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Determination of Organic Contaminants in Residential Indoor Air Using an Adsorption-thermal Desorption Technique
Abstract
This field study evaluated the ability of a multi-sorbent sampling tube/thermal desorption technique to identify and to provide quantitative data on volatile organic contaminants in indoor air. Air samples, from 12 Canadian homes, were collected on multilayer sorbent cartridges and analyzed using Adsorption/Thermal Desorption coupled with Gas Chromatography/Mass Spectrometry. The study included the identification and quantitation of 23 target compounds. Analysis of sorbent tubes fortified with these target compounds indicated that recoveries were greater than 70 percent and the precision was usually better than 15 percent. These organic compounds were found to be stable on the sorbent tubes for at least seven days. With some exceptions, the target compounds were usually detected at 1 to 10 micrograms/m3 in indoor air samples; other organics identified qualitatively were saturated hydrocarbons, unsaturated hydrocarbons, cyclic hydrocarbons, substituted aromatics, oxygenates, some halogenates and cyclic species such as camphenes/pinenes and carenes.
... La publication de Holcomb et Seabrook[14] nous donne une synthèse des différents résultats trouvés lors des différentes études. Pour les COV, nous avons choisi de prendre les résultats obtenus parChan et al. (1990) [147] pour notre travail, compte tenu qu'ils reflètent les tendances générales.L'étude en question a été réalisée au Canada à l'intérieur d'un bâtiment et à l'extérieur sur deux périodes données (novembreldécembre et févrierlmars). Les concentrations données sont des concentrations moyennes en pg/m3, elles sont résumées dans le tableau no 23.Nous avons retenu pour nos calculs ultérieurs la moyenne des concentrations intérieures et la moyenne des concentrations extérieures. ...
... La publication de Holcomb et Seabrook[14] nous donne une synthèse des différents résultats trouvés lors des différentes études. Pour les COV, nous avons choisi de prendre les résultats obtenus parChan et al. (1990) [147] pour notre travail, compte tenu qu'ils reflètent les tendances générales.L'étude en question a été réalisée au Canada à l'intérieur d'un bâtiment et à l'extérieur sur deux périodes données (novembreldécembre et févrierlmars). Les concentrations données sont des concentrations moyennes en pg/m3, elles sont résumées dans le tableau no 23.Nous avons retenu pour nos calculs ultérieurs la moyenne des concentrations intérieures et la moyenne des concentrations extérieures. ...
Nous passons la majorité de notre temps à l'intérieur de locaux. A partir de ce constat, l'auteur se propose d'évaluer et de comparer le risque sanitaire lié à l'inhalation chronique à l'intérieur et à l'extérieur de 8 composés organiques volatils (benzène, toluène, styrène, xylène(s), formaldéhyde, chloroforme, trichloroéthylène, tétrachloroéthylène) et du benzo(a)pyrène, polluants communs de l'intérieur de l'habitat. La démarche habituelle pour toute évaluation de risque sanitaire en 4 étapes est utilisée. En effet, après l'identification des dangers, l'auteur dresse la liste des effets sur la santé engendrés par l'inhalation des polluants étudiés. Puis, à partir d'une enquête Emploi du temps de l'INSEE et de données de la littérature sur les concentrations moyennes à l'intérieur et à l'extérieur des 9 polluants, il a été possible d'évaluer l'exposition aux polluants de 3 individus-types sur une vie entière et de procéder au calcul du risque sanitaire. L'auteur tiendra compte du caractère cancérigène ou non de la substance. Il en ressort que, pour les substances dites non cancérigènes, il ne semble pas exister de risque d'apparition d'effets pathologiques en rapport avec leur inhalation. En revanche, pour les substances considérées comme cancérigènes, le risque calculé est loin d'être négligeable. Globalement, le risque sanitaire lié à l'inhalation intérieure est nettement supérieur à celui lié à l'inhalation extérieure.
... The concentration of chloroform in the drawing room air was frequently as high as five parts per billion (ppb), although they had not identified the specific source. The Total Exposure Assessment Method (TEAM) research executed by the USEPA between 1979 and 1985 revealed that chloroform concentrations in personal air are five to twelve conditions greater than those in outdoor air [53]. In the past, they expected one zero. ...
Emerging contaminants are dispersed during environmental matrices and enter the environment through various anthropogenic causes. Even though there have been significant improvements in the detection and examination of suggested pollutants in recent years, various undiscovered contaminants that pose a threat to the environment must be found and measured in diverse environmental components. These contaminants may be dispersed and persistent in the air and ecological receptors even at low concentrations. There still needs to be more reliable information on their destiny and environmental behavior, as well as the dangers they pose to the ecosystem and human well-being. The environmental impact of several developing micropollutants still needs to be clarified since there is frequently insufficient data to assess their danger.
... It is known to be toxic to humans because its exposure can cause damage to the central nervous and reproductive systems (Sherrington and Routledge, 2001). Moreover, it is listed as a potential carcinogen and it is observed in outdoor and indoor air in the mid-pptC to ppbC range (Chan et al., 1990;Fraser et al., 1998;Rothweiler et al., 1992;Zielinska et al., 1996). ...
The formation of secondary organic aerosol (SOA) generated by irradiating styrene in the presence and/or absence of OH, NOx, H2O vapour and seed aerosol has been investigated for the first time. Experiments were conducted in a smog chamber at 298 K and atmospheric pressure. Styrene decay was measured by gas chromatography with a mass spectrometric detector (GC-MS), and the temporal evolution of the aerosol was monitored using a fast mobility particle sizer (FMPS). The SOA yield increases as the initial styrene concentration increases, leading to yields ranging from 1.8% to 3.5% for styrene photolysis, and from 2.4% to 5.0% for its photooxidation. In both cases, the organic aerosol formation can be expressed by a one-product gas/particle partitioning absorption model. The particle number concentration, mass and yield decrease in the presence of NOx and seed aerosol but increase at higher relative humidity (RH). The gas phase and SOA composition were analysed offline using a filter/denuder sampling system simultaneously collecting gas- and particle-phase products. Benzaldehyde was confirmed as the main gas-phase product of the reaction. However, although products in the particle phase were detected, they could not be identified. Moreover, the aqueous filter extracts were analysed using UV–Visible spectrophotometry to determine differences in the optical properties of SOA produced in the presence and absence of NOx. The results from this work may be used to discuss the implications of atmospheric SOA generation from styrene degradation.
... Les composés aromatiques de la famille du styrène ont été identifiés en tant que polluants toxiques et ont été mesurés aussi bien dans des atmosphères intérieures qu'extérieures (Harwell et al., 1992, Namiesnik et al., 1992. Leurs sources d'émissions, principalement anthropiques, sont diverses : solvants (Nelson et al., 1983), combustion (Spicer et al., 1992), industries, véhicules ou encore matériaux de constructions (Rothweiler et al., 1992, Chan et al., 1990. Ces sources d'émissions en font des composés dont l'exposition est aussi bien extérieure qu'intérieure, allant de quelques ppb (Grosjean et Fung, 1984) à quelques ppm. ...
The general context of this study is the on-line analysis of Secondary Organic Aerosol (SOA) chemical composition for a better understanding of its formation and aging. It consists in the development of a thermal desorption chemical ionization mass spectrometer: TDCIAMS. The instrument performances characterization and the study of the SOA formed from a-pinene ozonolysis in an Atmospheric Simulation Chamber (ASC) have shown that the TDCIAMS is well adapted to quantitative analysis of SOA generated in ASC. Concentration profiles of SOA components permit to obtain essential information about SOA formation mechanisms and aging. Moreover, the analysis of the SOA formed from the ozonolysis of two less studied anthropogenic compounds (2-methylstyrene and indene) has been realised and compared with those made by an off-line analysis method (SFE-GC-MS).
... The Shepherd, Corsi, and Kemp presence of organic precursors from clothes, free residual chlorine from commercial bleach, elevated wash water temperature, and low ammonia concentrations (e.g., less than 1 mg/L) should promote chloroform formation. A simplified reaction mechanism that illustrates such formation is: n Y X + n n i>OP -> n c CHCl 3 + n Rcl RCl (1) where X = free residual chlorine (HOC1, OC1-and Cl 2 ), OP = organic precursors, CHC1 3 = chloroform, RC1 = other chlorinated hydrocarbons, and ^ = moles of substance i. Other chlorinated hydrocarbons that form in the presence of chlorine have been described in detail elsewhere, 20 and will not be considered further in this paper. ...
A residential washing machine was studied in order to determine the extent of chloroform formation following the application of a laundry bleach containing sodium hypochlorite. A dynamic model was also developed to estimate chloroform formation, mass transfer, and gaseous emissions during a typical wash cycle. A series of 22 experiments was completed to determine model parameters, including chemical reaction and mass transfer rate coefficients, as well as headspace air exchange rates. Three additional experiments were completed to evaluate model performance. Experimental and model results suggest that washing machine environments are very conductive to chloroform formation, with chloroform levels frequently exceeding 1 mg/L in washwater. Chloroform stripping efficiencies were observed to be greater than those previously reported for ethanol, but less than those reported for radon. Mass emissions of chloroform to indoor air during a ten-minute wash cycle were predicted to be between 5.3 and 9.8 mg. On a unit activity basis, chloroform emissions associated with hypochlorite-containing bleach addition to washing machines far exceeded emissions from showers. Each source was estimated to emit similar quantities of chloroform on an annual basis. Finally, it was estimated that the use of hypochlorite-containing laundry bleaches may contribute a significant fraction of chloroform mass loadings to municipal wastewater.
... Data sets from the Southern California air quality study in ambient air (SCAQS) in 1987 (Lurmann and Main, 1992), Los Angeles during summer of 1997 (George et al., 1999), the EPA 29 City Average (Jeffries, 1995), Atlanta roadway in summer 1990 (Conner et al., 1995), and the BERLIOZ-1998 campaign in rural Germany (Konrad et al., 2000), revealed concentrations of internal alkenes of 0.006-3 ppb levels (Table 1). Finally, styrene is a hazardous air pollutant under the 1990 Clean Air Act, and it is observed in ambient and indoor air in the mid-pptC to ppbC range (Chan et al., 1990;Rothweiler et al., 1992;Zielinska et al., 1996;Fraser et al., 1998). ...
OH formation from the ozonolysis reactions of seven internal alkenes with 4–6 carbons, styrene, trans-β-methyl styrene, and α-methyl styrene was studied using complementary techniques. A small-ratio relative-rate technique in which small quantities of OH tracers are added to monitor OH formation yields provided the following results: trans-2-butene, 0.64±0.12; cis-2-butene, 0.33±0.05; trans-2-pentene, 0.46±0.08; cis-2-pentene, 0.29±0.06; trans-3-hexene, 0.53±0.08; cis-3-hexene, 0.36±0.07; and 2-methyl-2-butene, 0.98±0.24. For styrene, trans-β-methyl styrene, and α-methyl styrene, OH yields of 0.07±0.04, 0.22±0.09, and 0.23±0.12 were measured, respectively. A second method, which monitors product formation from the OH reaction with 2-butanol was used to derive OH formation yields from 2,3-dimethyl-2-butene, 2-methyl-2-butene and cis-2-pentene, and provided yields of 0.91±0.14, 0.80±0.12, and 0.27±0.07, respectively. The results are briefly discussed in terms of the relationship between structures of these alkenes and OH formation.
... This compound did not arise from the air fresheners tested. It is widely used as an insecticide and a fumigant for control of mildew and moulds and for moth control [39], and is known to be one of the ubiquitous contaminants of residential air [32,[40][41][42][43][44][45][46]. The main source of p-dichlorobenzene in the cabins was presumed to be the seats contaminated by the compound from the occupant's clothes that had been stored with repellents containing p-dichlorobenzene. ...
The types and concentrations of organic compounds in the interior air of 101 different types of Japanese domestically produced private-use cars were examined. All the vehicles had been registered in the summer season as new cars and were less than 3 years old. The airborne compounds in the cabins were collected for 24h under static condition with the engine stopped and the windows, doors and vents closed. A total of 275 organic compounds, including many aliphatic hydrocarbons and aromatic hydrocarbons, were identified, and 242 of them could be quantitated for each cabin. The sum of the concentrations of 241 compounds excluding formaldehyde was approximately 600 g·m-3 as a median, ranging from 136 to 3968 g·m-3 for the tested cars. The findings demonstrated that the air in the cabin of these cars was contaminated by high concentrations of a large variety of organic compound diffusing from the interior materials.
... Airborne limonene may be collected by charcoal tube sampling followed by desorption with carbon disulfide (Searle, 1989) or alternatively on Tenax (Janson & Kristensson, 1991) or on multisorbent sampling tubes (Chan et al., 1990) followed by thermal desorption. Limonene is usually analysed by gas chromatography with flame ionization detection or mass spectrometry. ...
... Presented as geometric mean (75%1*25%1e) of data assuming lognormality, from Seifert and Abraham (1982), Le Bret et al. (1984), De Bortoli et al. (1984, Monteith et al. (1984), Gammage et al. (1986Gammage et al. ( , 1988, Wallace et al. (1986Wallace et al. ( , 1990, Sheldon et al. (1988), Hodgson and Girman (1989), Cohen et al. (1989), Chan et al. (1990), Baldwin and Farant (1990), Rothweiler et al. (1990). ...
A review is presented of investigations of volatile organic compound (VOC) concentrations in indoor air of buildings of different classifications (dwellings, offices, schools, hospitals) and categories (established, new and complaint buildings). Measured concentrations obtained from the published literature and from research in progress overseas were pooled so that VOC concentration profiles could be derived for each building classification/category. Mean concentrations of individual compounds in established buildings were found to be generally below 50 μg/m3, with most below 5 μg/m3. Concentrations in new buildings were much greater, often by an order of magnitude or more, and appeared to arise from construction materials and building contents. The nature of these sources and approaches to reduce indoor air concentrations by limiting source VOC emissions is discussed. Total VOC (TVOC) concentrations were substantially higher than concentrations of any individual VOCs in all situations, reflecting the large number of compounds present, but interpretation of such measurements was limited by the lack of a common definition for TVOC relevant to occupant exposure.
... 15) Brown and Purnell, 1979. 16) Chan et al., 1990. 17) Cao and Hewin., 1991. ...
... In adition to that, in American office buildings acetone and 2-buthoxyethanol also 317 have been detected in relevant abundance (Griman et al., 1999). These above 318 mentioned compounds have been detected in the studied dwelling (Table 2;Table 3Hartwell et al., 1984; Gupta 333 et al., 1984; Lerbet et al., 1986; Pellizzari et al., 1986; Krause et al., 1987; Wallace et 334 al., 1987; Montgomery and Kalman, 1989; Chan et al., 1990; Proctor et al., 335 1991;Holcomb and Seabrook, 1995; Koistainen, 1995; Baek et al., 1995; Lee et al., 336 2002; Guo et al., 2004). Hence, the general distribution of VOC in indoor air is the 337 standard for an established dwelling, however, several compounds are detected in 338 higher concentrations than the expected (e.g. ...
A methodology for identifying volatile organic compounds (VOCs) and determining air quality of indoor air has been developed. The air samples are collected using pump samplers by the inhabitants when they perceive odorous and/or discomfort episodes. Glass multi-sorbent tubes are connected to the pump samplers for the retention of VOC. The analysis is performed by automatic thermal desorption (ATD) coupled with gas chromatography-mass spectrometry (GC/MS). This methodology can be applied in cases of sick building syndrome (SBS) evaluation, in which building occupants experience a series of varied symptoms that appear to be linked to time spent in the building. Chemical pollutants concentrations (e.g., VOC) have been described to contribute to SBS. To exemplify the methodology, a qualitative determination and an evaluation of existing VOC were performed in a dwelling where the occupants experienced the SBS symptoms. Higher total VOC (TVOC) levels were detected during episodes in indoor air (1.33 +/- 1.53 mg/m3) compared to outdoor air (0.71 +/- 0.46 mg/m3). The concentrations of individual VOCs, such as ethanol, acetone, isopropanol, 1-butanol, acetic acid, acetonitrile and 1-methoxy-2-propanol, were also higher than the expected for a standard dwelling. The external source of VOC was found to be an undeclared activity of storage and manipulation of solvents located at the bottom of a contiguous building.
Description
The first publication of its kind to feature comprehensive information on the regulation, measurement, and control and remediation of VOCs in the soil, groundwater and air. 21 peer-reviewed papers from an international array of scientific, legal and environmental experts in the field.
Key topics addressed include: A multimedia perspective on VOCs in the environment • Challenges involved with the regulation and assessment of VOCs • The impact of VOCS on air quality • Methods to ascertain the environmental fate of VOCs • Environmental measurement and monitoring techniques Innovative approaches to control and remediate VOCs.
Invaluable resource for the complete spectrum of environmental professionals: engineers, chemists, scientists, regulators and remediation specialists and program managers, as well as federal and state agency environmental personnel and university libraries.
Several billion pounds of ketones are produced annually for industrial use in the United States and worldwide. Those with the highest production volumes include acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, 4‐hydroxy‐4‐methyl‐2‐pentanone, isophorone, mesityl oxide, and acetophenone. Common methods used to manufacture ketones include aliphatic hydrocarbon oxidation, alcohol dehydration with subsequent oxidation, dehydrogenation of phenol, alkyl aromatic hydrocarbon oxidation, and condensation reactions. Ketones are commonly used in industry as solvents, extractants, chemical intermediates, and, to a lesser extent, flavor and fragrance ingredients. Although a common effect of excessive ketone exposure is CNS depression some ketones have pulmonary effects that are well below levels that cause acute CNS effects. For example, ketones such as diacetyl and chemically similar chemicals used for flavoring foods, coffee, and e‐cigarettes provide opportunities for widespread exposure and very debilitating pulmonary disease including bronchiolitis obliterans.
In this study, a large-scale in-cabin benzene series hazard detection is firstly performed on 20 electric buses by a full-scale climate chamber. The sources of BTEX are analyzed deeply by parts detection, and a series of effective measures are performed to reduce BTEX. Firstly, the in-cabin BTEX pollution with considerations of a series of parameters, such as interior configuration, environment temperature, vehicle age, and ventilation mode, is analyzed. The result shows that: 1) The VOCs concentrations decrease with vehicle age, higher configuration level and better ventilation system (particularly, fresh wind mode reduce VOCs fastly), while increases with environment temperature; 2) BTEX in bus cabins occupy approximatively 70.1% of TVOC, thus the BTEX overproof is the main culprit which causes VOCs to exceed standard. Then, measurements on components/materials VOCs releases were performed in a small climate chamber to discriminate key species and their sources. Xylene released from glues materials is found as a key species that causes BTEX/VOC to exceed limitation. Lastly, some measures, such as optimizations of materials selection and manufacturing crafts, are adopted to improve in-cabin pollution, and positive effects are obtained. For example, ethylbenzene and xylene released from HL 125 (a polyurethane adhesive) decrease by 2456% and 1930% respectively after improvement. And in-cabin xylene and TVOC decrease by 2274% and 222%, respectively, and all of them are lower than limitation value.
The concentrations of eight volatile organic chlorinated chmicals in indoor air, outdoor air and personal exposure concentrations in five married couples living in Osaka were determined in October and February, each twice (1995 and 1996), in order to know the pollution levels of the chemicals in residential air and to estimate the absorption amounts of them in personal exposure lebvels.
The chmicals in atmosphere were collected by passive gas sampling tubes containing charcoal, and were determined by using gas chromatograph with electron capture detector. The geometric mean of. indoor concentration of p-dichlorobenzene (3.1 ppb, v/v) was highest, followed by those of 1, 1, 1-trichloroethane (0.52 ppb), trichloroethylene (0.47 ppb), chloroform (0.39 ppb), tetrachloroethylene (0.28 ppb), carbon tetrachloride (0.093 ppb), bromodichloromethane (0.052 ppb) and chlorodibromomethane (0.024 ppb). As indoor concentrations of p-dichlorobenzene and trihalomethanes were higher than outdoor concentrations of them in all houses, major sources of these chemicals were considered to be present in indoor. Further, the sources of the trihalomethanes were presumed to be same on the basis of the results of the correlation analysis among the concentrations of eight chemicals. The personal exposure concentrations of p-dichlorobenzene (1.5-21.2 ppb) were highest of those of the chemicals in husbands and wives in all homes.
The absorption amounts of each chemical in personal exposure levels were estimated from the results of the previous pharmacokinetic studies of the chemicals in rats. p-Dichlorobenzene (2456nmol/day/60 kg of human body weight) was absorbed most abundantly amoung the volatile organic clorinated chemicals, comprising about 70% of the total absorption amounts of eight chemicals. The amounts of trichloroethylene (84 nmol) and chloroform (224nmol) were much next to that of p-dichlorobenzene, but the absorption amounts of the other five chemicals were much less than those of p-dichlorobenzene, trichloroethylene and chloroform. p-Dichlorobenzene, which was possibly carcinogenic to humans and was absorbed abundantly, was considered to be one of thee most noteworthy chemicals as indoor contaminant inhaled chronically.
As a promising sample preparation technique, purge and trap(P&T) followed by thermal desorption-gas chromatography(TD-GC) has been widely used in analytical chemistry in recent years. In this paper, a laboratory evaluation of adsorbents with a TD-GC was developed - several different adsorbents or adsorbent combinations were evaluated for their ability to retain and to be thermally desorbed regard to volatile organic compounds. The amounts of analystes recovered from the adsorbents were quantitated using a GC equipped with a flame ionization detector. The results of these evaluations indicate that multisorbents, such as Tenax GC: actived carbon=2:1 (V/V), perform well for collecting a diverse range of volatile organic compounds (VOCS), Multi-adsorbents have potential widespread application in the environmental field for purge and trap and air sampling of trace VOCS.
Xylenes are included on the List of Priority Substances to be assessed under the Canadian Environmental Protection Act. On the basis of available data, they have been classified as “unlikely to be carcinogenic to humans”. Total average daily intakes of xylenes for the general population in Canada estimated based on data on concentrations in ambient and indoor air, drinking water and at self‐serve gasoline stations are less (by 16 to 40 times) than the tolerable daily intake derived on the basis of studies in laboratory species.
Toluene is included on the List of Priority Substances to be assessed under the Canadian Environmental Protection Act. Based on available data, it was concluded that toluene is “unlikely to be carcinogenic to humans”. The estimated average daily intakes of toluene for various age groups in the general population are 68 to 131 times less than the tolerable daily intake derived on the basis of data from bioassays in animal species and that calculated from clinical studies in human volunteers.
The gas-phase chemistry of the nitrogen-containing organic compounds indole, quinoline and isoquinoline, which are present in environmental tobacco smoke, has been investigated. No photolysis of these nitrogen heterocycles was observed under indoor “white” fluorescent lighting conditions. Rate constants for the gas-phase reactions of these compounds with OH radicals, NO3 radicals, NO2, and O3 were measured, and the rate constants obtained (in cm3 molecule−1s−1 units) were: for reaction with the OH radical: indole, (1.54 ± 0.35) × 10−10; quinoline, (1.16 ± 0.55) × 10−11; isoquinoline, (8.5 ± 3.6) × 10−12; for reaction with the NO3 radical: indole, (1.3 ± 0.5) × 10−10; for reaction with NO2: indole,< 2 × 10−19; quinoline, < 1.6 × 10−20; isoquinoline,< 1.1 × 10 and for reaction with O3: indole, (4.9 ± 1.8) × 10−17; quinoline, < 1.0 × 10−19; and isoquinoline, < 1.1 × 10−19. Evidence was obtained that quinoline reacts with gas-phase nitric acid and this is also expected to be the case for isoquinoline. These data indicate that in indoor environments, quinoline and isoquinoline will be largely removed by air exchange unless gas-phase nitric acid is present, while indole will be removed by chemical reaction if NO3 radicals are present at part-per-trillion levels. Products of the O3 and OH radical reactions with indole have been studied and the possible O3 reaction mechanism is discussed.
Recently published studies where individual volatile organic compounds (VOCs) have been identified and quantified have been reviewed. Mean con centrations of the compounds have been calculated for public places, homes, and transportation environments. Where the data were available to differen tiate between smoking and non-smoking areas these have been summarised. Studies which have attempted to assess health impacts such as odour and irri tation in conjunction with VOCs appear to be using unrealistic mixtures and concentrations of VOCs compared to those found in real life situations. Future research employing more realistic concentrations of VOCs will aid in under standing the true effect VOCs may have on indoor air quality and the persons exposed in that environment. Research using the American Society of Testing and Materials (ASTM) animal bioassay E981-84 may provide a reasonable method for establishment of human exposure guidelines. Concentrations found to cause irritation in humans are higher than typical indoor levels found in this review. Irritation is unlikely to occur at the mean levels reported herein. In general, where ventilation rates meet or exceed the requirements of ASHRAE Standard 62-1989, Ventilation for Acceptable Indoor Air Quality, TVOC levels are low, usually less than 1 mg/m3 and concentrations of individ ual VOCs are well below (less than 1 %) any recognised occupational exposure standard.
Styrene has been assessed as a Priority Substance under the Canadian Environmental Protection Act. Based on available data, styrene has been classified as “possibly carcinogenic to humans”, and tolerable daily intakes/concentrations developed based on relevant studies in animals. The estimated average total daily intake of styrene by the Canadian general population is more than 50 times less than the TDI/TDC for neurotoxic effects following inhalation, or for foetotoxic effects following long‐term exposure to styrene by the oral route.
More than 90% of the 75,000 chemicals listed in EPA's Toxic Substances Control Act Chemical Substance Inventory and 88% of the 189 Hazardous Air Pollutants (HAPs) named in the Clean Air Act Amendments of 1990 are organic. Methods for collecting organic chemicals from the air for analysis are often complicated and depend on the volatility of the compounds, as well as other chemical and physical properties. The various methods of sampling airborne organics are reviewed and discussed here and 275 literature citations are given. Special sampling difficulties associated with chemical behavior in the atmosphere, such as reactivity and phase distribution, are discussed. The pros and cons of sampling devices, sorbents, and other sampling parameters are presented in the context of chemical type, with special application to the Clean Air Act HAPs. The elements of good quality assurance practice in organic chemical air sampling are also discussed.
The products of the gas-phase reactions of styrene and 2-vinylpyridine with O3, OH radicals, and NO3 radicals have been studied at room temperature and atmospheric pressure of air. The reaction kinetics were also measured for those reactions not previously examined. The major products of the ozone reaction with styrene were formaldehyde and benzaldehyde, each with yields of approximately 40%. The OH radical reaction with styrene also formed benzaldehyde and formaldehyde with yields of 63 +/- 6% and 72 +/- 7%, respectively. The reaction of styrene with the NO3 radical formed equal, minor yields (ca. 11%) of HCHO and C6H5CHO, with the remaining unidentified products consisting of transient and stable species which contain ONO2, OONO2, and C=O groups. The 2-vinylpyridine reaction with ozone produces 2-pyridinecarboxaldehyde and formaldehyde, with respective yields of 80 +/- 9% and 34 +/- 5%. 2-Pyridinecarboxaldehyde was also the major product of the OH radical reaction with 2-vinylpyridine, with a yield of 78 +/- 14%.
Some data on a newly developed filter/sorbent indoor air SVOC sampling device for thermal desorption analyiss are described. Thermal desorption of SVOCs spiked on Tenax had reponse factors identical to on-column injection except for highly polar compounds like fatty acids. SVOCs spiked on quartz fiber filters had response factors that on an average were 80% of the on-column response factors (66% for oxygen containing compounds and 87% for non-oxygen compounds) Low nanogram on-tube amounts of SVOCs were found generally to have lower recoveries than larger amounts from both Tenax and quart fiber filters. This appeared to be explained in part by a relatively larger “memory” effect and lower desorption efficiency. In addition, it was indicated that the “memory” effect was an important source of background contaminations that might impair analysis of low nanogram on-tube amounts of some SVOCs. Polar SVOCs. Polar SVOCs in the gas phase appear to adsorbto the quartz fiber filters. This functions as a precleaning of the sample and thus minimizes the problem with coeluting peaks. The relative standard from nine duplicate samples appeared to be sufficiently low to distinguish a day variation.
A ketone is an organic compound containing a carbonyl group (CO) attached to two carbon atoms and can be represented by the general formula
Several billion pounds of ketones are produced annually for industrial use in the United States. Those with the highest production volumes include acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, 4‐hydroxy‐4‐methyl‐2‐pentanone, isophorone, mesityl oxide, and acetophenone. Common methods used to manufacture ketones include aliphatic hydrocarbon oxidation, alcohol dehydration with subsequent oxidation, dehydrogenation of phenol, alkyl aromatic hydrocarbon oxidation, and condensation reactions.
Ketones are used because of their ease of production, low manufacturing cost, excellent solvent properties, and desirable physical properties such as low viscosity, moderate vapor pressure, low to moderate boiling points, high evaporation rates, and a wide range of miscibility with other liquids. The low‐molecular‐weight aliphatic ketones are miscible with water and organic solvents, whereas the high‐molecular‐weight aliphatic and aromatic ketones are generally immiscible with water. Most ketones are chemically stable. The exceptions are mesityl oxide, which can form peroxides, and methyl isopropenyl ketone, which polymerizes. Most ketones are generally of low flammability.
Ketones are commonly used in industry as solvents, extractants, chemical intermediates, and to a lesser extent, flavor and fragrance ingredients. Ketones have also been reported in the ambient air, in wastewater treatment plants, and in oil field brine discharges.
The photocatalyzed oxidation of gas-phase contaminants in air is being more and more explored regarding the possible applications: decontamination, deodorization and purification of enclosed atmospheres. In the present work, the photocatalytic degradation of a typical malodorous pollutant of indoor air: methyl ethyl ketone (MEK) has been investigated by using an annular photoreactor. The annular photoreactor was modelled by a cascade of heighten elementary continuously stirred tank reactors. The influence of several kinetic parameters such as pollutant concentration, oxygen content, humidity content and incident light irradiance has been studied. The Langmuir–Hinshelwood model has been verified for MEK. The by-products of MEK photocatalytic degradation have been identified by GC/MS and acetaldehyde was found to be the main gaseous intermediate. Acetaldehyde thus has been taken into account in the general Langmuir–Hinshelwood model to evaluate the possible competition of adsorption between acetaldehyde and MEK. A mechanistic pathway is then proposed for the photocatalytic degradation of MEK.
A principal aspect of the 1993 Lower Rio Grande Valley Environmental Scoping Study was the analysis and interpretation of residential air, household dust, and soil pollutant concentration data for exposure assessments. Measurements included respirable particulate matter (PM2.5), volatile organic compounds (VOCs), pesticides, and polycyclic aromatic hydrocarbons (PAHs) in indoor and outdoor air. Household dust, road dust, and yard soil were analyzed for elements, pesticides, and PAHs. Nine residences were monitored for three weeks in the spring of 1993. Additional monitoring was conducted at six of the nine residences for ten days the following summer. Generally good agreement was found between outdoor residential air and same-species measurements collected concurrently at a non-residential central site in Brownsville, TX (Ellenson et al. 1997) for fine particulate matter, elements, and VOCs indicating the dominance of regional influences. PM2.5 mass and element concentrations in residential indoor and outdoor air were generally higher in the summer than in the spring. Indoor air concentrations of many species were higher than outdoor air concentrations and were attributed to household activities, ventilation of residences, and track-in of dislodged soils. Evidence of agricultural activities was noted in the occurrence of crop-related pesticides (e.g., malathion and chlorpyrifos) in indoor and outdoor air. Concentrations of common household pesticides (e.g., chlordane, chlorpyrifos, diazinon, heptachlor, and propoxur) were generally higher indoors than outdoors and were also present in house dust. Seasonal comparisons of pesticides and PAHs were also presented using matched residences in spring and summer; VOCs also may have indicated seasonal effects. VOCs (notably propane and butane isomers) and PAHs were higher indoors, presumably due to cooking-related activities.
Analyses of indoor air samples of semivolatile organic compounds (SVOCs) from five offices in two office buildings, a school classroom, and a room in a day-care center were generally strongly influenced by artifact formation. In the laboratory, the major artifacts could be produced by sampling mixtures of O3, NO2, and limonene in air on the sorbent, Tenax TA. Several SVOCs from O3 degradation of Tenax TA were detected, but only few were identified. The NO2 degradation of Tenax TA analyzed by thermal desorption and gas chromatography (TD-GC) almost exclusively formed 2,6-diphenyl-p-benzoquinone (DPQ) and 2,6-diphenyl-p-hydroquinone (DPHQ). The NO2/Tenax TA reaction could be calibrated, thus the NO2 concentration could be determined simultaneously with a SVOC measurement. However, the results indicated that DPQ may be reduced to DPHQ during TD-GC analysis by oxidation of other compounds adsorbed to Tenax TA. Sampling an air mixture of O3 in excess of limonene on Tenax TA followed by TD-GC analysis exclusively produced DPHQ. O3 alone produced neither DPQ nor DPHQ. It was found that reactive species (possibly Criegee biradicals and/or other organic radicals) from the O3/limonene :reaction were responsible for the production of DPHQ from Tenax TA. The results indicated that Tenax TA can be used as a trapping agent for some radicals by analysis of the DPQ/DPHQ formation. The present data were not sufficient to obtain evidence for degradation of Tenax TA by other radicals than NO and NO2 in indoor SVOC samples. However, the DPQ/DPHQ ratio indicated that DPHQ has been formed from DPQ by oxidation of other adsorbed compounds in some of the samples.
A canister-based sampling technique was combined with solid adsorbents to develop a method for the determination of 52 volatile organic hydrocarbons (VOCs), including alkanes, alkenes, aromatics and terpenes, in ambient air at pptv levels of concentration. The volatility of components ranged from propane to that of 1,2,4-trimethylbenzene. The samples were collected into stainless steel canisters. A 200-ml sample volume was drawn through a multilayer adsorbent bed. Three different adsorbents, 300 mg of Carbosieve S-III 60/80, 300 mg of Carbotrap 20/40 and 300 mg of Carbotrap C 20/40 were used for collecting large variety of hydrocarbons (C3–C10). Qualitative analysis was carried out by combining thermal desorption and cryogenic enrichment with high resolution gas chromatography and mass spectrometry. The technique was suitable for determination of low pptv-concentrations of VOCs. A detailed description of working procedures and methods is given including blanks, calibrations, limit of quantification and reproducibility of measurements. Ambient atmospheric sampling was conducted in Berlin in July, 1998. n-Hexane, benzene, toluene and m-, p-xylene presented in the air at the highest concentration at ppbv level, the concentration of the other compounds were in the order of 10–100 pptv level. Precision of parallel measurements was calculated. As expected, the precision was deteriorated with decreasing concentration. At concentrations >100 pptv, most duplicates differed by ±10–30%, below this value they were larger.
Forty-nine nonsmoking married women participated in a home personal exposure study for 28 volatile organic compounds (VOCs) and total volatile organic compounds (TVOCs). The women were selected and classified according to 18 socioeconomic categories based on age (18–34 y, 35–49 y, 50–64 y), family income (<25K, 25K-40K), and husband's smoking status. Of the 29 analytes, 21 demonstrated no statistically significant difference in concentration between nonsmoking and smoking homes. One VOC, trichloroethylene, was elevated in the nonsmoking homes and seven VOCs, benzene, styrene, pyridine, 2-picoline, 3-picoline, 3-ethylpyridine, and 3-ethenylpyridine were elevated in the smoking homes. A correlation matrix and a factor analysis indicate that benzene and styrene were not significantly correlated or associated with 3-ethyenylpyridine, a proposed vapor phase environmental tobacco smoke (ETS) marker. All of the nitrogenous bases were significantly correlated with 3-ethenylpyridine. Benzene, styrene, and TVOC were not significantly correlated with the number of cigarettes smoked; however, 3-ethenylpyridine was significantly correlated with the number of cigarettes smoked. A Pearson correlation analysis indicated that gas heat and smoking husband were significantly correlated with elevated benzene concentrations, but a multiple regression model for benzene accounted for less than 30% of the total variance. ETS variables accounted for only 8% of the total variance. In the smoking homes, an apportionment technique was evaluated for selected VOCs in order to determine the median percentage of each analyte attributable to ETS. The results, with percentages attributable to ETS were TVOC (5.5%), benzene (13.2%), styrene (12.6%), pyridine (40.7%), 2-picoline (67.1%), 3-picoline (90.1%), 4-picoline (37.2%), and 3-ethylpyridine (62.0%). Indoor air sources other than ETS were also identified for limonene, tetrachlorethylene, 1,4-dichlorobenzene, and alkylbenzenes.
Environmental tobacco smoke (ETS) is often cited as a key factor in indoor air quality (IAQ) and public health. However, there are few studies which attempt to actually calculate the impact ETS has on IAQ or the doses of ETS one may receive from possible exposure in a variety of different settings. This paper reviews the data on indoor air published since 1980 and estimates the portion of various constituents which are produced by ETS. It can be observed that, in most instances, ETS has only a minor impact on IAQ. Retained doses of ETS particles are calculated for various exposure scenarios using respirable particle concentrations associated with ETS, time activity patterns, respiration rates and retention rates. Total doses range from 3–40 mg/y. This dose level does not seem to support the summary relative risk of 1.35 that has been claimed from metaanalyses of epidemiologic studies of spousal smoke exposure and lung cancer.
One hundred-four self-reported nonsmoking married women participated in a home and workplace personal environmental tobacco smoke (ETS) exposure study for 33 volatile organic compounds (VOCs), total volatile organic compounds (TVOCs), respirable suspended particulate matter (RSP), and ETS-RSP. The women were selected and classified according to socioeconomic categories based on age (25–39 y and 40+ y), total annual household income (<40K), and reported ETS exposure status at home and at work (SH = smoking home, NSH = nonsmoking home, SW = smoking work, and NSW = nonsmoking work). Saliva samples were collected at the start and at the end of the study for cotinine determinations. Five participants (4.8% of the total), married to smokers and working in smoking workplaces, were excluded because they had average salivary cotinine concentrations greater than 10 ng/mL indicating that they were likely smokers. The background correction factor for cotinine (SH/NSH) or Z, indicated that total exposure was 4.8 times greater for those living with a smoker versus those not living with a smoker. Apportionment of TVOCs indicated that 3.4% of the TVOCs in the smoking homes and 0.8% of the TVOCs in the smoking workplaces were attributable to ETS. Apportionment of benzene and styrene indicated that 11.4% and 13.4%, respectively, were attributable to ETS in smoking homes; 11.5% and 6.2%, respectively, were attributable to ETS in smoking workplaces. RSP apportionment based on solanesol particulate matter (Sol-PM) indicated that 28.7% of the RSP in smoking homes and 22.7% of the RSP in smoking workplaces were attributable to ETS. RSP apportionment based on scopoletin particulate matter (Sco-PM) indicated that 12.9% of the RSP in smoking homes and 9.6% of the RSP in smoking workplaces were attributable to ETS. Median daily and weekly exposures to VOCs, TVOCs, and RSP were calculated from the concentrations determined and tended to follow the trend: SH > NSH > SW > NSW. The home/work exposure differential (SH/SW) indicated that ETS exposure was higher for living with a smoker than for working with a smoker by a factor of 3.7 for RSP and ETS-RSP and 2.4 for VOCs and TVOCs.
Volatile organic compounds are monitored by sampling of air to adsorbents. The adsorbed compounds are then extracted using solvents. Some solvents are flammable and/or toxic. In addition, some solvents may contain contaminants which will interfere with analysis. Furthermore, the sensitivity of analysis could be lowered by a factor of thousand because the analysis uses only a small aliquot of extracted solution. Thermal desorption method is free from these pitfalls. Thermal desorption gas chromatographic method is applied to the sampling and analysis of vinyl chloride in workplace air. The method is safe, fast, convenient and reliable.
Eight adsorbents were evaluated for sampling and quantitative analysis of microbially produced volatiles using thermal desorption-gas chromatography. The adsorbents studied were Tenax TA, Tenax GR, Chromosorb 102, Carbotrap C, Carbopack B, Anasorb 727, Anasorb 747 and Porasil C/n-octane (Durapak). The study was performed using a test atmosphere consisting of ten compounds differing in polarity and volatility: 2-propanol, dimethyl disulfide, toluene, furfural, 1-octen-3-ol, 3-octanone, 3-octanol, 2-isopropyl-3-methoxypyrazine, 2-methylisoborneol and geosmin. The adsorbents were tested under conditions found in “sick buildings”—low μg/m3 levels and varying humidity. Tenax TA proved to have the best properties considering the amount obtained, breakthrough and standard deviation during sampling/analysis.
Over 200 volatile organic compounds (VOCs) were identified by thermal desorption/gas chromatography/mass spectrometry in the indoor air of 26 houses. The most common VOCs were alkylbenzenes, alkanes, terpenes, aliphatic aldehydes, and some chlorinated aliphatic hydrocarbons. Forty eight compounds were selected for quantitative analysis on the basis of their prevalence, toxicity, carcinogenicity and mutagenicity. The selected compounds were quantified in 50 normal houses and 38 sick houses, in which people complained about the odor or they had symptoms, which resembled the Sick Building Syndrome. The concentrations of the VOCs exceeded normal level more often in the sick than in the normal houses. Aromatic hydrocarbons, terpenes, some alkylcyclohexanes, 1,1,1-trichloroethane, and tetrachloroetliene occurred most often with increased concentrations in the sick houses.
Air samples from 19 Kuwaiti residences were collected on tenax-TA sorbent cartridges and analyzed using adsorption/thermal desorption coupled with flame ionization detector/gas chromatography. The study included the identification of around 47 target compounds using the above technique. With the exception of Freons, the target compounds were usually detected at 100 to 5000 μ/m3 in indoor and outdoor air samples. Organics identified were aromatics, and aromatic and aliphatic halogenated hydrocarbons. The objective of this study was to identify and measure the Volatile Organic Compounds as well as to identify the sources wherever possible. Information regarding the homes, residents in the respective homes, and activities during the sampling period were gathered using a questionnaire.
The volatile organic compounds Benzene, Toluene, Ethylbenzene and Xylene (BTEX) are commonly found in petroleum derivatives and, at relatively high levels, can be associated with human health risks. Due to industrial activities, accidental petroleum spills are the main route of soil and groundwater contamination. The aim of the present study was to evaluate the indoor health risks due to tap water consumption contaminated by BTEX.
BTEX indoor exposure can occur through three principal pathways: inhalation, ingestion and dermal absorption. A multiphase and multicomponent model was used to simulate BTEX transport in groundwater. For evaluation of human risks due to the use of contaminated tap water, a mathematical model was elaborated.
BTEX concentrations in a drinking well were obtained as a function over time. These concentrations were used to obtain the exposure due to the use of water from the contaminated drinking well. In addition to showing the highest concentration in water, benzene was the compound that remained for a longer period before being completely degraded. For all the evaluated BTEX, oral ingestion was also the main pathway of exposure for adults, whereas the contribution of inhalation and oral exposition in children were seen to be of the same magnitude. The sensitivity analysis of BTEX total dose for adults showed that direct ingestion was the most significant factor, followed by shower time, volume of the shower room, inhalation rate, and shower flow rate. For children, the most significant variable was also direct ingestion, followed by shower time, volume of the shower room, and body weight.
In the current design situation, there would not be any health risks by the use of BTEX-contaminated water to the general population living in the neighborhood of the petroleum spill. Therefore, no remediation measures in the area of the spill would be necessary.
The present results indicate that the design of a good scenario can perform an accuracy risk assessment. This model can serve as a useful tool for predicting indoor exposure to substances for which no direct data are available, reducing monitoring efforts and observing how different processes affect outcomes.
These preliminary data allow the establishment of a basis for further investigations focusing on efficiently recovering petroleum from contaminated sites.
Fire-damaged houses are often refurbished for further use. In some cases occupants complain about odours from the fire in the refurbished houses. Experimental box fires and a field study of refurbished houses were un dertaken to investigate the problem. Concentrations of combustion products from fires in the experimental box were measured for up to 30 days afterwards and the decay of concentrations of the combustion products was calculated. The decay was faster in humid conditions than in dry conditions. There was a cor relation between the boiling point of compounds and the decay constant. Some compounds remained in higher-than-normal concentrations for several hun dred or several thousand days. Field studies of refurbished houses showed re sults consistent with the experimental study.
Thesis (Ph. D.)--Technical University of Denmark, 1998. "August 1998." Includes bibliographical references (p. 191-205).
Styrene is an extremely important commodity chemical used extensively in the manufacture of numerous polymers and copolymers, including polystyrene, acrylonitrile-butadiene-styrene (ABS), styrene-acrylonitrile (SAN), styrene-butadiene latex, and styrene-butadiene rubber. Styrene is a component of cigarette smoke and automobile exhaust, and it may occur naturally at low levels in various types of foods. The highest potential human exposures to styrene occur in occupational settings, particularly those involving the production of large glass-reinforced polyester products such as boats, which require manual lay-up and spray-up operations. Substantially lower occupational exposures occur in styrene monomer and polymer production facilities. The general public is exposed to very low concentrations of styrene in ambient air, indoor air, food, and drinking water.
A method was developed to determine aldehydes, ketones, esters, and ethers in air which is simple, efficient, and sensitive. Analytes are trapped on a glass cartridge filled with 4 in of Porapak N followed by 1 in of charcoal. These are eluted with 1 ml of methanol, and the eluate is injected onto a gas chromatograph equipped with a photoionization detector (PID). Quantitation is performed by measuring the peak height or area of each analyte of interest and comparing it with a standard in methanol. These cartridges can be reused a number of times after reconditioning. This method is efficient since it lends itself to the use of an autosampler, which can inject large numbers of samples onto the gas chromatograph while it is unattended.The method detection limit was from 0.6 to 16.5 &mgr;g/m3, which is comparable to other methods, and recoveries ranged from 83 to 120%. The sensitivity from highest to lowest, with respect to class of compound, was determined to be aldehydes, ketones, esters, and ethers. Up to 150 L of air can be passed onto the cartridge without any expected breakthrough of analytes, as opposed to only 10 to 30 L with 1 in of charcoal alone, which is normally the adsorbent of choice.
Xylenes, or dimethylbenzenes, are among the highest-volume chemicals in production. Common uses are for gasoline blending, as a solvent or component in a wide variety of products from paints to printing ink, and in the production of phthalates and polyester. They are often encountered as a mixture of the three dimethyl isomers, together with ethylbenzene. As part of its mandate, the Agency for Toxic Substances and Disease Registry (ATSDR) prepares toxicological profiles on hazardous chemicals found at Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) National Priorities List (NPL) sites that are of greatest concern for public health purposes. These profiles comprehensively summarize toxicological and environmental information. This article constitutes the release of the bulk of this profile (ATSDR, 1995) into the mainstream scientific literature. An extensive listing of known human and animal health effects, organized by route, duration, and end point, is presented. Toxicological information on toxicokinetics, biomarkers, interactions, sensitive subpopulations, reducing toxicity after exposure, and relevance to public health is also included. Environmental information encompasses physical properties, production and use, environmental fate, levels seen in the environment, analytical methods, and a listing of regulations. ATSDR, as mandated by CERCLA (or Superfund), prepares these profiles to inform and assist the public.
Inhalation pharmacokinetics of the environmental contaminants chloroform, bromodichloromethane, chlorodibromomethane, and carbon tetrachloride were evaluated, and their absorption amounts were estimated in rats to obtain fundamental data for risk assessment of chronic low-level exposures. Measured amounts of the substances were injected into a closed chamber system in which a rat had been placed, and the concentration changes in the chamber were examined. The pharmacokinetics of the substances were evaluated on the basis of the concentration-time courses using linear or nonlinear compartment models. The metabolic elimination amounts at various exposure concentrations were extrapolated using the estimated pharmacokinetic parameters. With exposure to chloroform, the fraction of the elimination amount at 1 ppb exposure (low concentration) against the exposure concentration was estimated to be 1.1 times higher than the fraction at 10 ppm exposure (high concentration). With exposure to low concentrations (1 ppb), extrapolation showed that more chloroform (0.33 nmol/h/kg) was absorbed by the rats than chlorodibromomethane (0.11 nmol/h/kg), bromodichloromethane (0.072 nmol/h/kg), and carbon tetrachloride (0.053 nmol/h/kg). Our findings revealed differences in the absorption amounts among the substances for the same exposure concentrations.
We performed measurements to determine indoor benzene levels in 26 residential houses in Kuwait, located in zones of different activity levels. Pumped (or active) sampling was conducted via use of 12 sampling tubes over a period of 24 hr for both indoor and outdoor concentrations simultaneously. Time-average indoor concentration varied linearly with time-average outdoor concentration in accordance with a mass-balance-based indoor air-quality model in which source and sink terms were incorporated. We used regression analysis to determine benzene adsorption rates, which appear in the removal and source terms of the model. The removal rate parameter varied between 0.12/hr and 2.16/hr, whereas source term parameter varied between 0.60 mg/hr and 76.07 mg/hr. Houses were then divided into three groups according to their benzene source strengths (i.e., < 1.0 mg/hr, 1-10 mg/hr, and 10-50 mg/hr). Qualitatively, these levels depended on the characteristics of occupants (e.g., smoking and gas cooker use, number of cars, and parking area) and location of the building.
Chloroform (CHCl3) the trihalomethane most prevalent in drinking water, is a proven animal carcinogen and a suspected human carcinogen. Consequently, standards have been issued by health authorities to limit its concentration in drinking water. These limits are based solely on ingestion, without taking into account inhalation and skin contact. Exposure to CHCl3 was assessed for 18 men (age: mean 38 years; range 23-51) following a 10-min shower in their respective residences located in the Quebec City region (Canada). CHCl3 concentration was measured in alveolar air samples collected before, immediately after, and 15 min and 30 min following the shower. Indoor air and water concentrations were determined concomitantly. Mean CHCl3 concentrations in the air of the shower stall and in water were respectively 147 microg/m3 (SD = 56.2 microg/m3) and 20.1 microg/L (SD = 9.0 microg/L). Water concentrations were comparable to those documented in a large proportion of distribution networks in Canada. The mean increase in alveolar air CHCl3 concentration (deltaCHCIALV) at the end of the shower was 33 microg/m3 (SD = 14.7 microg/m3). A multiple-regression analysis revealed that deltaCHCl3ALV values were only associated with chloroform concentration in air of the shower stall. DeltaCHCl3ALV were described using a physiologically based pharmacokinetic (PBPK) model. This model was then used to estimate concentrations of CHCl3 metabolites bound to liver and kidney macromolecules following a shower, and also according to exposure scenarios that integrate drinking-water ingestion and air inhalation. The concentration predicted in the liver following a worst-case exposure scenario was 0.41 microg CHCl3 equivalents/kg of tissue, some 6,000 times lower than the lowest concentration that did not increase the incidence of hepatic tumors in laboratory animals. Data indicate that for this range of exposure the safety margin appears therefore considerable with respect to the potential carcinogenic effect of household exposure to CHCl3.
Inhalation toxicokinetics of p-dichlorobenzene ( p-DCB) in humans was evaluated, and the amounts of daily absorption and internal accumulation were estimated in order to obtain fundamental data for the risk assessment of chronic low-level exposure in the general population. Seven male subjects continuously inhaled about 2.5 ppm of p-DCB vapor for 1 h, and the concentration-time courses of p-DCB in their exhaled air and serum and of urinary 2,5-dichlorophenol (2,5-DCP), a major metabolite of p-DCB, were examined. The toxicokinetics of p-DCB was evaluated on the basis of the time courses using a linear two-compartment model. The amounts of p-DCB absorbed daily and the internal accumulation in chronic low-level exposure were extrapolated using the estimated toxicokinetic parameters. p-DCB was transferred from inhaled air to the body with a constant high absorption rate during exposure. The major route for elimination from the body was urinary excretion followed by metabolism, not exhalation. However, during 9-11 h after the start of exposure, the fraction of p-DCB excreted in urine was only 5-16% of the amount absorbed. Furthermore, most of the absorbed p-DCB seemed to be distributed rapidly to the tissues, such as fat, according to toxicokinetic analysis. Consequently, p-DCB seems to require a long time to be completely eliminated from the body. The amounts of daily absorption and internal accumulation were extrapolated to average 0.27 mg/day and 2.9 mg, respectively, in the subjects exposed chronically to 1 ppb of p-DCB. The amount absorbed daily agreed approximately with that extrapolated from rats which inhaled p-DCB in our previous study.
All occupied buildings have various sources of indoor air pollution. Humans (and their household pets) generate carbon dioxide, moisture, odors, and microbes simply through normal living processes. Other more important sources of indoor air pollution are combustion appliances (gas stoves, unvented space heaters), building materials (used in construction, furnishings, and insulation), and soil under and around houses. These sources release carbn monoxide (CO), nitrogen dioxide (NOâ), formaldehyde (HCHO) and other organics, particulates, and radon. This paper discusses the sources and concentrations of organic compounds in indoor environments.