Determination of material emission signatures by PTR-MS and their correlations with odor assessments by human subjects (original) (raw)
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Atmospheric Environment, 1999
The emissions from five commonly used building products were studied in small-scale test chambers over a period of 50 days. The odor intensity was assessed by a sensory panel and the concentrations of selected volatile organic compounds (VOCs) of concern for the indoor air quality were measured. The building products were three floor coverings: PVC, floor varnish on beechwood parquet and nylon carpet on a latex foam backing; an acrylic sealant, and a waterborne wall paint on gypsum board. The impacts of the VOC concentration in the air and the air velocity over the building products on the odor intensity and on the emission rate of VOCs were studied. The emission from each building product was studied under two or three different area-specific ventilation rates, i.e. different ratios of ventilation rate of the test chamber and building product area in the test chamber. The air velocity over the building product samples was adjusted to different levels between 0.1 and 0.3 m s\. The origin of the emitted VOCs was assessed in order to distinguish between primary and secondary emissions. The results show that it is reasonable after an initial period of up to 14 days to consider the emission rate of VOCs of primary origin from most building products as being independent of the concentration and of the air velocity. However, if the building product surface is sensitive to oxidative degradation, increased air velocity may result in increased secondary emissions. The odor intensity of the emissions from the building products only decayed modestly over time. Consequently, it is recommended to use building products which have a low impact on the perceived air quality from the moment they are applied. The odor indices (i.e. concentration divided by odor threshold) of primary VOCs decayed markedly faster than the corresponding odor intensities. This indicates that the secondary emissions rather than the primary emissions, are likely to affect the perceived air quality in the long run. Some of the building products continued to affect the perceived air quality despite the concentrations of the selected VOCs resulted in odor indices less than 0.1. Therefore, odor indices less than 0.1 as an accept criterion cannot guarantee that a building product has no impact on the perceived air quality.
Building occupants are exposed to complex mixtures of air pollutants including many volatile organic compounds (VOCs). A recent review summarized the central tendency and upper limit indoor VOC concentrations measured in North American residences and office buildings since 1990. Although this database is limited in many respects, it serves as a useful starting point for evaluating the potential health and comfort effects of indoor VOC exposures. Excluding cancer and birth defects, the primary concern is chronic inhalation exposure to toxicants that can cause serious health problems. Additionally, building occupants react to the quality of indoor air through their sensory perceptions and frequently experience unpleasant odors and irritation of the eyes and upper respiratory tract. In this paper, we conduct a simple screening-level assessment of indoor VOC concentrations. We compare measured VOC concentrations to published odor thresholds, sensory irritation levels derived for the general population, and noncancer chronic health guidelines. Hazard quotients are individually calculated for these three effects by dividing maximum or derived 95th percentile VOC concentrations by our selected best estimates of guidance levels for the general population. These results provide a basis for broadly classifying commonly encountered VOCs into groups according to the likelihood that they will produce effects among building occupants. This methodology shows that only a small number of the more than 100 reported VOCs exceed levels that are likely to be of concern with respect to the health and comfort endpoints considered. Although data is lacking for a number of odorous compounds potentially present in buildings, the results indicate that carboxylic acids, higher molecular weight aldehydes and less volatile aromatic hydrocarbons are most likely to be perceived by olfaction and that there is more probability of detection in residences than in offices. Sensory irritation levels were approached or exceed by only a very small number of relatively potent, reactive VOCs. Of these, acrolein was by far the most potent irritant. Although more detailed consideration of the underlying toxicological data is needed, the results suggest that only a small number of commonly measured VOCs, when considered singly, are likely to produce serious irreversible health effects not associated with cancer. These compounds include lower molecular weight aldehydes, and several aromatic hydrocarbons. Again, acrolein stands out as the most potent compound. Based on these results, we recommend that studies to characterize indoor VOC concentrations and exposures focus their resources on compounds that are most likely to impact occupants as determined by the study objectives. For a very few compounds, such as acrolein and formaldehyde, the evidence based on sensory irritation and chronic toxicity appears sufficient to warrant efforts to reduce and control sources of these compounds in buildings.
2009
The objectives of the present work were to examine the relationships between sensory assessments of air quality made using different methods: odor intensity by category scale, category-ratio scale and equal-intensity matching with acetone as a reference and acceptability scale, and to study whether the assessments of acceptability can be explained by selected characteristics of the air. A sensory panel assessed the air polluted by emissions from different building materials at different area-specific ventilation rates. The three assessments of odor intensity were linearly strongly correlated with each other. Therefore, for practical applications it seems feasible to apply only one of the investigated methods. Odor intensity was strongly correlated with the assessments of acceptability of the air. This suggests that, for the investigated materials, the assessments of acceptability are mainly influenced by odor intensity. The selected descriptors characterizing the air could not explain the assessments of acceptability because the odor intensity levels were generally low.
Odour assessment as a necessary complement to chemical evaluation of building products
Evaluation of emissions from building products is mainly focused on comparison between exposition concentrations of identified individual organic compounds and health criteria. No adequate integrated criterion is available for interaction and mixture effects. Besides, everyone performs daily evaluation of perceived air quality. Human beings through their senses, for example, olfaction and chemesthesis, are able to achieve a synthetic response to a global mixture of compounds. It is thus essential to perform sensory tests complementing chemical analysis to take into account the impact of the whole emission of sources. Two related questions remain to be answered: the kind of sensory test and the type of sensory information and criterion to be used in the evaluation procedure.
Science of The Total Environment, 1999
. The primary emissions of VOCs e.g. solvents from building products influence the perceived indoor air quality Ž during the initial decay period. However, secondary emissions will continue thereafter chemical or physical . degradation, e.g. oxidation, hydrolysis, mechanical wear, maintenance , in addition to sorption processes. Emission testing for primary VOC emissions is necessary, but insufficient to characterise the impact of building products in their entire life span on the perceived air quality. Methods to distinguish between the two types of emissions are required. Also, the influence of climate parameters on the emission rates is necessary to know for proper testing. Future product development and selection strategies of new building products should consider the secondary emissions, in addition to the contribution from the use of auxiliary agents for cleaning, maintenance, and other potential impacts either physical or chemical in nature. Some of the requirements for emission testing are discussed in terms of secondary vs. primary emissions in order to develop 'healthierrbetter' building products for the indoor environment. In addition, some of the assumptions about the possible impact of VOCs on health and comfort in the indoor environment are presented. Odour thresholds for VOCs are one or more orders of magnitude lower than the corresponding airway irritation estimates, and it also appears that chemically non-reactive VOCs are not sufficiently strong irritants to cause airway irritation at concentrations normally encountered indoors. Finally, future requirements for analytical laboratory performances is proposed to accommodate the increasing need to establish which VOCs may be responsible for the perception of odour intensity from building products. ᮊ 0048-9697r99r$ -see front matter ᮊ 1999 Elsevier Science B.V. All rights reserved. Ž . PII: S 0 0 4 8 -9 6 9 7 9 9 0 0 0 1 9 -4 ( ) P. Wolkoff r The Science of the Total En¨ironment 227 1999 197᎐213 198 ( ) ( ) P. Wolkoff r The Science of the Total En¨ironment 227 1999 197᎐213 201
Knowing the value of the key mass-transfer model parameters is a critical requirement for evaluating volatile organic compound (VOC) emissions from indoor materials. The key parameters are diffusion coefficient (D), partition coefficient (K), and initial material-phase emittable concentration (C0). Although these parameters can be individually measured in the laboratory, the required time and expense are substantial. A simple method of determining D and C0 using data from ventilated chamber tests and dimensionless analysis is proposed and then validated using VOC emission data from the material emissions database developed by National Research Council Canada (NRC). The primary application of this method is to provide a rapid screening-level estimate of inhalation exposure to VOCs in building materials. Two standard scenarios using the NRC database are employed to demonstrate the value of the approach to indoor air quality assessment. The method could be a useful screening tool for assessing material emissions or environmental exposures.
Indoor Air Quality Assessment: Review on the topic of VOCs
Volatile Organic Compounds (VOCs) are toxic chemicals harmful for the environmental sustainability and human health. Due to the several types of VOCs and the diversity in their physico-chemical properties, it is difficult to develop standard methods for sampling and analysis. The majority of methods depend on the compounds of interest and the required duration of sampling. Each method is associated with a certain value of specificity and sensitivity. To date, however, no specific method qualifies as being the most accurate. This review reports the most common methods employed in determination of VOCs, based on the international literature.
Journal of Physical Chemistry & Biophysics, 2014
ABSTRACT Volatile Organic Compounds (VOCs) are toxic chemicals harmful for the environmental sustainability and human health. Due to the several types of VOCs and the diversity in their physico-chemical properties, it is difficult to develop standard methods for sampling and analysis. The majority of methods depend on the compounds of interest and the required duration of sampling. Each method is associated with a certain value of specificity and sensitivity. To date, however, no specific method qualifies as being the most accurate. This review reports the most common methods employed in determination of VOCs, based on the international literature.
Determination of VOCs in the Indoor Air of a New and a Renovated Apartment
Selected Scientific Papers - Journal of Civil Engineering, 2016
This study deals with the occurrence of volatile organic compounds (VOCs) in the indoor environment of a new and a renovated apartment. Qualitative determination of VOCs was carried out with a gas chromatograph with surface acoustic wave detector (GC/SAW). Concentrations of total volatile organic compounds (TVOC) were determined by a photoionization detector with UV lamp. Simultaneously, temperature and relative humidity were monitored with a data logger. The aim of this study was to determine of TVOC concentrations, to use of GC/SAW for determination of individual VOCs in indoor air as well as to predict possible sources of VOCs in these apartments. Measurements were performed after each construction work for better resolution of the contributions of individual materials to the levels of VOC. Mean concentrations of TVOC were 624 μg/m3 in the renovated apartment and 1,686 μg/m3 in the new apartment after completion of all works. The results from the renovated apartment showed that t...
A comprehensive VOC emission database for commonly-used building materials
2003
A material emission database was developed for 48 building materials based on ASTM test methods. The database consists of model coefficients for the five to six most abundant volatile organic compounds (VOCs) emitted from each building material. A power-law model was used to describe the emissions from dry materials including particleboard, plywood, oriented strand board (OSB), solid wood, gypsum wallboard, acoustic ceiling tile, vinyl flooring, underpad, and carpet. The VOC emissions from wet materials were divided into three temporal regions with separate emission models including a vapor pressure and boundary layer model, an exponential decay model, and a power-law model. The wet materials include wood stain, polyurethane varnish, adhesive, caulking sealant, floor wax, and paint. Since the database is linked to a single-zone indoor air quality simulation program, it can be used to explore trade-offs between material selection and ventilation strategies.