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Liu N, Zhang X, Wang L, Liang K, Zhang Y, Cao J. Early-Stage Emissions of Formaldehyde and Volatile Organic Compounds from Building Materials: Model Development, Evaluation, and Applications. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:14680-14689. [PMID: 36112514 DOI: 10.1021/acs.est.2c04572] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Emissions of formaldehyde and volatile organic compounds (VOCs) from building materials may result in poor indoor air quality. The emission process can be divided into three stages over time: early, transition, and equilibrium stages. In existing studies, mass transfer models without distinguishing the early and transition stages have been widely used for characterizing the formaldehyde/VOC emissions, with three key parameters involved in these models. Many methods have been proposed for determining these parameters by fitting the corresponding models to experimental data. However, multiple groups of best-fit parameters might coexist if experimental data are obtained at the early stage (to shorten the experimental time). Therefore, we developed a novel mass transfer model to describe the early-stage emissions by assuming the building material as semi-infinite medium. The novel model indicated that the early-stage emission was governed by only two parameters, instead of three parameters, which explained the reason for the multi-solution problem of existing methods. Subsequently, the application condition of the early-stage model was clarified, showing that the early stage was very common in the emissions of formaldehyde/VOCs. Finally, a novel approach for characterizing the emissions of formaldehyde/VOCs from building materials was proposed to eliminate the negative effects of the multi-solution problem.
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Affiliation(s)
- Ningrui Liu
- Department of Building Science, Tsinghua University, Beijing 100084, China
- Beijing Key Laboratory of Indoor Air Quality Evaluation and Control, Beijing 100084, China
| | - Xu Zhang
- Department of Building Science, Tsinghua University, Beijing 100084, China
- Beijing Key Laboratory of Indoor Air Quality Evaluation and Control, Beijing 100084, China
| | - Luyang Wang
- Department of Building Science, Tsinghua University, Beijing 100084, China
- Beijing Key Laboratory of Indoor Air Quality Evaluation and Control, Beijing 100084, China
| | - Kai Liang
- Department of Building Science, Tsinghua University, Beijing 100084, China
- Beijing Key Laboratory of Indoor Air Quality Evaluation and Control, Beijing 100084, China
| | - Yinping Zhang
- Department of Building Science, Tsinghua University, Beijing 100084, China
- Beijing Key Laboratory of Indoor Air Quality Evaluation and Control, Beijing 100084, China
| | - Jianping Cao
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510006, China
- Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Guangzhou 510006, China
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Cao J, Xie S, Cheng Z, Li R, Xu Y, Huang H. Impacts of sampling-tube loss on quantitative analysis of gaseous semi-volatile organic compounds (SVOCs) using an SPME-based active sampler. CHEMOSPHERE 2022; 301:134780. [PMID: 35500633 DOI: 10.1016/j.chemosphere.2022.134780] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2021] [Revised: 01/19/2022] [Accepted: 04/26/2022] [Indexed: 06/14/2023]
Abstract
Active samplers are widely used in the quantification of gaseous semi-volatile organic compounds (SVOCs). A sampling tube is often assembled upstream of the sampler, especially in the active samplers used for separating the particle-phase and gas-phase SVOCs and in the newly-designed active sampler based on solid-phase microextraction (SPME). However, gaseous SVOCs can be easily adsorbed by the sampling tube, which may induce significant errors to the quantitative results. Taking the SPME-based active sampler as an example, a mass-transfer model was developed to characterize the sampling-tube loss of gaseous SVOCs. Experiments involving six SVOCs were conducted. The model predictions (with a best-fit surface/air partition coefficient of SVOCs) were found to be consistent with the measurements. Both model predictions and experimental data indicated that the measured concentrations were significantly lower than the actual concentration (around 60% lower) due to the sampling-tube loss. The duration of sampling-tube loss (τe, minutes to days) varied with the volatility of SVOCs (vapor pressure, Vp), i.e., log τe linearly increased as increasing log Vp. The relationship could be helpful for determining the sampling strategies to eliminate (reduce) the effects of sampling-tube loss according to the volatility of SVOCs. The above conclusions may be also applicable for other active samplers of gaseous SVOCs. However, further studies are required to quantify the effects of sampling-tube loss for other active samplers due to the difference in the size and shape of the sampling tube between them and the SPME-based active sampler. The corresponding mass-transfer model and experimental procedure may require adjustment as appropriate.
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Affiliation(s)
- Jianping Cao
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou, 510006, China; Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Guangzhou, 510006, China
| | - Siqi Xie
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou, 510006, China
| | - Zhibin Cheng
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou, 510006, China
| | - Runze Li
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou, 510006, China
| | - Ying Xu
- Department of Building Science, Tsinghua University, Beijing, 100084, China
| | - Haibao Huang
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou, 510006, China; Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Guangzhou, 510006, China.
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Salim F, Górecki T. Theory and modelling approaches to passive sampling. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2019; 21:1618-1641. [PMID: 31528928 DOI: 10.1039/c9em00215d] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Designs and applications of passive samplers for various environmental compartments have been broadened significantly since their introduction. Understanding the theory behind passive sampling is essential for proper development of sampling methods and for accurate interpretation of the results. Theoretical underpinnings of passive sampling have been explored using different approaches. The aim of this review is to describe passive sampling theory and modelling approaches presented in the literature in a manner that allows researchers to obtain comprehensive understanding of them and to recognize the assumptions behind each approach together with their applicability to a given passive sampling technique. A common approach originates from Whitman's two-film theory and produces an exponential model that describes the entire passive sampling process. This approach, however, is based on several assumptions including linear exchange kinetics between the sampled medium and the passive sampler. Two-phase air passive samplers with a well-defined barrier are commonly modeled based on the zero-sink assumption, which assumes efficient trapping of analytes in the receiving phase. This assumption may become invalid under various scenarios; consequently, other approaches to modelling have been introduced including simulation of the sampling process by approximate temporal-steady states in hypothetical segments in the adsorption phase. Another approach uses dynamic models to determine accumulation of analytes in passive samplers. Dynamic models are capable of describing mass accumulation in the passive sampler, its transient response, and its response to fluctuations in environmental concentrations. Finally, empirically calibrated models, attempting to simplify the process of passive sampling rate determination, are also presented. In general, dynamic models are used to establish a profound understanding of the sampling process and analyse the applicability of the simpler models and their assumptions, while the simplified models are desirable and practical for most users. Nonetheless, due to the advancement in the computational tools, application of the dynamic models could be made simple and user-friendly.
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Affiliation(s)
- Faten Salim
- University of Waterloo, Department of Chemistry, 200 University Avenue West, Waterloo, ON, Canada N2L 3G1.
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Salim F, Ioannidis M, Penlidis A, Górecki T. Modelling permeation passive sampling: intra-particle resistance to mass transfer and comprehensive sensitivity analysis. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2019; 21:469-484. [PMID: 30724928 DOI: 10.1039/c8em00565f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
A mathematical model developed previously to describe the sampling process in permeation passive samplers with non-porous adsorbents and evaluated using the Waterloo Membrane Sampler (WMS) is here extended to include adsorbents with porous particles. This work was motivated by the need to expand the model applicability to include the various types of adsorbents used in the WMS, and to develop a deep understanding of the model sensitivity towards required parameters. The effects of intraparticle porosity on the effective diffusivity of the analyte in a bed of porous particles and on the mass transfer coefficient for analyte transport from the interparticle void phase to the porous solid phase are both evaluated. Experimental validation of the applicability of the model on adsorbents with microporous particles was carried out using the WMS containing Anasorb 747, a carbon-based adsorbent with highly porous particles. Good agreement between the experimental and model results was found. A comprehensive sensitivity analysis was also conducted to identify the parameters with the greatest influence on the results of the calculated uptake rate. This analysis included two types of adsorbents with different sorption strengths. The results showed that the uptake rate sensitivity is limited to parameters related to mass transfer in the membrane for strong adsorbents. On the other hand, sensitivity to parameters related to mass transfer in the sorbent bed becomes more significant as the strength of the adsorbent decreases; however, this effect can be reduced by increasing the membrane thickness. Influential parameters in the sorbent bed are also affected by the temperature. Nevertheless, the contribution of this change to the total effect of temperature change on the uptake rate is expected to be negligible within the small range of temperature variations usually encountered during a single environmental sampling event, especially in soil-gas sampling which is the most widely used application of the WMS.
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Affiliation(s)
- Faten Salim
- University of Waterloo, Department of Chemistry, 200 University Avenue West, Waterloo, ON, Canada N2L 3G1.
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Healy RM, Bennett J, Wang JM, Karellas NS, Wong C, Todd A, Sofowote U, Su Y, Di Federico L, Munoz A, Charland JP, Herod D, Siu M, White L. Evaluation of a Passive Sampling Method for Long-Term Continuous Monitoring of Volatile Organic Compounds in Urban Environments. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:10580-10589. [PMID: 30119604 DOI: 10.1021/acs.est.8b02792] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Environmental Protection Agency Method 325 was developed for continuous passive monitoring of volatile organic compounds (VOCs), particularly benzene, at petroleum refinery fencelines. In this work, a modified version of the method was evaluated at an Ontario near-road research station in winter to assess its suitability for urban air quality monitoring. Samples were collected at 24 hour and 14 day resolution to investigate accuracy for different exposure times. Tubes were analyzed by thermal desorption-gas chromatography-mass spectrometry, and 11 VOCs were quantified, including aromatic air toxics. The same VOCs were simultaneously monitored using traditional canister sampling for comparison, and a subset of four were also monitored using a novel miniature gas chromatograph. Good agreement (within 10%) was observed between the 14 day passive tube samples and the canister samples for benzene. However, field-calibrated uptake rates were required to correct passive tube concentrations for less volatile aromatics. Passive tube deployment and analysis is inexpensive; sampling does not require power, and accurate measurements of benzene are demonstrated here for an urban environment. The method is expected to be advantageous for the generation of long-term continuous benzene datasets suitable for epidemiological research with greater spatial coverage than is currently available using traditional monitoring techniques.
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Affiliation(s)
- Robert M Healy
- Environmental Monitoring and Reporting Branch , Ontario Ministry of the Environment, Conservation and Parks , Toronto , Ontario M9P 3V6 , Canada
| | - Julie Bennett
- Environmental Monitoring and Reporting Branch , Ontario Ministry of the Environment, Conservation and Parks , Toronto , Ontario M9P 3V6 , Canada
| | - Jonathan M Wang
- Environmental Monitoring and Reporting Branch , Ontario Ministry of the Environment, Conservation and Parks , Toronto , Ontario M9P 3V6 , Canada
| | - Nicholas S Karellas
- Environmental Monitoring and Reporting Branch , Ontario Ministry of the Environment, Conservation and Parks , Toronto , Ontario M9P 3V6 , Canada
| | - Colman Wong
- Environmental Monitoring and Reporting Branch , Ontario Ministry of the Environment, Conservation and Parks , Toronto , Ontario M9P 3V6 , Canada
| | - Aaron Todd
- Environmental Monitoring and Reporting Branch , Ontario Ministry of the Environment, Conservation and Parks , Toronto , Ontario M9P 3V6 , Canada
| | - Uwayemi Sofowote
- Environmental Monitoring and Reporting Branch , Ontario Ministry of the Environment, Conservation and Parks , Toronto , Ontario M9P 3V6 , Canada
| | - Yushan Su
- Environmental Monitoring and Reporting Branch , Ontario Ministry of the Environment, Conservation and Parks , Toronto , Ontario M9P 3V6 , Canada
| | - Linda Di Federico
- Environmental Monitoring and Reporting Branch , Ontario Ministry of the Environment, Conservation and Parks , Toronto , Ontario M9P 3V6 , Canada
| | - Anthony Munoz
- Environmental Monitoring and Reporting Branch , Ontario Ministry of the Environment, Conservation and Parks , Toronto , Ontario M9P 3V6 , Canada
| | - Jean-Pierre Charland
- Air Quality Research Division , Environment and Climate Change Canada , Ottawa , Ontario K4M 1B4 , Canada
| | - Dennis Herod
- Air Quality Research Division , Environment and Climate Change Canada , Ottawa , Ontario K4M 1B4 , Canada
| | - May Siu
- Air Quality Research Division , Environment and Climate Change Canada , Ottawa , Ontario K4M 1B4 , Canada
| | - Luc White
- Air Quality Research Division , Environment and Climate Change Canada , Ottawa , Ontario K4M 1B4 , Canada
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Salim F, Ioannidis M, Górecki T. Experimentally validated mathematical model of analyte uptake by permeation passive samplers. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2017; 19:1363-1373. [PMID: 28937162 DOI: 10.1039/c7em00315c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
A mathematical model describing the sampling process in a permeation-based passive sampler was developed and evaluated numerically. The model was applied to the Waterloo Membrane Sampler (WMS), which employs a polydimethylsiloxane (PDMS) membrane as a permeation barrier, and an adsorbent as a receiving phase. Samplers of this kind are used for sampling volatile organic compounds (VOC) from air and soil gas. The model predicts the spatio-temporal variation of sorbed and free analyte concentrations within the sampler components (membrane, sorbent bed and dead volume), from which the uptake rate throughout the sampling process can be determined. A gradual decline in the uptake rate during the sampling process is predicted, which is more pronounced when sampling higher concentrations. Decline of the uptake rate can be attributed to diminishing analyte concentration gradient within the membrane, which results from resistance to mass transfer and the development of analyte concentration gradients within the sorbent bed. The effects of changing the sampler component dimensions on the rate of this decline in the uptake rate can be predicted from the model. Performance of the model was evaluated experimentally for sampling of toluene vapors under controlled conditions. The model predictions proved close to the experimental values. The model provides a valuable tool to predict changes in the uptake rate during sampling, to assign suitable exposure times at different analyte concentration levels, and to optimize the dimensions of the sampler in a manner that minimizes these changes during the sampling period.
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Affiliation(s)
- F Salim
- University of Waterloo, Department of Chemistry, 200 University Avenue West, Waterloo, ON, Canada N2L 3G1.
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Cao J, Liu N, Zhang Y. SPME-Based C a-History Method for Measuring SVOC Diffusion Coefficients in Clothing Material. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:9137-9145. [PMID: 28714305 DOI: 10.1021/acs.est.7b02540] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Clothes play an important role in dermal exposure to indoor semivolatile organic compounds (SVOCs). The diffusion coefficient of SVOCs in clothing material (Dm) is essential for estimating SVOC sorption by clothing material and subsequent dermal exposure to SVOCs. However, few studies have reported the measured Dm for clothing materials. In this paper, we present the solid-phase microextraction (SPME) based Ca-history method. To the best of our knowledge, this is the first try to measure Dm with known relative standard deviation (RSD). A thin sealed chamber is formed by a circular ring and two pieces of flat SVOC source materials that are tightly covered by the targeted clothing materials. Dm is obtained by applying an SVOC mass transfer model in the chamber to the history of gas-phase SVOC concentrations (Ca) in the chamber measured by SPME. Dm's of three SVOCs, di-iso-butyl phthalate (DiBP), di-n-butyl phthalate (DnBP), and tris(1-chloro-2-propyl) phosphate (TCPP), in a cotton T-shirt can be obtained within 16 days, with RSD less than 3%. This study should prove useful for measuring SVOC Dm in various sink materials. Further studies are expected to facilitate application of this method and investigate the effects of temperature, relative humidity, and clothing material on Dm.
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Affiliation(s)
- Jianping Cao
- Department of Building Science, Tsinghua University , Beijing 100084, China
- Beijing Key Laboratory of Indoor Air Quality Evaluation and Control , Beijing 100084, China
| | - Ningrui Liu
- Department of Building Science, Tsinghua University , Beijing 100084, China
- Beijing Key Laboratory of Indoor Air Quality Evaluation and Control , Beijing 100084, China
| | - Yinping Zhang
- Department of Building Science, Tsinghua University , Beijing 100084, China
- Beijing Key Laboratory of Indoor Air Quality Evaluation and Control , Beijing 100084, China
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Sakai N, Yamamoto S, Matsui Y, Khan MF, Latif MT, Ali Mohd M, Yoneda M. Characterization and source profiling of volatile organic compounds in indoor air of private residences in Selangor State, Malaysia. THE SCIENCE OF THE TOTAL ENVIRONMENT 2017; 586:1279-1286. [PMID: 28236484 DOI: 10.1016/j.scitotenv.2017.02.139] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Revised: 02/16/2017] [Accepted: 02/17/2017] [Indexed: 06/06/2023]
Abstract
Volatile Organic Compounds (VOCs) in indoor air were investigated at 39 private residences in Selangor State, Malaysia to characterize the indoor air quality and to identify pollution sources. Twenty-two VOCs including isomers (14 aldehydes, 5 aromatic hydrocarbons, acetone, trichloroethylene and tetrachloroethylene) were collected by 2 passive samplers for 24h and quantitated using high performance liquid chromatography and gas chromatography mass spectrometry. Source profiling based on benzene/toluene ratio as well as statistical analysis (cluster analysis, bivariate correlation analysis and principal component analysis) was performed to identify pollution sources of the detected VOCs. The VOCs concentrations were compared with regulatory limits of air quality guidelines in WHO/EU, the US, Canada and Japan to clarify the potential health risks to the residents. The 39 residences were classified into 2 groups and 2 ungrouped residences based on the dendrogram in the cluster analysis. Group 1 (n=30) had mainly toluene (6.87±2.19μg/m3), formaldehyde (16.0±10.1μg/m3), acetaldehyde (5.35±4.57μg/m3) and acetone (11.1±5.95μg/m3) at background levels. Group 2 (n=7) had significantly high values of formaldehyde (99.3±10.7μg/m3) and acetone (35.8±12.6μg/m3), and a tendency to have higher values of acetaldehyde (23.7±13.5μg/m3), butyraldehyde (3.35±0.41μg/m3) and isovaleraldehyde (2.30±0.39μg/m3). The 2 ungrouped residences showed particularly high concentrations of BTX (benzene, toluene and xylene: 235μg/m3 in total) or acetone (133μg/m3). The geometric mean value of formaldehyde (19.2μg/m3) exceeded an 8-hour regulatory limit in Canada (9μg/m3), while those in other compounds did not exceed any regulatory limits, although a few residences exceeded at least one regulatory limit of benzene or acetaldehyde. Thus, the VOCs in the private residences were effectively characterized from the limited number of monitoring, and the potential health risks of the VOCs exposure, particularly formaldehyde, should be considered in the study area.
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Affiliation(s)
- Nobumitsu Sakai
- Division of Environmental Engineering, Graduate School of Engineering, Kyoto University, Kyoto 6158540, Japan; Shimadzu-UMMC Centre of Xenobiotic Studies, Department of Pharmacology, Faculty of Medicine, University of Malaya, Kuala Lumpur 50603, Malaysia.
| | - Shuta Yamamoto
- Division of Environmental Engineering, Graduate School of Engineering, Kyoto University, Kyoto 6158540, Japan
| | - Yasuto Matsui
- Division of Environmental Engineering, Graduate School of Engineering, Kyoto University, Kyoto 6158540, Japan
| | - Md Firoz Khan
- Research Centre for Tropical Climate Change System (IKLIM), Institute of Climate Change, Universiti Kebangsaan Malaysia, Bangi, Selangor 43600, Malaysia
| | - Mohd Talib Latif
- School of Environment and Natural Resource Sciences, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi, Selangor 43600, Malaysia; Institute for Environment and Development (LESTARI), Universiti Kebangsaan Malaysia, Bangi, Selangor 43600, Malaysia
| | - Mustafa Ali Mohd
- Shimadzu-UMMC Centre of Xenobiotic Studies, Department of Pharmacology, Faculty of Medicine, University of Malaya, Kuala Lumpur 50603, Malaysia
| | - Minoru Yoneda
- Division of Environmental Engineering, Graduate School of Engineering, Kyoto University, Kyoto 6158540, Japan
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