kinds of building materials, furniture, textiles, computers etc. are potential sources of SVOCs/POMs and estimation of the total content in the material may be required. One reason to estimate the total or initial content is that it is an important parameter in physical based emission models for example, for phthalate emission from vinyl flooring (Clausen et al, 2007). The materials can be purchased as new, or sampled from the indoor environment under investigation. The materials should be stored in a way that preserves their content of SVOCs/POMs and prevents contamination and degradation of the materials and their content of SVOCs/POMs. The content of SVOCs/POMs in the sampled materials can be estimated by extraction (see Section 2.5.1). 

Evaluation of VOC and SVOC emission potential of individual products and materials under indoor-related conditions and over defined timescales requires the use of climate-controlled emission testing systems, so-called emission test chambers and cells, the size of which can vary between a few cm3 and several m3, depending on the application. In Figure 5.1 the dots ( ) represent volumes of test devices reported in the literature. From this size distribution they can be classified as large scale chambers, small scale chambers, micro scale chambers and cells. The selection of the systems, the sampling preparation and the test performance all depend on the task to be performed. According to ISO, chambers and cells are defined as follows ... 

Air quality-Sampling and analysis of VOCs in ambient, indoor and workplace air (and small and large-scale materials emission chambers) by sorbent tube/ thermal desorption/capillary gas chromatography. Part 1 Pumped sampling. 

Conventional materials emissions test methods are usually carried out using small test chambers or cells with samples prepared and presented to the air flow within the chamber/cell as they would be to room air in real use. Operating parameters (temperature, humidity, etc.) are selected to simulate the indoor environment and are summarized in Table 6.2. 

In the indoor environment, sources that can contribute to the VOC levels include building materials, occupants and their activities, ventilation systems and outdoor vehicular combustibles (Daisey et al., 1994 Molhave and Thorsten, 1991). Computations of indoor-outdoor ratios are frequently used to conclude indoor or outdoor sources (Daisey et al, 1994). Generally, derived findings originated from these samples collected when the ventilation systems were in operation. It is difficult to determine the major source of VOCs for the buildings studied because contributions from building materials, occupants and their activities, ventilation systems and outdoors are all present together. 

Haumann, T. and Thumulla,). (2002) Semi volatile organochemicals in indoor environment-chlorinated phosphorus and organotin compounds in material und house dust samples. Proceeding of Indoor Air 2002(4), pp. 865-70. 

Materials. All paper samples were cut from a continuous length of machine-made rolls. Two different papers have been studied. One is a bleached Kraft wood pulp waterleaf (50-lb basis weight) made by Neenah Paper Mills from a stock that comprised northern softwoods (60Z) and Lake States hard woods (40J), and contained no additives. The second paper, Foldur Kraft, is a bleached Kraft paper (70-lb basis weight) made by Champion Paper Company from a stock of 90Z softwoods and 10Z hardwoods, with alum-rosin size and 8Z titanium dioxide filler. This paper was obtained 15 years ago. Since then it has been stored indoors in areas which have not enjoyed a carefully regulated environmental control. 

Figure 12 Plot comparing calculated saturation indices of various minerals of interest in SLF blank, and filtered (<0.45 p,m) SLF leachates of an indoor WTC dust sample (WTC-20) and outdoor WTC dust sample (WTC-16). The extreme supersaturations in the WTC dust leachate samples may result in part (but not entirely) from inclusion of some colloidal material less than 0.45 p,m in size in the analyzed filtrate.

Compared with whole air sampling into Tedlar bags and canisters, active sampling onto sorbent materials is used more widely in these indoor air quality (lAQ) studies. Only a few studies made use of organic vapour monitor passive samplers. Of the sorbent materials used, Tenax is the most frequently employed, possibly because of its virtues, which are mentioned in Sect. 4.2.1. It has been used for the characterisation of aromatics, alkenes, cycloalkanes, aldehydes, ketones, esters, alcohols, terpenes, glycol derivatives and even amines [33,59]. 

The most common method of evaluating indoor sinks involves placing a sample of the sink material in a chamber and then flowing a fixed concentration of challenge gas through the chamber at a known flow rate. This is shown schematically in Fig. 1. 

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