How to measure and evaluate volatile organic compound emissions from building products. A perspective

High-Resolution Exposure Assessment for Volatile Organic Compounds in Two California Residences

Time spent in residences substantially contributes to human exposure to volatile organic compounds (VOCs). Such exposures have been difficult to study deeply, in part because VOC concentrations and indoor occupancy vary rapidly. Using a fast-response online mass spectrometer, we report time-resolved exposures from multi-season sampling of more than 200 VOCs in two California residences. Chemical-specific source apportionment revealed that time-averaged exposures for most VOCs were mainly attributable to continuous indoor emissions from buildings and their static contents. Also contributing to exposures were occupant-related activities, such as cooking, and outdoor-to-indoor transport. Health risk assessments are possible for a subset of observed VOCs. Acrolein, acetaldehyde, and acrylic acid concentrations were above chronic advisory health guidelines, whereas exposures for other assessable species were typically well below the guideline levels. Studied residences were built in the mid-20th century, indicating that VOC emissions even from older buildings and their contents can substantially contribute to occupant exposures.

Indoor gaseous air pollutants determinants in office buildings-The OFFICAIR project

The aim of this study was to identify determinants of aldehyde and volatile organic compound (VOC) indoor air concentrations in a sample of more than 140 office rooms, in the framework of the European OFFICAIR research project. A large field campaign was performed, which included (a) the air sampling of aldehydes and VOCs in 37 newly built or recently retrofitted office buildings across 8 European countries in summer and winter and (b) the collection of information on building and offices' characteristics using checklists. Linear mixed models for repeated measurements were applied to identify the main factors affecting the measured concentrations of selected indoor air pollutants (IAPs). Several associations between aldehydes and VOCs concentrations and buildings' structural characteristic or occupants' activity patterns were identified. The aldehyde and VOC determinants in office buildings include building and furnishing materials, indoor climate characteristics (room temperature and relative humidity), the use of consumer products (eg, cleaning and personal care products, office equipment), as well as the presence of outdoor sources in the proximity of the buildings (ie, vehicular traffic). Results also showed that determinants of indoor air concentrations varied considerably among different type of pollutants.

VOC Emissions from Spruce Strands and Hemp Shive: In Search for a Low Emission Raw Material for Bio-Based Construction Materials

Volatile organic compounds (VOCs) reduce indoor air quality. They are associated with negative effects on human health and wellbeing. In terms of legislation requirements and consumer pressure, VOCs from engineered wood materials are reduced due to use of water based additives and adhesives in their formulation. Therefore, the main source of VOCs remains the raw material—the wood itself. Alternatives to wood strands, annual plant materials, are tested nowadays due to their advantages: The short cycle; the raw material is sourced naturally and can be produced more sustainably; and faster sequestering atmospheric carbon. The aim of this work was to investigate volatile organic compounds emitted from untreated and chemically treated hemp shive and compare the emission characteristics to soft wood strands. Simple, yet effective chemical treatments, like tartaric acid, citric acid and sodium bicarbonate were used in order to reduce VOC emissions. Gas chromatography-mass spectrometry (GC-MS) combined with headspace solid-phase microextraction (HS-SPME) was used to analyse the volatile compounds emissions. Specific VOCs like acetic acid; Benzaldehyde; hexanal, α-, β-pinenes; limonene and camphene were monitored before and after the treatments. Non-target screening was performed to identify the most responsible compound for differentiation of samples according to their treatments. Comparing untreated samples, spruce strands showed highest amounts of total VOCs, while untreated hemp shive showed the lowest. Further, due to the chemical modification of hemp woody core components, such as hemicelluloses, lignin, and extractives, the key VOCs showed significant changes leading to an increase in the amount of total emissions.

Sick Building Syndrome and Other Building-Related Illnesses

Sick building syndrome (SBS) and building-related illnesses are omnipresent in modern high-rise buildings. The SBS is a complex spectrum of ill health symptoms, such as mucous membrane irritation, asthma, neurotoxic effects, gastrointestinal disturbance, skin dryness, sensitivity to odours that may appear among occupants in office and public buildings, schools and hospitals. Studies on large office buildings from USA, UK, Sweden, Finland, Japan, Germany, Canada, China, India, Netherlands, Malaysia, Taiwan, and Thailand, substantiate the occurrence of SBS phenomena. The accumulated effects of a multitude of factors, such as the indoor environmental quality, building characteristics, building dampness, and activities of occupants attribute to SBS. A building occupant manifests at least one symptom of SBS, the onset of two or more symptoms at least twice, and rapid resolution of symptoms following moving away from the workstation or building may be defined as having SBS. Based on the peer-reviewed documentation, this chapter elaborates the magnitude of building-related health consequences due to measurable environmental causations, and the size of the population affected. The mechanisms and causative factors of SBS and illnesses include, for example, the oxidative stress resulting from indoor pollutants, VOCs, office work-related stressors, humidification, odours associated with moisture and bioaerosol exposure. Related regulatory standards and strategies for management of SBS and other illnesses are elaborated.

Indoor Air Quality: A Bibliometric Study

What are the actual trends in Indoor Air Quality (IAQ), and in which direction is academic interest moving? Much progress has been made in identifying and mitigating indoor pollutants, due to both prevention campaigns (e.g., smoking bans) and greater control of product emissions. However, IAQ is still of interest and the future trends are unknown. In this study, a thorough bibliometric analysis was conducted on the scientific literature available on the Web of Science database with CiteSpace from 1990 until today. It was possible to identify past trends and current advances, both with the aim of introducing the IAQ topic to those encountering it for the first time and to examine the issues that are expected to be pertinent in the future.

Predictors of blood volatile organic compound levels in Gulf coast residents

To address concerns among Gulf Coast residents about ongoing exposures to volatile organic compounds, including benzene, toluene, ethylbenzene, o-xylene, and m-xylene/p-xylene (BTEX), we characterized current blood levels and identified predictors of BTEX among Gulf state residents. We collected questionnaire data on recent exposures and measured blood BTEX levels in a convenience sample of 718 Gulf residents. Because BTEX is rapidly cleared from the body, blood levels represent recent exposures in the past 24 h. We compared participants' levels of blood BTEX to a nationally representative sample. Among nonsmokers we assessed predictors of blood BTEX levels using linear regression, and predicted the risk of elevated BTEX levels using modified Poisson regression. Blood BTEX levels in Gulf residents were similar to national levels. Among nonsmokers, sex and reporting recent smoky/chemical odors predicted blood BTEX. The change in log benzene was -0.26 (95% CI: -0.47, -0.04) and 0.72 (0.02, 1.42) for women and those who reported odors, respectively. Season, time spent away from home, and self-reported residential proximity to Superfund sites (within a half mile) were statistically associated with benzene only, however mean concentration was nearly an order of magnitude below that of cigarette smokers. Among these Gulf residents, smoking was the primary contributor to blood BTEX levels, but other factors were also relevant.

An indoor air quality evaluation in a residential retrofit project using spray polyurethane foam

Understanding of indoor air quality (IAQ) during and after spray polyurethane foam (SPF) application is essential to protect the health of both workers and building occupants. Previous efforts such as field monitoring, micro-chamber/spray booth emission studies, and fate/transport modeling have been conducted to understand the chemical exposure of SPF and guide risk mitigation strategies. However, each type of research has its limitation and can only reveal partial information on the relationship between SPF and IAQ. A comprehensive study is truly needed to integrate the experimental design and analytical testing methods in the field/chamber studies with the mathematical tools employed in the modeling studies. This study aims to bridge this gap and provide a more comprehensive understanding on the impact of SPF to IAQ. The field sampling plan of this research aims to evaluate the airborne concentrations of methylene diphenyl diisocyanate (MDI), formaldehyde, acetaldehyde, propionaldehyde, tris(1-chlor-2-propyl)phosphate (TCPP), trans-1-chloro-3,3,3-trifluoropropene (Solstice^TM), and airborne particles. Modifications to existing MDI sampling and analytical methods were made so that level of quantification was improved. In addition, key fate and transport modeling input parameters such as air changes per hour and airborne particle size distribution were measured. More importantly, TCPP accumulation onto materials was evaluated, which is important to study the fate and transport of semi-volatile organic compounds. The IAQ results showed that after spray application was completed in the entire building, airborne concentrations decreased for all chemicals monitored. However, it is our recommendation that during SPF application, no one should return to the application site without proper personal protection equipment as long as there are active spray activities in the building. The comparison between this field study and a recent chamber study proved surface sorption and particle deposition is an important factor in determining the fate of airborne TCPP. The study also suggests the need for further evaluation by employing mathematical models, proving the data generated in this work as informative to industry and the broader scientific community.

Do time-averaged, whole-building, effective volatile organic compound (VOC) emissions depend on the air exchange rate? A statistical analysis of trends for 46 VOCs in U.S. offices

We used existing data to develop distributions of time-averaged air exchange rates (AER), whole-building 'effective' emission rates of volatile organic compounds (VOC), and other variables for use in Monte Carlo analyses of U.S. offices. With these, we explored whether long-term VOC emission rates were related to the AER over the sector, as has been observed in the short term for some VOCs in single buildings. We fit and compared two statistical models to the data. In the independent emissions model (IEM), emissions were unaffected by other variables, while in the dependent emissions model (DEM), emissions responded to the AER via coupling through a conceptual boundary layer between the air and a lumped emission source. For 20 of 46 VOCs, the DEM was preferable to the IEM and emission rates, though variable, were higher in buildings with higher AERs. Most oxygenated VOCs and some alkanes were well fit by the DEM, while nearly all aromatics and halocarbons were independent. Trends by vapor pressure suggested multiple mechanisms could be involved. The factors of temperature, relative humidity, and building age were almost never associated with effective emission rates. Our findings suggest that effective emissions in real commercial buildings will be difficult to predict from deterministic experiments or models.

VOCs Emissions from Multiple Wood Pellet Types and Concentrations in Indoor Air

Wood pellet storage safety is an important aspect for implementing woody biomass as a renewable energy source. When wood pellets are stored indoors in large quantities (tons) in poorly ventilated spaces in buildings, such as in basements, off-gassing of volatile organic compounds (VOCs) can significantly affect indoor air quality. To determine the emission rates and potential impact of VOC emissions, a series of laboratory and field measurements were conducted using softwood, hardwood, and blended wood pellets manufactured in New York. Evacuated canisters were used to collect air samples from the headspace of drums containing pellets and then in basements and pellet storage areas of homes and small businesses. Multiple peaks were identified during GC/MS and GC/FID analysis, and four primary VOCs were characterized and quantified: methanol, pentane, pentanal, and hexanal. Laboratory results show that total VOCs (TVOCs) concentrations for softwood (SW) were statistically (p < 0.02) higher than blended or hardwood (HW) (SW: 412 ± 25; blended: 203 ± 4; HW: 99 ± 8, ppb). The emission rate from HW was the fastest, followed by blended and SW, respectively. Emissions rates were found to range from 10^-1 to 10^-5 units, depending upon environmental factors. Field measurements resulted in airborne concentrations ranging from 67 ± 8 to 5000 ± 3000 ppb of TVOCs and 12 to 1500 ppb of aldehydes, with higher concentrations found in a basement with a large fabric bag storage unit after fresh pellet delivery and lower concentrations for aged pellets. These results suggest that large fabric bag storage units resulted in a substantial release of VOCs into the building air. Occupants of the buildings tested discussed concerns about odor and sensory irritation when new pellets were delivered. The sensory response was likely due to the aldehydes.

Influence of relative humidity on VOC concentrations in indoor air

Volatile organic compounds (VOCs) may be emitted from surfaces indoors leading to compromised air quality. This study scrutinized the influence of relative humidity (RH) on VOC concentrations in a building that had been subjected to water damage. While air samplings in a damp room at low RH (21-22%) only revealed minor amounts of 2-ethylhexanol (3 μg/m(3)) and 2,2,4-trimethyl-1,3-pentanediol diisobutyrate (TXIB, 8 μg/m(3)), measurements performed after a rapid increase of RH (to 58-75%) revealed an increase in VOC concentrations which was 3-fold for 2-ethylhexanol and 2-fold for TXIB. Similar VOC emission patterns were found in laboratory analyses of moisture-affected and laboratory-contaminated building materials. This study demonstrates the importance of monitoring RH when sampling indoor air for VOCs in order to avoid misleading conclusions from the analytical results.

Behavior of VOCs and carbonyl compounds emission from different types of wallpapers in Korea

Emissions of volatile organic compounds (VOCs) and carbonyls from three types of commercially available wallpapers (i.e., PVC-coated, paper-backed, natural material-coated) in Korea were evaluated using a 20 L small chamber. A total of 332 products were tested for emission factors, frequencies of occurrence and composition ratios. Toluene and formaldehyde concentrations were below Korean standard values for all products; however, the total VOC (TVOC) concentrations exceeded current standards (4.0 mg/m²·h) for 30 products. The TVOC emission factor for PVC-coated wallpapers, for which polymer materials are used in the manufacturing process, was seven and 16 times higher than those of paper-backed and natural material-coated wallpapers, respectively. The detection frequencies for toluene and formaldehyde were the highest (82.5%) and fourth highest (79.5%), respectively among the 50 target chemical species. The composition ratios for BTEX ranged from 0.3% to 5.1% and unidentified VOCs, which were not qualitatively analyzed using standard gas methods, ranged from 90.2% to 94.8%. Among six carbonyl compounds (acrolein was not detected in any type of wallpaper), acetone had the highest concentrations in PVC-coated (44.6%) and paper-backed (66.6%) wallpapers. Formaldehyde emissions were highest (64.6%) for natural material-coated wallpapers, a result of the formaldehyde-based resin used in the manufacturing process for these products.

Longitudinal variations in indoor VOC concentrations after moving into new apartments and indoor source characterization

This study examined the indoor concentrations of a wide range of volatile organic compounds (VOCs) in currently built new apartments every month over a 24-month period and the source characteristics of indoor VOCs. The indoor total VOC (TVOC) concentrations exhibited a decreasing tendency over the 24-month follow-up period. Similar to TVOCs, the median indoor concentrations of 33 of 40 individual VOCs (all except for naphthalene and six halogenated VOCs) revealed decreasing tendencies. In contrast, the indoor concentrations of the six halogenated VOCs did not reveal any definite trend with time. Moreover, the indoor concentrations of those halogenated VOCs were similar to the outdoor concentrations, suggesting the absence of any notable indoor sources of halogenated VOCs. For naphthalene (NT), the indoor concentrations were significantly higher than the outdoor concentrations, suggesting the presence of indoor NT source(s). The floor/wall coverings (39 %) were the most influential indoor source of indoor VOCs, followed by household cleaning products (32 %), wood paneling/furniture (17 %), paints (7 %), and moth repellents (5 %).

Volatile organic compound concentrations, emission rates, and source apportionment in newly-built apartments at pre-occupancy stage

The present study investigated the indoor concentrations of selected volatile organic compounds (VOCs) and formaldehyde and their indoor emission characteristics in newly-built apartments at the pre-occupancy stage. In total, 107 apartments were surveyed for indoor and outdoor VOC concentrations in two metropolitan cities and one rural area in Korea. A mass balanced model was used to estimate surface area-specific emission rates of individual VOCs and formaldehyde. Seven (benzene, ethyl benzene, toluene, m,p-xylene, o-xylene, n-hexane, and n-heptane) of 40 target compounds were detectable in all indoor air samples, whereas the first five were detected in all outdoor air samples. Formaldehyde was also predominant in the indoor air samples, with a high detection frequency of 96%. The indoor concentrations were significantly higher than the outdoor concentrations for aromatics, alcohols, terpenes, and ketones. However, six halogenated VOCs exhibited similar concentrations for indoor and outdoor air samples, suggesting that they are not major components emitted from building materials. It was also suggested that a certain portion of the apartments surveyed were constructed by not following the Korean Ministry of Environment guidelines for formaldehyde emissions. Toluene exhibited the highest emission rate with a median value of 138 μg m(-2) h(-1). The target compounds with median emission rates greater than 20 μg m(-2) h(-1) were toluene, 1-propanol, formaldehyde, and 2-butanone. The wood panels/vinyl floor coverings were the largest indoor pollutant source, followed by floorings, wall coverings, adhesives, and paints. The wood panels/vinyl floor coverings contributed nearly three times more to indoor VOC concentrations than paints.

Indoor air pollutants in office environments: assessment of comfort, health, and performance

Concentrations of volatile organic compounds (VOCs) in office environments are generally too low to cause sensory irritation in the eyes and airways on the basis of estimated thresholds for sensory irritation. Furthermore, effects in the lungs, e.g. inflammatory effects, have not been substantiated at indoor relevant concentrations. Some VOCs, including formaldehyde, in combination may under certain environmental and occupational conditions result in reported sensory irritation. The odour thresholds of several VOCs are low enough to influence the perceived air quality that result in a number of acute effects from reported sensory irritation in eyes and airways and deterioration of performance. The odour perception (air quality) depends on a number of factors that may influence the odour impact. There is neither clear indication that office dust particles may cause sensory effects, even not particles spiked with glucans, aldehydes or phthalates, nor lung effects; some inflammatory effects may be observed among asthmatics. Ozone-initiated terpene reaction products may be of concern in ozone-enriched environments (≥0.1mg/m(3)) and elevated limonene concentrations, partly due to the production of formaldehyde. Ambient particles may cause cardio-pulmonary effects, especially in susceptible people (e.g. elderly and sick people); even, short-term effects, e.g. from traffic emission and candle smoke may possibly have modulating and delayed effects on the heart, but otherwise adverse effects in the airways and lung functions have not been observed. Secondary organic aerosols generated in indoor ozone-initiated terpene reactions appear not to cause adverse effects in the airways; rather the gaseous products are relevant. Combined exposure to particles and ozone may evoke effects in subgroups of asthmatics. Based on an analysis of thresholds for odour and sensory irritation selected compounds are recommended for measurements to assess the indoor air quality and to minimize reports of irritation symptoms, deteriorated performance, and cardiovascular and pulmonary effects.

Evaluation of formaldehyde and VOCs emission factors from paints in a small chamber: the effects of preconditioning time and coating weight

The aims of this study were to improve the emission test method for the 20 L small chamber standardized in Korea using paints and to develop an optical test method for paints. The emission factors of the total volatile organic compounds (TVOC) and formaldehyde from oil-based paints, emulsion paints and water-dispersion paints coated at 300 g/m(2) and cured for 24 (48)h were determined using the 20 L small chamber method. The emission factors of TVOC and formaldehyde from all paints under steady state conditions were determined after 7 days with 24 (48)h of curing. The Korean standards require that paints be measured and analyzed on the third day after a test. However, the emission factors of TVOC and formaldehyde from the paints only began to stabilize 7 days after installing the samples. Until now, the emission test results have been reported mainly as concentration vs. time or emission factor vs. time profiles of TVOC and formaldehyde. The emission factors of the target volatile organic compounds (VOCs) and aldehyde types were obtained under specific test conditions according to the different coating weights. For all target volatile organic compounds and aldehyde types examined, the paint coating weight had an effect on emission.

Ozone-surface reactions in five homes: surface reaction probabilities, aldehyde yields, and trends

Field experiments were conducted in five homes during three seasons (summer 2005, summer 2006 and winter 2007) to quantify ozone-initiated secondary aldehyde yields, surface reaction probabilities, and trends any temporal over a 1.5-year interval. Surfaces examined include living room carpets, bedroom carpets, kitchen floors, kitchen counters, and living room walls. Reaction probabilities for all surfaces for all seasons ranged from 9.4 x 10(-8) to 1.0 x 10(-4). There were no significant temporal trends in reaction probabilities for any surfaces from summer 2005 to summer 2006, nor over the entire 1.5-year period, indicating that it may take significantly longer than this period for surfaces to exhibit any 'ozone aging' or lowering of ozone-surface reactivity. However, all surfaces in three houses exhibited a significant decrease in reaction probabilities from summer 2006 to winter 2007. The total yield of aldehydes for the summer of 2005 were nearly identical to that for summer of 2006, but were significantly higher than for winter 2007. We also observed that older carpets were consistently less reactive than in newer carpets, but that countertops remained consistently reactive, probably because of occupant activities such as cooking and cleaning.

PRACTICAL IMPLICATIONS

Ozone reactions taking place at indoor surfaces significantly influence personal exposure to ozone and volatile reaction products. These field studies show that indoor surfaces only slowly lose their ability to react with ozone over several year time frames, and that this is probably because of a combination of large reservoirs of reactive coatings and periodic additions of reactive coatings in the form of cooking, cleaning, and skin-oil residues. When considering exposure to ozone and its reaction products and in the absence of dramatic changes in occupancy, activities or furnishings, indoor surface reactivity is expected to change very slowly.

Decreasing concentrations of volatile organic compounds (VOC) emitted following home renovations

Volatile organic compounds (VOC) play an important role indoors since they have been linked to health symptoms and disorders. Particularly, after renovation activities, high indoor VOC concentrations have been observed. The study will give an indication, for the first time under real conditions, of the to-be-expected time frame for renovation-derived indoor pollution decreases when the exposure to it will reach a reference level. The decrease in the concentrations of investigated 26 VOC after renovations was assessed under real-life situations. Both the daily VOC concentration was measured by active sampling for 30 days in selected homes which had undergone various renovations and, as part of an epidemiologic study, the same VOC were collected monthly using passive samplers in 243 homes. An exponential function was used to interpret the concentration decay. The average time range which has to elapse following renovation activities before a guideline value or reference load is reached showed a time range between 2 and 8 weeks. This waiting time had at least be applicable to public buildings and institutions (especially relevant in case of nurseries, playschools etc.) with increasingly being implemented in private homes as well. Practical Implications After renovation an optimal waiting period had to be up to 60 days before the rooms will be used again. Fourteen days are possible, but increased ventilation is recommended. These had to be applicable at least for public buildings used by risk groups like young children. Renovations had to be carried out in summer season to ensure optimal ventilation to reduce the waiting time.

Effects on perceived air quality and symptoms of exposure to microbially produced metabolites and compounds emitted from damp building materials

This work investigated perceived air quality and health effects from exposure to low to high levels of volatile organic compounds (VOCs) emitted from damp building materials and a mixture of molds growing on the materials. A mixture of Wallemia sebi, Fusarium culmorum, Penicillium chrysogenum, Ulocladium botrytis, and Aspergillus versicolor was inoculated on pine wood and particle board. In Study 1, each of 27 participants took part in two exposure conditions, one with air from molds growing on building materials (low levels of emissions from the building materials and the mold mixture) and one with blank air, both conditions during 60 min. In Study 2, each of 24 participants was exposed (10 min) four times in a 2 x 2 design randomly to air from moldy building materials (high levels) and blank, with and without nose-clip. The participants rated air quality and symptoms before, during, and after each exposure. Self-reported tear-film break-up time and attention and processing speed (Study 1) was also measured. Exposure to high VOC levels increased the reports of perceived poor air quality, and in the condition without nose-clip enhanced skin symptoms were also noted. No such outcome was observed when exposing the participants to low VOC levels.

PRACTICAL IMPLICATIONS

Emissions from building materials caused by dampness and microbial growth may be involved in indoor air health problems. This study showed that exposure to high levels of VOC emitted from damp building materials and a mixture of mold may cause perceived poor air quality. It also indicated that stimulation of chemical warning systems (the nasal chemosensory part of the trigeminal system and the olfactory system) may enhance skin symptoms.

The dichotomy of relative humidity on indoor air quality

Dry and irritated mucous membranes of the eyes and airways are common symptoms reported in office-like environments. Earlier studies suggested that indoor pollutants were responsible. We have re-evaluated, by review of the literature, how low relative humidity (RH) may influence the immediately perceived indoor air quality (IAQ), including odour, and cause irritation symptoms (i.e. longer-term perceived IAQ). "Relative humidity" were searched in major databases, and combined with: air quality, cabin air, dry eyes, formaldehyde, inflammation, mucous membranes, offices, ozone, pungency, sensory irritation, particles, precorneal tear film, sick building syndrome, stuffy air, and VOCs. The impact of RH on the immediately and longer-term perceived IAQ by VOCs, ozone, and particles is complex, because both the thermodynamic condition and the emission characteristics of building materials are influenced. Epidemiological, clinical, and human exposure studies indicate that low RH plays a role in the increase of reporting eye irritation symptoms and alteration of the precorneal tear film. These effects may be exacerbated during visual display unit work. The recommendation that IAQ should be "dry and cool" may be useful for evaluation of the immediately perceived IAQ in material emission testing, but should be considered cautiously about the development of irritation symptoms in eyes and upper airways during a workday. Studies indicate that RH about 40% is better for the eyes and upper airways than levels below 30%. The optimal RH may differ for the eyes and the airways regarding desiccation of the mucous membranes.

Volatile organic compounds (VOCs) emitted from materials collected from buildings affected by microorganisms

In this study mould damaged materials, including carpet, concrete, gypsum board, insulation, plastic, sand and wood, from 20 different buildings with moisture problems were collected. To study emissions from these materials both conventional methods for sampling, such as collection on Tenax TA, were used as well as complementary methods for sampling a wider spectrum of compounds, such as more volatile VOCs, amines and aldehydes. Analysis was carried out using gas chromatography and high-performance liquid chromatography. Mass spectrometry was used for identification of compounds. Alcohols and ketones were almost exclusively emitted from the materials after they had been wet for a week. Acids were also emitted in large quantities from wet gypsum board and plastic. No primary or secondary amines could be identified, but two tertiary amines, trimethylamine and triethylamine, were emitted from sand contaminated by Bacillus. The most common moulds found were Penicillium and Aspergillus. A multivariate method (partial least squares, PLS) was used to investigate the emission patterns from the materials. Materials with bacterial growth had a different VOC profile to those with only mould growth.

Volatile organic compounds: do they present a risk to our health?

Indoor air quality has been recognised as a significant health, environment, and economic issue in many countries. Research findings have demonstrated that some air pollutants occur more frequently and at a higher concentration in indoor air than in outdoor air, including volatile organic compounds (VOCs). In this context, the indoor environment can be of crucial importance because modem society spends most of their time indoors, and exposure to VOCs may result in a spectrum of illnesses ranging from mild, such as irritation, to very severe effects, including cancer. These effects have been seen at very low levels of exposure in many epidemiological studies. In this review, we discuss the nature of the VOCs that are ubiquitous in indoor environment and the evidence for adverse health effects associated with exposure to some of these compounds.

New approach to environmental tobacco smoke exposure and its relation to reemission processes

Indoor air quality is one of the factors that determine human well-being and health. Being aware of this fact, it is essential to identify the origin, kind, mechanism, and effects of harmful substances contained in the air. The issue concerning the contents and primary emission of these substances from building materials and interior furnishings is well known. Adverse effects of environmental tobacco smoke (ETS), including exposure of passive smokers, are also very well documented. To the contrary, reports on secondary and indirect emissions, especially those focused on mechanisms by which pollution is "transferred" by materials used in interior furnishings are very rare. Textiles are used in a great variety of ways as functional and decorative materials. These materials in general, and textile floor coverings in particular, are extensively utilized in fitting apartments, public buildings, and transport means. Studies on this aspect of the role played by textile materials in ETS exposure have been only fragmentary documented.

Methyl benzoate as a marker for the detection of mold in indoor building materials

A convenient analytical method to quantify volatile organic compounds (VOCs) emitted from various building materials has not been addressed yet. This work presents a new and rapid automated method using SPME combined with GC/MS. Methyl benzoate - as a metabolic biomarker for mold growth-was used to indicate VOCs and to determine and assess mold growth on damp samples. Gypsum board and wall-board paper were used as examples of common indoor building materials. Optimized extraction conditions were carried out manually, using a GC/flame ionization detector. Moldy samples were analyzed using an automated SPME-GC/MS analysis under optimized conditions. The amount of methyl benzoate emitted from the studied samples ranged from 32 to 46 ppb, where the density of the fungal biomass was found to be 8 x 10(4) cells/mL. A relationship between the amount of fungal biomass and the emitted concentration of methyl benzoate was found and assessed based upon cultured mold samples taken from indoor building sites. The analytical method shows promise for the compound methyl benzoate, which can easily be identified at low detection limits (LOD = 3 ppb) and good linearity (>0.988), and its extraction and detection can be accomplished cleanly by current extraction techniques. Results suggest that this method with easy sample preparation can be used for quantitation and, of importance, minimal matrix effects are observed.

Organic compounds in office environments - sensory irritation, odor, measurements and the role of reactive chemistry

Abstract Sensory irritation and odor effects of organic compounds in indoor environments are reviewed. It is proposed to subdivide volatile organic compounds (VOCs) into four categories: (i) chemically non-reactive, (ii) chemically 'reactive', (iii) biologically reactive (i.e. form chemical bonds to receptor sites in mucous membranes) and (iv) toxic compounds. Chemically non-reactive VOCs are considered non-irritants at typical indoor air levels. However, compounds with low odor thresholds contribute to the overall perception of the indoor air quality. Reported sensory irritation may be the result of odor annoyance. It appears that odor thresholds for many VOCs probably are considerably lower than previously reported. This explains why many building materials persistently are perceived as odorous, although the concentrations of the detected organic compounds are close to or below their reported odor thresholds. Ozone reacts with certain alkenes to form a gas and aerosol phase of oxidation products, some of which are sensory irritants. However, all of the sensory irritating species have not yet been identified and whether the secondary aerosols (ultrafine and fine particles) contribute to sensory irritation requires investigation. Low relative humidity may exacerbate the sensory irritation impact. Practical Implications Certain odors, in addition to odor annoyance, may result in psychological effects and distraction from work. Some building materials continually cause perceivable odors, because the odor thresholds of the emitted compounds are low. Some oxidation products of alkenes (e.g. terpenes) may contribute to eye and airway symptoms under certain conditions and low relative humidity.

Emission patterns and emission rates of MVOC and the possibility for predicting hidden mold damage?

Laboratory trials were performed in order to search for the variety of the production of microbial volatile organic compounds (MVOC), which could be used as indicators for hidden mold damage. Concerning MVOC production the experiments showed a dependency on the mold genus/species, the different strains used and the building materials used as substrate. It could be proved that the production of certain MVOC is not consistent at all times. On the whole low emission rates in terms of microg/h/m2 of the MVOC were found. Extrapolating the emissions rates from the laboratory trails to an indoor air situation results in concentrations below the analytical detection limit in most cases. According to these results only heavy or very large fungal contaminations might be detected by this method in indoor air. The studies were performed at the Institute of Hygiene and Environmental Medicine, Charite, Germany.

PRACTICAL IMPLICATIONS

Microorganisms like bacteria and molds produce a huge variety of substances, and a part of them are released into the environment. Some compounds like, e.g. alcohols or ketones are volatile, therefore found in the air and called MVOC. Those compounds were considered helpful to track especially hidden mold damage. The study presented here showed, that the emission pattern varies from genus to genus and sometimes even from fungal strain to fungal strain. The results concerning the emission rates from different infested building materials proved, that the concentrations produced are much too low to be detected in indoor air, especially considering the dilution because of ventilation. Therefore, we conclude that MVOC should not be used as predictors for mold damage in indoor environments.

Speciation of volatile aromatic and chlorinated hydrocarbons in an urban atmosphere using TCT-GC/MS

Several aromatic and chlorinated volatile hydrocarbons (VOCs) were measured in Vitoria-Gasteiz City (Spain) throughout the years 1999 and 2002 in order to find out the concentration of these pollutants in urban air. These VOCs were retained in Tenax TA, subsequently desorpted by using a thermal desorption cold trap injector (TCT), and thereafter analyzed by gas chromatography/mass spectrometry (GC/MS). This analytical methodology permits the determination of 42 VOCs at very low concentrations, although only 32 of them were found in the urban air of the city (ranging from 205.51 to 0.01 microg m(-3)), with high reproducibility (%RSD lower than 10%). Twenty-four-hour samples were taken each sampling day to ascertain their total daily concentration, and rigorous quality controls were carried out to check the representativeness of sampling. Results of this exhaustive study show that toluene (T), xylenes (X), ethylbenzene (E), and benzene (B) were, respectively, the most abundant of these VOCs in the urban area during that period. The total concentration of BTEX represented, on average, more than 72.6% of the VOC total concentration, with the highest concentrations being reached in autumn, except for benzene and derived compounds (in winter). Benzene was the minority BTEX pollutant, its yearly mean concentration being less than the maximum established by the European Directive 2000/69/CE (5 microg m(-3)).

Sensory evaluation of emissions from selected building products exposed to ozone

The interaction of ozone with eight different building products was studied in test chambers. The products were plasterboard, two types of paints on plasterboard, two types of carpet, linoleum, pinewood, and melamine-covered particleboard. Four months of conditioning prior to the experiment had left the products with a low emission. The products' ability to remove ozone from the air covered a wide range. For three of the products (plasterboard with paint, carpet, and pinewood), it was shown that the removal was primarily due to interactions in the products' surfaces and only to a minor extent due to gas-phase reactions. Sensory evaluations were carried out for five of the products, with different ozone-removal potentials. A sensory panel assessed the emissions from sets of two specimens of each product; one specimen was exposed to a high, but realistic, ozone concentration (10 or 80 ppb) and one specimen was exposed to no ozone (background level < 3 ppb). The panel assessed odor intensity and was asked to choose which odor of the two specimens they preferred. The perceivable changes in emissions due to exposure of the products to ozone depended on the type of product. The greatest effect was seen for carpet. Carpet was the only product that showed significantly higher odor intensity when exposed to ozone. Besides, the effect of ozone on preference was strongest for carpet and resulted in a clear negative sensory evaluation. A similar but less pronounced effect was seen for pinewood and plasterboard with paint. No clear preference was seen for melamine and linoleum.

Trends in Europe to reduce the indoor air pollution of VOCs

A strong research tradition in the European countries about volatile organic compounds (VOCs) and indoor air quality has led to several consensus reports about stategies for VOC measurements including the development of methods to measure VOC emissions from building products. European and Nordic standards have been developed for emission testing including several national and international labeling schemes. Proposals for guidelines for a number of different VOCs have been developed either nationally or by consensus. A compound-by-compound approach for health evaluation of VOCs has become more common and there appears to be a growing recognition to focus on the biologic relevance of organic compounds in indoor air (OCIAs).

Redecoration of apartments promotes obstructive bronchitis in atopy risk infants--results of the LARS Study

Findings by other authors indicate that exposure to chemical emissions from indoor paint is related to asthma symptoms in adults. In their first years of life children are receptive to obstructive airway diseases. The aim of this study was to investigate the influence of redecoration of the apartment on airway symptoms in infants during the first two years of life. The Leipzig Allergy Risk Children Study (LARS) is a birth cohort study with the following inclusion criteria: double positive family atopy anamnesis, cord blood IgE > 0.9 kU/l, or low birth weight between 1500-2500 g. Within the context of LARS, 186 parents of risk children completed a questionnaire on the respiratory symptoms of their children and the redecoration of their apartment at the end of the first and second year of life. A total 22% of the children suffered from obstructive bronchitis once or more during their first year, and 11% experienced this condition during their second year of life. Redecoration of the apartment had a significant influence on the appearance of obstructive bronchitis in the first (OR 4.1 95% CI 1.4-11.9) and in the second year of life (OR 4.2 95% CI 1.4-12.9). (The OR are adjusted for cord blood-IgE > 0.9 kU/l, birth weight < or = 2500 g, male sex and double positive parental atopy anamnesis, dampness, smoking or pet in the apartment). Simultaneous contamination from redecoration activities and additional exposures such as smoking, a pet or dampness in the apartment increased the risk for obstructive bronchitis in the first year (OR 9.1; 95% CI 2.3-34.8) as well as in the second year (OR 5.1; 95% CI 1.6-15.6). Our data suggest that redecoration of the apartment is associated with the development of acute inflammations, but not with a chronic influence on the airways in atopy risk infants. At an exposure to more than one environmental factor, pronounced effects were seen.

Ozone interactions with carpet: secondary emissions of aldehydes

Ozone-induced formation of aldehydes was studied on the surface and in the gas phase above carpets and on carpet components. Samples of four carpets were exposed to 100 ppb ozone. Emission rates of aldehydes and other organic compounds were measured from exposed and unexposed samples. Surface interactions of ozone with carpets produced C1-C13 n-aldehydes and several unsaturated aldehydes. Total aldehyde emission rates increased markedly with ozone exposure, from 1 to 70 microg m(-2) h(-1) for unexposed samples, to 60-800 microg m(-2) h(-1) during exposure. One exposed sample emitted large amounts of 2-nonenal (180-230 microg m(-2) h(-1)), a compound with a low odor threshold. Material balance modeling of a residence with this high emitting carpet suggests (1) that the concentration of 2-nonenal would be well above its odor threshold even in areas with only moderate ambient ozone levels and (2) that odorous levels of 2-nonenal could persist for years. Reactions of ozone with gas-phase primary emissions from carpet significantly reduced the levels of 4-phenylcyclohexene and produced small amounts of branched ketones. Separately measured patterns of aldehyde emissions from ozone exposure of linseed and tung oils were similar but not identical to those observed from ozone-exposed carpets.

Determination of ozone removal rates by selected building products using the FLEC emission cell

Ozone removal by 16 aged (older than 1-120 months) but unused building products or materials was studied in a test system that included the field and laboratory emission cell (FLEC). The ozone removal was studied at 50 +/- 1 ppb ozone, a relative humidity of 50 +/- 5%, a temperature of 21 +/- 2 degrees C, and an air flow rate of 900 +/- 10 mL min(-1) through the FLEC (air velocity ca. 3 cm s(-1)). The ozone removal increased rapidly during the first 1-2 min and either remained at a constant level or decreased asymptotically to reach a steady state-like value. The ozone removal profiles for a given material showed good repeatability during replicate experiments. Ozone deposition velocities for the building products were calculated to be between 0.0007 cm s(-1) (lacquered ash) and 0.8 cm s(-1) (unpainted gypsum board).