Indoor contamination

Direct control A sy.stem controlled by a sensor that detects levels of indoor contaminants within the space... 

Contaminants Indoor contaminants are expected to compete for adsorption sites on the charcoal. We will experimentally find the effect that these contaminants have on the dynamic adsorption coefficient and on the life-time of the charcoal bed. Since the number of radon atoms in even the most seriously contaminated houses is very small, decay product buildup is not expected to pose a significant problem. 

Harrad S, de Wit CA, Abdallah MAE, Bergh C, Bjorklund JA, Covad A, Damerud PO, de Boer J, Diamond M, Huber S, Leonards P, Mandalakis M, Oestman C, Haug LS, Thomsen C, Webster TF (2010) Indoor contamination with hexabromocyclododecanes, polybrominated diphenyl ethers, and perfluoroalkyl compounds an important exposure pathway for people Environ Sci Technol 44 3221-3231... 

Rodes, C. E., R. M. Kamens, and R. W. Wiener, The Significance and Characteristics of the Personal Activity Cloud on Exposure Assessment Measurements for Indoor Contaminants, Indoor Air, 2, 123-145 (1991). 

VVOCs, (b.p. <0 to 50-100°C) and VOCs, (b.p. 50-100 to 240-260 °C) are transitory and predominantly found in air. Organic compounds of lower volatility, that is, SVOCs (b.p. 240-260 to 380-400°C) are present in air as well as in dust, whereas POM (b.p. >380°C) is part of the dust indoors. Analyses of SVOCs in indoor air and house dust are a measure of indoor contamination but may also provide valuable information for the assessment of human indoor exposure. 

The contradictory results may be due to different contamination levels. With a high indoor contamination it might be easier to detect an association, whereas with low indoor contamination levels associations may be hidden by the ubiquitous presence of the biocide and dietary intake. Taking DDT as an example, that formed much higher residues in house dust 30 years ago, it was stated in 1975 that the contamination of house dust by the domestic use of DDT was primarily responsible for human serum residues (Davies, Edmundson and Raffonelli, 1975). 

Indoor air is an ideal material to get information about the actual exposure via inhalation. House dust, on the other hand, as a measure of indoor contamination, is easily accessible, compounds are stable, shipment is simple and concentrations are high compared with air. 

Butte, W. and Heinzow, B. (2002) Pollutants in house dust as indicators of indoor contamination. Reviews of Environmental Contamination and Toxicology, 175, 1-46. 

Rodes, C., Kamens, R. and Wiener, R.W. (1991) The significance and characteristics of the personal activity doud on exposure assessment measurements for indoor contaminants. Indoor Air, 1, 123 45. 

In addition to the magnitude and number of potential sources, a number of factors can influence levels of indoor contamination. In the first instance, the relative ease with which different classes of POPs can undergo emission from products within which they are incorporated will influence indoor contamination. For example, while the production volume of TBBP-A far exceeds that of HBCD (BSEF, 2001), TBBP-A is present in far lower concentrations than HBCD in indoor air and dust (Abdallah et al., 2008). Abdallah et al. (2008) attributed this observation to the fact that the principal use of TBBP-A is as a reactive flame retardant, whereas HBCD is used as an additive flame retardant. While... 

Fuller details of the applications of PFCs may be found in Chapter 3. The database on indoor contamination with these chemicals is to date less comprehensive than for either PCBs or PBDEs, but summaries of concentrations of selected PFCs in both indoor (and outdoor) air and indoor dust are given as Tables 7.7 and 7.8. 

The previous section demonstrates clearly that concentrations of the POPs under consideration in this chapter are markedly higher in indoor air and dust than those detected in the corresponding matrices (air and soil respectively) outdoors. It is therefore pertinent to evaluate the significance of human exposure that arises from such indoor contamination relative to dietary exposure. 

Additionally, there is the crucial consideration of the extent to which such external exposure translates into internal exposure or body burden. To date, there is only one paper that makes a definitive link between indoor contamination (specifically of dust) and body burden for PBDEs (Wu et ah, 2007). While there are few data relating to such bioavailability issues for indoor air and dust, the situation is not appreciably less certain than for dietary exposure. An important recent study (Huwe et al, 2008) has compared the bioavailability of PBDEs administered to rats in both indoor dust and in corn oil. While there was considerable congener-specific variation in uptake, there were no significant differences in uptake for a given congener regardless of whether it was administered in dust or corn oil. 

Given the likely vast reservoir of POPs associated with indoor environments (in air, dust, and in treated goods/materials), Harrad and Diamond (2006) proposed that this reservoir was exerting and would continue to exert, for the foreseeable future, a significant impact on outdoor contamination and thus human exposure. This concept is dealt with in detail in Chapter 8, but is mentioned here briefly to underline further the importance of indoor contamination. In short, several studies have shown marked urban pulses of both PCBs and PBDEs, whereby concentrations in both outdoor air and soil are correlated positively with the distance from the urban centres of Birmingham, UK, and Toronto, Canada (Harner et al, 2006 Harrad and Hunter, 2006 Jamshidi et al, 2007 Motelay-Massei et al., 2005). A further link between indoor and outdoor contamination was made by the correspondence between the chiral signatures of PCBs 95 and 149 in indoor and outdoor air, but not soil, in Birmingham (Jamshidi et al., 2007). 

This chapter has shown the importance of indoor contamination with POPs and demonstrated clearly that it is a fertile area of research. While good progress has been made with furthering our knowledge of many aspects, there are a number of areas that the author believes will form the focus of research efforts over the next few years. Specifically, these include studies to ... 

Evaluate the extent to which indoor contamination impacts on the outdoor environment. 

Aspergillus flavus and A. parasiticus produce the mycotoxin aflatoxin Bl. Aflatoxin B1 is a carcinogenic chemical that can cause liver cancer. Both ingestion and inhalation are proven exposure routes. Aflatoxin Bl has been found on contaminated grains, peanuts, and other foodstuffs. A. flavus and A. parasiticus are not commonly considered an indoor contaminant, unless the grains, peanuts, cereal-based animal food, or other foodstuffs are stored in an indoor environment. 

For a long time, remaining indoors was considered to afford protection from air pollution, and early studies of indoor air quality were generally concerned with examining the ratios of indoor to outdoor concentrations of various contaminants since it was felt that indoor contaminant levels were... 

Exposure to indoor contaminants in a workplace can be reduced by proper ventilation. Ventilation can be provided either by dilution ventilation or by a local exhaust system. In dilution ventilation, air is brought into the work area to dilute the contaminant sufficiently to minimize its concentration and subsequently reduce worker exposure. In a local exhaust system, the contaminant itself is removed from the source through hoods. Discuss why a local exhaust system is often preferred to a dilution ventilation system. 

Abstract Indoor contamination is one source of exposure to toxic pollutants and has been classified as a high environmental risk. Epidemiological research linked health effects including childhood leukemia and neuroblastoma to the indoor occurrence of pesticides. Pesticides in indoor environments contribute to human exposure via inhalation, non dietary ingestion and dermal contact. Sources for pesticides indoors are direct applications, pesticides used in varnishes, colors, adhesives, etc., or in finishing textiles, leather, carpets, etc., and pesticides brought in from outdoors. Results for pesticides in indoor environments from different countries and obtained under different conditions are compiled in this chapter. They are discussed by applying two approaches (1) the comparison with reference values... 

During the last 2 decades there has been increasing concern over the effects of indoor contamination on health. Changes in building design intended to improve energy efficiency have meant that modern homes are frequently more airtight than older structures [4]. 

A source often unknown for indoor contamination with pesticides is treated... 

Residues of pesticides from representative collectives concerning Germany and the USA are compiled in Tables 3 and 4. Ninety fifth percentiles represent a measure for the ubiquitous indoor contamination in these countries. 

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