Volatile organic compounds from building products—Results from six round robin tests with emission test chambers conducted between 2008 and 2018

Emission testing of volatile organic compounds (VOC) from materials and products is commonly based on emission test chamber measurements. To ensure the comparability of results from different testing laboratories, their measurement performance must be verified. For this purpose, Bundesanstalt für Materialforschung und -prüfung (BAM) organizes an international proficiency test (round robin test, RRT) every two years using well-characterized test materials (one sealant, one furniture board, and four times a lacquer) with defined VOC emissions. The materials fulfilled the requirements of homogeneity, reproducibility, and stability. Altogether, 36 VOCs were included of which 33 gave test chamber air concentrations between 13 and 83 µg/m³. This is the typical concentration range to be expected and to be quantified when performing chamber tests. Three compounds had higher concentrations between 326 and 1105 µg/m³. In this paper, the relative standard deviations (RSD) of BAM round robin tests since 2008 are compared and the improvement of the comparability of the emission chamber testing is shown by the decrease of the mean RSD down to 28% in 2018. In contrast, the first large European interlaboratory comparison in 1999 showed a mean RSD of 51%.     

Europäische Dämmstoffnormen der 2. Generation: Prüfmethoden zur Ermittlung flüchtiger organischer Komponenten (VOC)

2nd generation European Standards for insulating materials and products: test methods for the determination of emissions of volatile organic compounds (VOC) In October 2001 ten “first generation” standards (EN 13162 through EN 13171) were introduced in Europe dealing with insulating materials and products. The new standards now in effect had to be based on the European Construction Products Directive (CPD) and conceptual details had been mandated by the European Commission to the standardization body CEN. Among other properties like thermal conductivity and fire performance the mandate requested to standardize a so called “initial type test (ITT)” for the release of dangerous substances (also called “regulated substances”) to be performed by an independent testing laboratory on behalf of the manufacturer before placing the product onto the market. However, due to the lack of experience and due to a non‐existing European harmonized common method for testing and classification, this property could not be included in the standards in due time and reference was only made to national regulations. Because of this shortcoming, a research project, started in 2003, developed a cost effective and very practical test method based on the emission cell device with a subunit that proved suitable for an initial type test (ITT) for the determination of emissions from thermal insulation materials and products – in particular volatile organic compounds (VOC).     

Simulation of VOC emissions from building materials by using the state-space method

There are many mass-transfer models for predicting VOC emissions from building materials described in the literature. In these models, the volatile organic compound (VOC) emission rate and its concentration in a chamber or a room are usually obtained by analytical method or numerical method. Although these methods demonstrate some salient features, they also have some flaws, e.g., for analytical method the solutions of both room or chamber VOC concentration and building material VOC emission rate are constituted of the sum of an infinite series, in which additional computation for finding roots to a transcendental function is necessary, but sometimes quite complicated. Besides, when it is applied in complex cases such as multilayer emission with internal reaction, the solution is very difficult to get; for conventional numerical methods such as finite difference method, discrete treatment of both time and space may cause calculation errors. Considering that, the state-space method widely used in modern automation control field and the heat transfer field is applied to simulate VOC emissions from building materials. It assumes that a slab of building material is composed of a number of finite layers, in each of which the instantaneous VOC concentration is homogenous during the entire process of emission, while the time is kept continuous. Based on this assumption we can predict both the VOC emissions rate and the concentrations of VOCs in the air of a chamber or room. The method is generally applied to simulate VOC emissions from arbitrary layers of building materials, and the solution is explicit and simple. What's more, the method can be applied to the cases where a reaction producing/removing VOC in building materials exists. For some specific cases the method is validated using the experimental data and the analytical solutions in the literature. The method provides a simple but powerful tool for simulating VOC emissions from building materials, which is especially useful in developing indoor air quality (IAQ) simulation software.     

装饰材料挥发性有机化合物研究现状与进展

综述了挥发性有机化合物（VOCs）定义域、危害和我国与国外限制法规的差异,分析了气态环境、液态和固态装饰材料中VOCs测试研究的技术现状并将固态材料中VOCs测试方法归纳为单体总量、静态释放量、动态释放量三类,指出了装饰材料VOCs研究发展方向和动态释放量的应用价值。     

Application of a novel reference material in an international round robin test on material emissions testing

Emission testing of products is currently a rapidly increasing field of measurement activity. Labeling procedures for construction products are based on such emission test chamber measurements, and hence, measurement performance should be verified. One possible route is to conduct testing of one material in different laboratories within a round robin test (RRT), ideally using homogeneous reference materials, which can be used within interlaboratory studies or as part of the quality management system to ensure comparable results. The applicability of a lacquer system with nine added VOCs (hexanal, styrene, n‐decane, limonene, 2‐ethyl‐1‐hexanol, N‐methyl‐α‐pyrrolidone, 2‐ethylhexyl acrylate, dimethyl phthalate, and n‐hexadecane) was evaluated in an international RRT with 55 participating laboratories. An intralaboratory quality check confirmed the homogeneity and reproducibility of the lacquer material for most of the compounds (RSD 5%‐6%), which was confirmed in the RRT. However, emissions varied for the polar compound N‐methyl‐α‐pyrrolidone and the higher boiling compounds 1,2‐dimethyl phthalate, and n‐hexadecane which could be traced back to analytical issues. In the RRT, the interlaboratory relative standard deviations (RSDs) ranged from 30% to 65% for all participants but for reference laboratories the range was between 20% and 45%.     

Emission of Volatile Organic Compounds from Furniture Coatings

Abstract Emissions of volatile organic compounds (VOC) from different types of furniture coatings have been investigated by test chamber studies under dynamic conditions. A total of 150 VOCs could be identified in the chamber air. Compound groups occurring most often were aliphatic and aromatic aldehydes, ketones, aromatic hydrocarbons, glycols and esters. Special attention was paid to the detection of typical components of coating materials such as acrylic monomers, photoinitiators and other additives. The TVOC-values, measured after a preconditioning period of 20 days, ranged from 4 μg/m³ to 1288 μg/m³ with an arithmetic mean of 173.9 μg/m³ and a median 60.0 μg/m³. The highest chamber concentrations of individual components were found for some solvent residues such as n-butylacetate, butylgly-col, 1-butanol-3-methoxy-acetate and butyldiglycolacetate. The results have shown that furniture may contribute significantly to indoor air pollution. The calculated emission factors were comparable with data reported for other indoor materials.con     

TVOC and formaldehyde emission behaviors from flooring materials bonded with environmental-friendly MF/PVAc hybrid resins

Polyvinyl acetate (PVAc) was added as a replacement for melamine-formaldehyde (MF) resin in the formaldehyde-based resin system to reduce formaldehyde and volatile organic compound (VOC) emissions from the adhesives used between plywoods and fancy veneers. A variety of techniques, including 20-l chamber, field and laboratory emission cell (FLEC), VOC analyzer and standard formaldehyde emission test (desiccator method), were used to determine the formaldehyde and VOC emissions from engineered flooring bonded with five different MF resin and PVAc blends at MF/PVAc ratios of 100:0, 70:30, 50:50, 30:70 and 0:100. Although urea-formaldehyde (UF) resin had the highest formaldehyde emission, the emission as determined by desiccator method was reduced by exchanging with MF resin. Furthermore, the formaldehyde emission level was decreased with increasing addition of PVAc as the replacement for MF resin. UF resin in the case of beech was over 5.0 mg/l, which exceeded E2 (1.5-5.0 mg/l) grade. However, MF30:PVAc70 was 相似文献   

Exchange of organic solvents between the atmosphere and grass--the use of open top chambers

Volatile organic compounds (VOC) are of increasing environmental significance as a result of continually increasing volumes of traffic on European roads. An open-top chamber fumigation system has been devised to investigate how these contaminants transfer between the atmosphere and the ground, and how they partition between and within air-plant-soil systems. Variation in chamber temperature, solar radiation in the chamber and chamber flow rate were identified as factors that affected final air concentrations. These were assessed and quantified for all individual chambers used--effectively characterising each chamber. The real-life VOC concentrations generated were stable and readily reproducible. Grass exposed to benzene, toluene, 1,1,1-trichloroethane and tetrachloroethene, respectively, equilibrated in response to a change in air concentration within hours. The rate of equilibration in exposed grass in all cases was independent of air temperature. 1,1,1-Trichloroethane and tetrachloroethene appear to be biologically inert demonstrating a simple physico-chemical approach to equilibrium, however, benzene and toluene do not appear independent of plant metabolic activity. Aqueous solubility can account for all of the toluene and benzene in the fumigated plant material.     

Comparison of selected volatile organic compounds during the summer and winter at urban sites in New Jersey

This paper presents a comparison of summer and winter levels of twenty-five selected volatile organic compounds (VOC) measured as part of the New Jersey project on Airborne Toxic Elements and Organic Substances (ATEOS). Most of the selected VOC were found in the range of 0.01–1.00 ppbv, with the exception of toluene (1–5 ppbv) and benzene (1–3 ppbv). However, peak levels of many compounds increased more than 100 fold during specific pollutant episodes. Generally, VOC levels were higher in the winter than the summer. Day to day variations of measured aromatic VOC showed significant correlations at each site suggesting an area source (motor vehicles), while there was little relationship between chlorinated species. During summer oxidant episodes, selected VOC increased from 2–10 times at Newark and Elizabeth, but not at Camden. In the winter, nocturnal temperature inversions caused levels of selected VOC to increase from 2–3 times seasonal average at all sites.     

A Study of Human Reactions to Emissions from Building Materials in Climate Chambers. Part II: VOC Measurements,Mouse Bioassay,and Decipol Evaluation in the 1–2 mg/m3 TVOC Range

Monitoring of human reactions to the emission of formaldehyde and volatile organic compounds (VOC) from four commonly used building materials was carried out. The building materials were: a painted gypsum board, a rubber floor, a nylon carpet, and a particle board with an acid-curing paint. The exposures were performed in climate chambers. The air quality was quantified on the decipol scale by a trained panel, measurements of formaldehyde and VOC being performed simultaneously. The irritating potency of the materials was measured by a mouse bioassay. The VOC measurements showed several malodorants and irritants. Some abundant VOC identified in the head-space analyses were absent in the climate chamber air. The rubber floor and the nylon carpet exhibited a marked increase in decipols compatible with a number of odorous VOC identified in the air. A high formaldehyde concentration (minimum 743μg/m³) was measured for the particle board coated with an acid-curing paint. This was not reflected by a corresponding relatively high decipol value but a long-lasting irritating potency was observed in the mouse bioassay. TVOC sampled on Tenax and expressed in mass per volume as well as in molar concentration, and decipol evaluation both have limitations and should be used with caution as indicators of (perceived) indoor air quality. Eye irritation expressed by means of the eye index reflecting the tear film quality index (comprised of break-up time, foam formation, thickness of the precorneal lipid layer of the tear film, and epithelial damage) was found to be insensitive to formaldehyde and a VOC mixture but sensitive to TVOC concentrations of 1–2 mg/m³. Lipophilic VOC may be the cause of reduced tear film quality by destabilization of the lipid multilayer of the tear film.     

Concentrations of Volatile Organic Compounds in Indoor Air – A Review

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.     

Assessment of the Health and Comfort Effects of Chemical Emissions from Building Materials: the State of the Art in the European Union*

Abstract The promotion of healthier indoor air requires the use of building materials whose chemical emissions are free of toxicity and unfavourable sensory properties. Testing and assessment of chemical emissions are essential in order to identify “safe” materials, and to encourage manufacturers to produce, and the market to adopt, such materials. Various testing and assessment procedures for building materials have been developed in European countries such as Germany, Denmark, Sweden, and Finland. Recently the European Collaborative Action “Indoor Air Quality and its Impact on Man” proposed criteria and a testing procedure for the assessment of VOC emissions from solid flooring materials. The innovative aspects of this proposal are: a procedure for the performance of chemical emissions testing; sensory testing coupled with toxicological evaluation; and a procedure to handle compounds for which toxicological information is scarce or absent. This procedure, after validation and experience from practical use, will probably be extended to other building materials.     

Small Chamber Tests and Headspace Analysis of Volatile Organic Compounds Emitted from Household Products

A chamber method for the characterization of the complex composition and time dependence of volatile organic compound (VOC) emissions from household products is described and the results obtained for five household products (two liquid floor detergents, one wax, a spray detergent for carpets, and a spray polish for furniture) are reported and compared to headspace measurements. An empirical mathematical model has been used to describe the time dependence of VOC concentrations in the chamber. The model allows characterization of complex emissions and their time dependence with relatively few parameters. Significant differences in the composition of emissions determined in the chamber and in headspace air have been observed and are discussed in terms of polarity and water solubility of the emitted compounds.     

Effect of bake-out on reducing VOC emissions and concentrations in a residential housing unit with a radiant floor heating system

This study analyzed the effect of bake-out on reducing VOC emissions and indoor concentrations in a residential housing unit with a radiant floor heating system. The effect of an elevated temperature on VOC emissions from a wallpaper assembly, plywood flooring assembly, and particle board (as an example of furniture material) was investigated in a small-scale chamber. Simultaneously, in the residential housing unit, we measured the VOC emissions from the materials and indoor concentrations in the housing unit that have previously undergone a bake-out procedure. The results from the small-scale chamber showed that VOC emissions from the investigated materials were clearly reduced by the elevated temperature. Other results from the residential housing unit showed that there were differences in the time for each material to reach the desired surface temperature, which resulted in different reduction ratio of VOC emissions and concentrations. The floor temperature increases the fastest. However, the furniture reached the desired temperature only after four days due to the large thermal mass of the particle board, which resulted in a relatively small reduction in the emissions. Our results indicate that bake-out period should be controlled for it to be effective in residential housing units that feature radiant flooring heating systems and a significant collection of furniture.     

Long-term Emission of Volatile Organic Compounds from Waterborne Paints – Methods of Comparison

The emission of volatile organic compounds (VOCs) from five different waterborne paints was measured in small climatic chambers under standard conditions over a one-year period. The aims of the study were to evaluate the time emission profiles and to develop methods for comparison of different paints. The paints were applied to tin-plated steel sheets. VOCs were sampled on Tenax TA and analysed by thermal desorption and gas chromatography. The chamber concentrations increased rapidly during the first few hours and then decreased as the emission rates dropped. A model expression including an exponentially decreasing emission rate of the paint film, the air exchange rate, and a normalization of the film thickness was fitted to the concentration versus time data. The time required to reach a given emission rate was estimated and found suitable for comparison of the emission of VOCs from the paints. It was found that data sampled within three weeks or less may be sufficient to predict the emission of VOCs up to one year. Reduction of long-term emissions may be achieved most efficiently by (1) substituting a more -volatile VOC whose emission is controlled by evaporation for a less volatile VOC characterized by diffusion-controlled emission and (2) reducing the paint film thickness rather than reducing the initial VOC content of the paint.     

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.     

The Influence of Temperature on the Emission of Volatile Organic Compounds from PVC flooring,Carpet, and Paint

Abstract The influence of temperature on the emission rate of volatile organic compounds (VOC) from four indoor materials was investigated in a small dynamic test chamber. The materials investigated were two carpets, a PVC flooring and a paint; the temperature range investigated was 23–50°C. The general trend was an increased initial emission rate and an increased decay rate with increasing temperature. The total emitted mass from paint is independent of temperature which means that bake-out is expected to be successful. The total emitted mass of the carpets and the PVC flooring increased with temperature, which suggests an influence of chemical reactions. In these cases, bake-out periods of a few days may be unsuccessful and the exposure of the population may be underestimated when using data from experiments performed at the (lower) standard temperature.     

Simultaneous estimation of VOCs diffusion and partition coefficients in building materials via inverse analysis

An analytic model describing the one-dimensional transient VOC diffusion in the building material slab was selected. An inverse analysis was applied to estimate the volatile organic compounds (VOCs) constant diffusion coefficient (D) and partition coefficient (K) in the building material. The present parameter estimation problem was solved with Levenberg–Marquardt's method of minimization of the ordinary least-squares norm. The effects of the number and the time step of measurements, errors involved in the initial concentration data in the building material, random errors involved in the measured VOCs concentration data in the chamber air and errors involved in the calculation of the mean convective mass transfer coefficient on the accuracy of estimates were studied. The first two factors were found to have significant effects on the accuracy of the estimates, while the effect of the third factor was insignificant. The results also indicate that D is insensitive to the errors involved in the mean convective mass transfer coefficient. The present study would be useful for obtaining material properties and helpful for designing and improving experiments.     

Multi-target identification for emission parameters of building materials by unsteady concentration measurement in airtight micro-cell-type chamber

The purpose of this study is to develop a concurrent determination method that can estimate multiple emission parameters, that is, the emission rate, initial concentration and effective diffusion coefficient Dc in building materials, by a single unsteady concentration measurement. This study focused on the time history of VOC concentration in the gas phase that occurred when the target building material was covered with an airtight micro-cell. The VOC concentration in the micro-cell gradually increased and finally reached an equilibrium concentration. Under the condition of uniform distribution of initial concentration, the profile of VOC concentration in the micro-cell was determined by the order of the Dc value. A chart of the time history of VOC concentration as a function of Dc and thickness of building materials was prepared in advance by numerical analysis and then Dc was estimated by overlapping the measurement result with this chart. A chart of emission rate as a function of Dc and building material thickness was also prepared and the determination procedure of the emission rate taking into account the consistency between the 20 L small chamber method with in- and out-flow and the micro-cell method under an airtight condition was proposed. The estimation results of Dc and emission rate by this method were reasonably consistent with the results of the conventional method.     

The effects of paints and moisture content on the indoor air emissions from pinewood (Pinus sylvestris) boards

The emissions of volatile organic compounds (VOCs) from building materials may significantly contribute to indoor air pollution, and VOCs have been associated with odor annoyance and adverse health effects. Wood materials together with coatings are commonly used indoors for furniture and large surfaces such as walls, floors, and ceilings. This leads to high surface-to-volume ratios, and therefore, these materials may participate remarkably to the VOC levels of indoor environment. We studied emissions of VOCs and carbonyl compounds from pinewood (Pinus sylvestris) boards of 10% and 16% moisture contents (MC) with three paints using small-scale test chambers (27 L). The emissions from uncoated pinewood and paints (on a glass substrate) were tested as references. The 28-day experiment showed that the VOC emissions from uncoated pinewood were lower from sample with 16% MC. Painted pinewood samples showed lower emissions compared to paints on glass substrate. Additionally, paints on 16% MC pinewood exhibited lower emissions than on drier 10% MC wood. The emissions from painted pinewood samples were dominated by paint-based compounds, but the share of wood-based compounds increased over time. However, we noticed differences between the paints, and wood-based emissions were clearly higher with the most permeable paint.