Jiping Zhu - Academia.edu (original) (raw)
Papers by Jiping Zhu
Journal of Hazardous Materials, Dec 1, 2013
h i g h l i g h t s • 2,2 ,4,4-Tetrabromodiphenyl ether (BDE-47) was found transformed to six les... more h i g h l i g h t s • 2,2 ,4,4-Tetrabromodiphenyl ether (BDE-47) was found transformed to six less brominated BDE analogs under UV irradiation. • BDE-47 was found degraded faster in liquid phase than in gas phase. • Two brominated phenols were formed in the transformation of BDE-47 in gas phase. • The bromine on the ortho positions of the phenyl rings was found lost first to form 2,4,4-tribromodiphenyl ether (BDE-28). • The more volatile less brominated BDEs are a source of secondary pollutants in the environment.
Chemosphere, Dec 1, 1999
A method for estimating VOC emission rates from hydrocarbon solvent-based indoor materials has be... more A method for estimating VOC emission rates from hydrocarbon solvent-based indoor materials has been developed. The estimation is based on the assumption that the emission rate of individual VOCs is proportional to its molar fraction in the evaporative mixture at the time, its saturated pure vapor pressure and total remaining VOCs in the material. The paper demonstrates, through three hydrocarbon solvent-based polyurethane surface coating materials, a practical way to calculate these three parameters using chemical composition analysis results. The estimated total VOC emission rates were in good agreement with the results of weight loss experiments.
Building and Environment, Jul 1, 2015
This study investigated phthalate emissions from vinyl flooring in a large-scale chamber. Vinyl f... more This study investigated phthalate emissions from vinyl flooring in a large-scale chamber. Vinyl flooring materials were examined for their phthalates content; one with high contents of diisononyl phthalate (DINP) and di(2-ethylhexyl) phthalate (DEHP) was selected for emissions testing in a small chamber at two different temperatures. Using the same type of vinyl flooring, large-scale chamber experiments were then conducted in three testing phases. In the first phase, the gas-phase concentrations of DINP and DEHP in the large chamber at 36 C were about three times lower than those in the small chamber under the same temperature, which is consistent with its lower area/volume ratio. In the second phase, when a large air mixing fan inside the chamber was replaced with a small fan, the gas-phase concentrations of DINP and DEHP in the large chamber were reduced slightly, due to the decease of mass transfer coefficient and emission rate. During the last phase, when the temperature of the chamber was reduced to 25 C, phthalate concentrations dropped instantly and steeply due to the significantly reduced emissions. However, they did not decrease as quickly thereafter because of desorption of phthalates from the internal surfaces of the large chamber. A fundamental mechanistic model was developed to interpret the experimental results in the large chamber based on the emission characteristics obtained in the small chamber measurements. Reasonable agreement was obtained between the model calculation and experimental data. Further model simulations show that temperature and air mixing above the source material have important effects on the fate of phthalates, while the impact of air change rate (ACH) is not significant.
Chemosphere, Aug 1, 2001
Measured emission factors are the experimental data used to represent emission characteristics of... more Measured emission factors are the experimental data used to represent emission characteristics of volatile organic compounds (VOCs) from testing materials under dynamic chamber test conditions. A simple empirical model that describes the measured emission factors will be very useful for practical purposes. In this study, a power law model was compared with a widely used ®rst-order exponential decay model in their ability to describe measured emission factors of wood-based panel materials. It was demonstrated that the power law model is a better choice than the ®rst-order model for describing emission characteristics for short-term (less than 100 h) experimental data. The power law model was also more superior in predicting long-term (up to 900 h) emission factors.
PubMed, May 1, 2013
Background: The presence of volatile organic compounds (VOCs) in indoor air may have negative hea... more Background: The presence of volatile organic compounds (VOCs) in indoor air may have negative health consequences, ranging from mild irritation to more severe illnesses. Indoor air data are required to assess Canadian population exposure to these VOCs. Data and methods: The 2009 to 2011 Canadian Health Measures Survey (CHMS) included an indoor air component. Respondents who went to the mobile examination centre to participate in the physical measures section of the survey were asked to deploy an indoor air sampler in their homes for 7 consecutive days. Data were collected for 84 VOCs. Control samples that were implemented included duplicates and blanks. Results: Of the 4,686 indoor air samplers given to CHMS respondents, 4,581 were deployed and returned to the testing laboratory. Data from 3,857 samplers met the criteria for inclusion in the CHMS indoor air data files. Thirteen VOCs had a mean percentage difference between the duplicate pairs greater than 30%. The field and cleaning blank geometric means and medians were lower than 1 μg/m³ for 83 VOCs. Interpretation: The high percentage of mobile examination centre participants who deployed samplers in their homes, the sampler return rate, and the quality of the data obtained demonstrate the feasibility of relying on respondents to handle indoor air samplers for large-scale collection of residential VOC data.
Environmental Pollution, Sep 1, 2019
Three hexachloronorbornene-based flame retardants and five polybrominated diphenyl ethers (PBDEs)... more Three hexachloronorbornene-based flame retardants and five polybrominated diphenyl ethers (PBDEs) were measured in 414 human plasma samples, (169 from children, 167 from mothers, and 78 from fathers), collected from 200 families between 2014 and 2016. The median concentration of P PBDEs (sum of BDE-47,-99, À100, À153 and À183) was 13.2 ng/g lipid for child, 9.03 ng/g lipid for mother and 12.7 ng/ g lipid for father, respectively. Among the hexachloronorbornene-based flame retardants, Dec 602 was the most frequently detected chemical. Significant and positive correlations between the concentrations of PBDE congeners as well as between Dec 602 and Dec 603 were observed. Concentrations of PBDE congeners also showed significant and positive correlations in paired samples from family members (child-mother-father), while Dec 602 was the only hexachloronorbornene-based flame retardant whose concentrations correlated between family members, and only in mother-father paired samples. This is the largest study to date focusing on measuring and correlating HRFs in children and their parents living in the same household. The results convey important information on human exposure to measured HFRs, which can help researchers and regulators more clearly understand the influence of diet and the home environment.
Scientific Reports
Vaping is gaining in popularity. However, there is still much that remains unknown about the pote... more Vaping is gaining in popularity. However, there is still much that remains unknown about the potential risk and harms of vaping. Formation of oxidative products is one of such areas that are not well understood. In this study, we used an in-situ thermal desorption GC/MS method to investigate the formation of oxidative products of several monoterpenes at or below typical vaping temperatures. Among the five tested monoterpenes, the unchanged portion of the parent compound in the vapour varied from 97 to 98% for myrcene to 11–28% for terpinolene. The majority of formed oxidative products in the vapour have a molecular weight of 134 (loss of two hydrogens), 150 (insertion of one oxygen and loss of two hydrogen atoms) or 152 (insertion of one oxygen atom). Three products, likely to be p-(1-propenyl)-toluene, β-pinone and fenchol were also observed. This is the first in-situ thermal desorption GC/MS study to investigate the possible formation of oxidative products of monoterpenes, one of ...
Environmental Pollution, 2020
In previous studies, the total content of urinary phthalate metabolites was commonly used to eval... more In previous studies, the total content of urinary phthalate metabolites was commonly used to evaluate human exposure to phthalates. However, phthalate metabolites are mainly present in urine in two forms, conjugated and free. These metabolite forms in urine are more relevant to the biotransformation pathways of the phthalates in humans. Therefore, the concentration of these forms is more relevant to exposure related health outcomes than total content. In this study, instead of measuring total content, the free-and conjugated-form concentrations of phthalate metabolites in the urine of fertile and infertile men were measured. The main metabolites in urine of both groups are monoethyl phthalate (MEP) and the di-(2-ethylhexyl) phthalate (DEHP) metabolites. The geometric means of their both conjugated-and free-forms in the infertile group were higher than in the fertile group, specifically, 24.3 and 43.4 mg/g creatinine vs 8.5 and 28.9 mg/g creatinine, respectively, for MEP, and 50.0 and 9.1 mg/g creatinine vs 39.1 and 8.4 mg/g creatinine, respectively for total DEHP metabolites. We investigated the correlations of freeand conjugated-form phthalate metabolite concentrations between the infertile and fertile group as well as among different phthalate metabolites. The results showed that there was a statistically significant difference between the infertile and fertile group for monobenzyl phthalate (MBzP) in both free-form and conjugated-form. However, there was only a statistically significant difference between the two groups for conjugated-form MEP and MEHP, and no statistically significant difference between the two groups for free-form MEP and MEHP. The results of the Pearson correlation test revealed that the correlations between DEHP metabolites and the correlations between mid-sized phthalate metabolites (mono-n-butyl phthalate (MnBP), mono-isobutyl phthalate (MiBP) and mono-benzyl phthalate (MBzP)) were stronger than between these two clusters of metabolites. This study is the first attempt to examine possible effects of conjugated-form concentrations of phthalate metabolites on human fertility. The results of this study suggest that conjugated-form and free-form concentrations of urinary phthalate metabolites may be appropriate biomarkers for assessing human exposure to phthalates and association with health outcomes.
Proceedings of the National Academy of Sciences, 2019
Significance Athletes and children are playing on artificial turfs. However, the health risk asso... more Significance Athletes and children are playing on artificial turfs. However, the health risk associated with exposure to crumb rubber from artificial turfs is unknown for higher vertebrates. Here, we employed chicken embryo as a developing amniote vertebrate model to show that toxic leachate from artificial athletic turf infill impairs the early development of chicken, notably brain and cardiovascular system. This study triggers a scientific discussion as to whether crumb rubber is an appropriate infill material for artificial fields.
Building and Environment, 2016
Indoor environments contain a wide range of synthetic products that emit a variety of semivolatil... more Indoor environments contain a wide range of synthetic products that emit a variety of semivolatile organic compounds (SVOCs). Among these SVOCs, organophosphorus compounds (OPs) are ubiquitous in indoor environments with relatively high concentrations. This study investigated the occurrence of seven OPs including triphenylphosphine oxide (TPPO) in three different types of indoor spaces (offices, conference halls and laboratories) of an institute building. A total of 39 airborne particulate matter (PM10) and ten settled dust samples were analyzed. Among the seven target OPs, tri(2-chloroethyl) phosphate (TCEP), tri(chloropropyl) phosphate (TCPP) and TPPO were the major ones found in these samples. TPPO was for the first time identified in indoor environments with levels up to 94 ng/m 3 in indoor air and 1.1 µg/g in the indoor settled dust. Positive identity of TPPO in the samples was confirmed by comparisons of the mass spectrum of TPPO peak with that of TPPO standard and same GC retention time of TPPO from samples and from the standard. Compositions of OPs in these samples revealed different sources of OPs present in the indoor spaces. An equilibrium model was used to predict OPs in settled indoor dust from their corresponding levels found in indoor airborne particulate matters. There was a statistically significant correlation between predicted and measured OPs in settled dust in all three types of indoor spaces. The difference between measured and model predicted OP levels in settled dust was in the general range of predictions reported for indoor air SVOCs.
AIMS Environmental Science, 2015
Levels of polybrominated biphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs), and dichlorod... more Levels of polybrominated biphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs), and dichlorodiphenyltrichloroethane and its degradation products (DDTs) in the environment (ambient air, soil and aquatic mammals) and in humans from the developing regions (Africa, Latin America, and South-southeast Asia) are reviewed. Higher DDTs levels in certain parts of the developing regions due to agricultural applications and disease control measures are evident. The data however do not indicate higher levels of PCBs and PBDEs in the developing regions compared to developed countries. We also compared globally the levels of these chemicals in human milk sampled since year 2000. Human milk data again showed higher DDTs levels in the developing regions. For PBDEs, though current levels in human milk from the developing regions do not exceed levels found in the developed countries, data suggest the levels of PBDEs in the developing regions may be on the rise.
Building and Environment, 2015
This study investigated phthalate emissions from vinyl flooring in a large-scale chamber. Vinyl f... more This study investigated phthalate emissions from vinyl flooring in a large-scale chamber. Vinyl flooring materials were examined for their phthalates content; one with high contents of diisononyl phthalate (DINP) and di(2-ethylhexyl) phthalate (DEHP) was selected for emissions testing in a small chamber at two different temperatures. Using the same type of vinyl flooring, large-scale chamber experiments were then conducted in three testing phases. In the first phase, the gas-phase concentrations of DINP and DEHP in the large chamber at 36 C were about three times lower than those in the small chamber under the same temperature, which is consistent with its lower area/volume ratio. In the second phase, when a large air mixing fan inside the chamber was replaced with a small fan, the gas-phase concentrations of DINP and DEHP in the large chamber were reduced slightly, due to the decease of mass transfer coefficient and emission rate. During the last phase, when the temperature of the chamber was reduced to 25 C, phthalate concentrations dropped instantly and steeply due to the significantly reduced emissions. However, they did not decrease as quickly thereafter because of desorption of phthalates from the internal surfaces of the large chamber. A fundamental mechanistic model was developed to interpret the experimental results in the large chamber based on the emission characteristics obtained in the small chamber measurements. Reasonable agreement was obtained between the model calculation and experimental data. Further model simulations show that temperature and air mixing above the source material have important effects on the fate of phthalates, while the impact of air change rate (ACH) is not significant.
![Research paper thumbnail of Follicle growth is inhibited by benzo-[a]-pyrene, at concentrations representative of human exposure, in an isolated rat follicle culture assay](https://attachments.academia-assets.com/112617869/thumbnails/1.jpg)
](Human Reproduction, 2007
BACKGROUND: The adverse effects of cigarette smoking on human fertility have been well documented... more BACKGROUND: The adverse effects of cigarette smoking on human fertility have been well documented. However, the mechanism(s) underlying the detrimental effects of cigarette smoking are unknown. Using a novel isolated rat follicle culture assay, we tested the hypothesis that benzo-[a]-pyrene (B[a]P), a constituent of cigarette smoke, can inhibit follicle growth. METHODS: B[a]P levels were quantified in the serum and follicular fluid (FF) of women undergoing in vitro fertilization (IVF) treatment exposed to mainstream smoke (n 5 19) and non-smokers (n 5 10) by gas chromatography mass spectrometry. Isolated rat follicles were cultured with increasing concentrations of B[a]P (1.5-300 ng ml 21) and follicle diameter was measured daily. RESULTS: Mean (+ + + + +Standard error of the mean) B[a]P) was quantified in the serum (0.40 + + + + + 0.13 ng ml 21) and FF (1.32 + + + + + 0.68 ng ml 21) of women who smoke. IVF stimulation and outcome measures were similar between female smokers and non-smokers with the exception of implantation rate and pregnancy rate, which were both significantly lower (P < 0.05) in the MS group. B[a]P treatment significantly reduced rat follicle diameter and attenuated FSH stimulated growth in a dose-dependent manner, beginning at 1.5 ng ml 21. CONCLUSIONS: Our data suggest that B[a]P, at levels representative of those measured in human FF, may adversely affect follicle development and be an ovarian toxicant.
Chemosphere, 2001
Measured emission factors are the experimental data used to represent emission characteristics of... more Measured emission factors are the experimental data used to represent emission characteristics of volatile organic compounds (VOCs) from testing materials under dynamic chamber test conditions. A simple empirical model that describes the measured emission factors will be very useful for practical purposes. In this study, a power law model was compared with a widely used ®rst-order exponential decay model in their ability to describe measured emission factors of wood-based panel materials. It was demonstrated that the power law model is a better choice than the ®rst-order model for describing emission characteristics for short-term (less than 100 h) experimental data. The power law model was also more superior in predicting long-term (up to 900 h) emission factors.
ABSTRACT A material emission database was developed for 48 building materials based on ASTM test ... more ABSTRACT 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. Une base de données des émissions des matériaux a été compilée pour 48 matériaux de construction conformément à la méthode d'essai ASTM. Cette base de données consiste en des coefficients de modèles pour cinq à six des composés organiques volatils (COV) les plus communs émis par les matériaux de construction répertoriés. Les chercheurs se sont servis d'un modèle de loi de puissance pour décrire les émissions des matériaux secs, dont l'aggloméré de bois, le contreplaqué, le panneau à copeaux orientés (OSB), le bois massif, le panneau de placoplâtre, le carreau de plafond insonorisant, le revêtement de sol en vinyle, la thibaude et le tapis. Les émissions de COV des matériaux mouillés ont été divisées en trois régions temporelles à modèles d'émission distincts, dont la pression de vapeur et un modèle de la couche limite, un modèle de décroissance exponentielle et un modèle de loi de puissance. Les matériaux mouillés retenus sont la teinture de bois, le vernis polyuréthanne, l'adhésif, le mastic, l'encaustique et la peinture. Puisque la base de données est reliée à un logiciel qui simule la qualité de l'air intérieur dans une zone unique, elle peut servir à explorer les échanges entre la sélection des matériaux et les stratégies de ventilation. RES
Animal studies have shown that developmental exposures to polybrominated diphenyl ethers (PBDE) p... more Animal studies have shown that developmental exposures to polybrominated diphenyl ethers (PBDE) permanently affect blood/liver balance of lipids. No human study has evaluated associations between in utero exposures to persistent organic pollutants (POPs) and later life lipid metabolism. In this pilot, maternal plasma levels of PBDEs (BDE-47, BDE-99, BDE-100, and BDE-153) and polychlorinated biphenyls (PCB-138, PCB-153, and PCB-180) were determined at delivery in participants of GESTation and Environment (GESTE) cohort. Total cholesterol (TCh), triglycerides (TG), low and high density lipoproteins (LDL-C and HDL-C), total lipids (TL), and PBDEs were determined in serum of 147 children at ages 6-7. General linear regression was used to estimate the relationship between maternal POPs and child lipid levels with adjustment for potential confounders, and adjustment for childhood POPs. In utero BDE-99 was associated with lower childhood levels of TG (p=0.003), and non-significantly with H...
Journal of the Air Waste Management Association, Feb 1, 2003
Three diesel fuels, one oil sand-derived (OSD) diesel serving as base fuel, one cetane-enhanced b... more Three diesel fuels, one oil sand-derived (OSD) diesel serving as base fuel, one cetane-enhanced base fuel, and one oxygenate [diethylene glycol dimethyl ether (DEDM)]-blended base fuel, were tested for their emission characterizations in vehicle exhaust on a light-duty diesel truck that reflects the engine technology of the 1994 North American standard. Both the cetane-enhanced and the oxygenate-blended fuels were able to reduce regulated [CO, particulate matter (PM), total hydrocarbon (THC)] and nonregulated [polyaromatic hydrocarbons (PAHs), carbonyls, and other volatile organic chemicals] emissions, except for nitrogen oxides (NO(x)), compared with the base fuel. Although burning a fuel that contains oxygen could conceivably yield more oxygenated compounds in emissions, the oxygenate-blended diesel fuel resulted in reduced emissions of formaldehyde along with hydrocarbons such as benzene, 1,3-butadiene, and PAHs. Reductions in nitro-PAH emissions have been observed in both the cetane-enhanced and oxygenated fuels. This further demonstrates the benefits of using a cetane enhancer and the oxygenated fuel component.
Food Additives and Contaminants Part a Chemistry Analysis Control Exposure and Risk Assessment, Jun 23, 2009
An isotope dilution method based on solvent extraction followed by GC-MS analysis was developed a... more An isotope dilution method based on solvent extraction followed by GC-MS analysis was developed and used to determine aniline in vegetable and fruit samples collected from the Canadian total diet study. Aniline was not detected in any of the 23 vegetable samples from the 2005 total diet study at a method detection limit of 0.01 mg kg(-1). Among the 16 fruit samples, it was detected only in apple samples, with an average concentration of 0.278 mg kg(-1). Aniline was not detected in apple samples collected in the 2002, 2003, 2006 or 2007 total diet studies, but it was detected in the apple samples collected from the 2001 and 2004 studies, at concentrations of 0.085 and 0.468 mg kg(-1), respectively. The average aniline concentration for the 2001, 2004 and 2005 apple samples was 0.277 mg kg(-1). Good repeatability of the method was observed with replicate analysis of apple samples, with relative standard deviations (RSD) ranging 3.8-21% and an average of 11%.
Http Dx Doi Org 10 1080 10473289 2005 10464701, Mar 1, 2012
A real-time monitoring methodology to determine diesel fine particles in diesel emissions has bee... more A real-time monitoring methodology to determine diesel fine particles in diesel emissions has been evaluated. The range of particle size captured by the monitor was ϳ0.1 m to 1 m. DustTrak real-time monitors were connected to the dilution tunnel of the vehicle exhaust to measure the emissions during the vehicle tests under both dynamic and steady-state driving conditions, and concentration data were recorded every 5 sec. Test variation of the real-time monitoring among different test days was similar to that measured by traditional filter-based gravimetric method, whereas the repeatability of the monitor data within the same-day tests was better than that of gravimetric method. Correlations between the two methods were established for different fuels tested on a single light duty vehicle. When the emissions from the reference fuel was used to convert the monitor's response to diesel fuels, the levels determined by the real-time monitor were consistent with those measured by gravimetric method among different fuels tested. Use of the real-time monitor could provide information on the levels of fine particles that is more relevant to the public health than the total particles.
Journal of Hazardous Materials, Dec 1, 2013
h i g h l i g h t s • 2,2 ,4,4-Tetrabromodiphenyl ether (BDE-47) was found transformed to six les... more h i g h l i g h t s • 2,2 ,4,4-Tetrabromodiphenyl ether (BDE-47) was found transformed to six less brominated BDE analogs under UV irradiation. • BDE-47 was found degraded faster in liquid phase than in gas phase. • Two brominated phenols were formed in the transformation of BDE-47 in gas phase. • The bromine on the ortho positions of the phenyl rings was found lost first to form 2,4,4-tribromodiphenyl ether (BDE-28). • The more volatile less brominated BDEs are a source of secondary pollutants in the environment.
Chemosphere, Dec 1, 1999
A method for estimating VOC emission rates from hydrocarbon solvent-based indoor materials has be... more A method for estimating VOC emission rates from hydrocarbon solvent-based indoor materials has been developed. The estimation is based on the assumption that the emission rate of individual VOCs is proportional to its molar fraction in the evaporative mixture at the time, its saturated pure vapor pressure and total remaining VOCs in the material. The paper demonstrates, through three hydrocarbon solvent-based polyurethane surface coating materials, a practical way to calculate these three parameters using chemical composition analysis results. The estimated total VOC emission rates were in good agreement with the results of weight loss experiments.
Building and Environment, Jul 1, 2015
This study investigated phthalate emissions from vinyl flooring in a large-scale chamber. Vinyl f... more This study investigated phthalate emissions from vinyl flooring in a large-scale chamber. Vinyl flooring materials were examined for their phthalates content; one with high contents of diisononyl phthalate (DINP) and di(2-ethylhexyl) phthalate (DEHP) was selected for emissions testing in a small chamber at two different temperatures. Using the same type of vinyl flooring, large-scale chamber experiments were then conducted in three testing phases. In the first phase, the gas-phase concentrations of DINP and DEHP in the large chamber at 36 C were about three times lower than those in the small chamber under the same temperature, which is consistent with its lower area/volume ratio. In the second phase, when a large air mixing fan inside the chamber was replaced with a small fan, the gas-phase concentrations of DINP and DEHP in the large chamber were reduced slightly, due to the decease of mass transfer coefficient and emission rate. During the last phase, when the temperature of the chamber was reduced to 25 C, phthalate concentrations dropped instantly and steeply due to the significantly reduced emissions. However, they did not decrease as quickly thereafter because of desorption of phthalates from the internal surfaces of the large chamber. A fundamental mechanistic model was developed to interpret the experimental results in the large chamber based on the emission characteristics obtained in the small chamber measurements. Reasonable agreement was obtained between the model calculation and experimental data. Further model simulations show that temperature and air mixing above the source material have important effects on the fate of phthalates, while the impact of air change rate (ACH) is not significant.
Chemosphere, Aug 1, 2001
Measured emission factors are the experimental data used to represent emission characteristics of... more Measured emission factors are the experimental data used to represent emission characteristics of volatile organic compounds (VOCs) from testing materials under dynamic chamber test conditions. A simple empirical model that describes the measured emission factors will be very useful for practical purposes. In this study, a power law model was compared with a widely used ®rst-order exponential decay model in their ability to describe measured emission factors of wood-based panel materials. It was demonstrated that the power law model is a better choice than the ®rst-order model for describing emission characteristics for short-term (less than 100 h) experimental data. The power law model was also more superior in predicting long-term (up to 900 h) emission factors.
PubMed, May 1, 2013
Background: The presence of volatile organic compounds (VOCs) in indoor air may have negative hea... more Background: The presence of volatile organic compounds (VOCs) in indoor air may have negative health consequences, ranging from mild irritation to more severe illnesses. Indoor air data are required to assess Canadian population exposure to these VOCs. Data and methods: The 2009 to 2011 Canadian Health Measures Survey (CHMS) included an indoor air component. Respondents who went to the mobile examination centre to participate in the physical measures section of the survey were asked to deploy an indoor air sampler in their homes for 7 consecutive days. Data were collected for 84 VOCs. Control samples that were implemented included duplicates and blanks. Results: Of the 4,686 indoor air samplers given to CHMS respondents, 4,581 were deployed and returned to the testing laboratory. Data from 3,857 samplers met the criteria for inclusion in the CHMS indoor air data files. Thirteen VOCs had a mean percentage difference between the duplicate pairs greater than 30%. The field and cleaning blank geometric means and medians were lower than 1 μg/m³ for 83 VOCs. Interpretation: The high percentage of mobile examination centre participants who deployed samplers in their homes, the sampler return rate, and the quality of the data obtained demonstrate the feasibility of relying on respondents to handle indoor air samplers for large-scale collection of residential VOC data.
Environmental Pollution, Sep 1, 2019
Three hexachloronorbornene-based flame retardants and five polybrominated diphenyl ethers (PBDEs)... more Three hexachloronorbornene-based flame retardants and five polybrominated diphenyl ethers (PBDEs) were measured in 414 human plasma samples, (169 from children, 167 from mothers, and 78 from fathers), collected from 200 families between 2014 and 2016. The median concentration of P PBDEs (sum of BDE-47,-99, À100, À153 and À183) was 13.2 ng/g lipid for child, 9.03 ng/g lipid for mother and 12.7 ng/ g lipid for father, respectively. Among the hexachloronorbornene-based flame retardants, Dec 602 was the most frequently detected chemical. Significant and positive correlations between the concentrations of PBDE congeners as well as between Dec 602 and Dec 603 were observed. Concentrations of PBDE congeners also showed significant and positive correlations in paired samples from family members (child-mother-father), while Dec 602 was the only hexachloronorbornene-based flame retardant whose concentrations correlated between family members, and only in mother-father paired samples. This is the largest study to date focusing on measuring and correlating HRFs in children and their parents living in the same household. The results convey important information on human exposure to measured HFRs, which can help researchers and regulators more clearly understand the influence of diet and the home environment.
Scientific Reports
Vaping is gaining in popularity. However, there is still much that remains unknown about the pote... more Vaping is gaining in popularity. However, there is still much that remains unknown about the potential risk and harms of vaping. Formation of oxidative products is one of such areas that are not well understood. In this study, we used an in-situ thermal desorption GC/MS method to investigate the formation of oxidative products of several monoterpenes at or below typical vaping temperatures. Among the five tested monoterpenes, the unchanged portion of the parent compound in the vapour varied from 97 to 98% for myrcene to 11–28% for terpinolene. The majority of formed oxidative products in the vapour have a molecular weight of 134 (loss of two hydrogens), 150 (insertion of one oxygen and loss of two hydrogen atoms) or 152 (insertion of one oxygen atom). Three products, likely to be p-(1-propenyl)-toluene, β-pinone and fenchol were also observed. This is the first in-situ thermal desorption GC/MS study to investigate the possible formation of oxidative products of monoterpenes, one of ...
Environmental Pollution, 2020
In previous studies, the total content of urinary phthalate metabolites was commonly used to eval... more In previous studies, the total content of urinary phthalate metabolites was commonly used to evaluate human exposure to phthalates. However, phthalate metabolites are mainly present in urine in two forms, conjugated and free. These metabolite forms in urine are more relevant to the biotransformation pathways of the phthalates in humans. Therefore, the concentration of these forms is more relevant to exposure related health outcomes than total content. In this study, instead of measuring total content, the free-and conjugated-form concentrations of phthalate metabolites in the urine of fertile and infertile men were measured. The main metabolites in urine of both groups are monoethyl phthalate (MEP) and the di-(2-ethylhexyl) phthalate (DEHP) metabolites. The geometric means of their both conjugated-and free-forms in the infertile group were higher than in the fertile group, specifically, 24.3 and 43.4 mg/g creatinine vs 8.5 and 28.9 mg/g creatinine, respectively, for MEP, and 50.0 and 9.1 mg/g creatinine vs 39.1 and 8.4 mg/g creatinine, respectively for total DEHP metabolites. We investigated the correlations of freeand conjugated-form phthalate metabolite concentrations between the infertile and fertile group as well as among different phthalate metabolites. The results showed that there was a statistically significant difference between the infertile and fertile group for monobenzyl phthalate (MBzP) in both free-form and conjugated-form. However, there was only a statistically significant difference between the two groups for conjugated-form MEP and MEHP, and no statistically significant difference between the two groups for free-form MEP and MEHP. The results of the Pearson correlation test revealed that the correlations between DEHP metabolites and the correlations between mid-sized phthalate metabolites (mono-n-butyl phthalate (MnBP), mono-isobutyl phthalate (MiBP) and mono-benzyl phthalate (MBzP)) were stronger than between these two clusters of metabolites. This study is the first attempt to examine possible effects of conjugated-form concentrations of phthalate metabolites on human fertility. The results of this study suggest that conjugated-form and free-form concentrations of urinary phthalate metabolites may be appropriate biomarkers for assessing human exposure to phthalates and association with health outcomes.
Proceedings of the National Academy of Sciences, 2019
Significance Athletes and children are playing on artificial turfs. However, the health risk asso... more Significance Athletes and children are playing on artificial turfs. However, the health risk associated with exposure to crumb rubber from artificial turfs is unknown for higher vertebrates. Here, we employed chicken embryo as a developing amniote vertebrate model to show that toxic leachate from artificial athletic turf infill impairs the early development of chicken, notably brain and cardiovascular system. This study triggers a scientific discussion as to whether crumb rubber is an appropriate infill material for artificial fields.
Building and Environment, 2016
Indoor environments contain a wide range of synthetic products that emit a variety of semivolatil... more Indoor environments contain a wide range of synthetic products that emit a variety of semivolatile organic compounds (SVOCs). Among these SVOCs, organophosphorus compounds (OPs) are ubiquitous in indoor environments with relatively high concentrations. This study investigated the occurrence of seven OPs including triphenylphosphine oxide (TPPO) in three different types of indoor spaces (offices, conference halls and laboratories) of an institute building. A total of 39 airborne particulate matter (PM10) and ten settled dust samples were analyzed. Among the seven target OPs, tri(2-chloroethyl) phosphate (TCEP), tri(chloropropyl) phosphate (TCPP) and TPPO were the major ones found in these samples. TPPO was for the first time identified in indoor environments with levels up to 94 ng/m 3 in indoor air and 1.1 µg/g in the indoor settled dust. Positive identity of TPPO in the samples was confirmed by comparisons of the mass spectrum of TPPO peak with that of TPPO standard and same GC retention time of TPPO from samples and from the standard. Compositions of OPs in these samples revealed different sources of OPs present in the indoor spaces. An equilibrium model was used to predict OPs in settled indoor dust from their corresponding levels found in indoor airborne particulate matters. There was a statistically significant correlation between predicted and measured OPs in settled dust in all three types of indoor spaces. The difference between measured and model predicted OP levels in settled dust was in the general range of predictions reported for indoor air SVOCs.
AIMS Environmental Science, 2015
Levels of polybrominated biphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs), and dichlorod... more Levels of polybrominated biphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs), and dichlorodiphenyltrichloroethane and its degradation products (DDTs) in the environment (ambient air, soil and aquatic mammals) and in humans from the developing regions (Africa, Latin America, and South-southeast Asia) are reviewed. Higher DDTs levels in certain parts of the developing regions due to agricultural applications and disease control measures are evident. The data however do not indicate higher levels of PCBs and PBDEs in the developing regions compared to developed countries. We also compared globally the levels of these chemicals in human milk sampled since year 2000. Human milk data again showed higher DDTs levels in the developing regions. For PBDEs, though current levels in human milk from the developing regions do not exceed levels found in the developed countries, data suggest the levels of PBDEs in the developing regions may be on the rise.
Building and Environment, 2015
This study investigated phthalate emissions from vinyl flooring in a large-scale chamber. Vinyl f... more This study investigated phthalate emissions from vinyl flooring in a large-scale chamber. Vinyl flooring materials were examined for their phthalates content; one with high contents of diisononyl phthalate (DINP) and di(2-ethylhexyl) phthalate (DEHP) was selected for emissions testing in a small chamber at two different temperatures. Using the same type of vinyl flooring, large-scale chamber experiments were then conducted in three testing phases. In the first phase, the gas-phase concentrations of DINP and DEHP in the large chamber at 36 C were about three times lower than those in the small chamber under the same temperature, which is consistent with its lower area/volume ratio. In the second phase, when a large air mixing fan inside the chamber was replaced with a small fan, the gas-phase concentrations of DINP and DEHP in the large chamber were reduced slightly, due to the decease of mass transfer coefficient and emission rate. During the last phase, when the temperature of the chamber was reduced to 25 C, phthalate concentrations dropped instantly and steeply due to the significantly reduced emissions. However, they did not decrease as quickly thereafter because of desorption of phthalates from the internal surfaces of the large chamber. A fundamental mechanistic model was developed to interpret the experimental results in the large chamber based on the emission characteristics obtained in the small chamber measurements. Reasonable agreement was obtained between the model calculation and experimental data. Further model simulations show that temperature and air mixing above the source material have important effects on the fate of phthalates, while the impact of air change rate (ACH) is not significant.
Human Reproduction, 2007
BACKGROUND: The adverse effects of cigarette smoking on human fertility have been well documented... more BACKGROUND: The adverse effects of cigarette smoking on human fertility have been well documented. However, the mechanism(s) underlying the detrimental effects of cigarette smoking are unknown. Using a novel isolated rat follicle culture assay, we tested the hypothesis that benzo-[a]-pyrene (B[a]P), a constituent of cigarette smoke, can inhibit follicle growth. METHODS: B[a]P levels were quantified in the serum and follicular fluid (FF) of women undergoing in vitro fertilization (IVF) treatment exposed to mainstream smoke (n 5 19) and non-smokers (n 5 10) by gas chromatography mass spectrometry. Isolated rat follicles were cultured with increasing concentrations of B[a]P (1.5-300 ng ml 21) and follicle diameter was measured daily. RESULTS: Mean (+ + + + +Standard error of the mean) B[a]P) was quantified in the serum (0.40 + + + + + 0.13 ng ml 21) and FF (1.32 + + + + + 0.68 ng ml 21) of women who smoke. IVF stimulation and outcome measures were similar between female smokers and non-smokers with the exception of implantation rate and pregnancy rate, which were both significantly lower (P < 0.05) in the MS group. B[a]P treatment significantly reduced rat follicle diameter and attenuated FSH stimulated growth in a dose-dependent manner, beginning at 1.5 ng ml 21. CONCLUSIONS: Our data suggest that B[a]P, at levels representative of those measured in human FF, may adversely affect follicle development and be an ovarian toxicant.
Chemosphere, 2001
Measured emission factors are the experimental data used to represent emission characteristics of... more Measured emission factors are the experimental data used to represent emission characteristics of volatile organic compounds (VOCs) from testing materials under dynamic chamber test conditions. A simple empirical model that describes the measured emission factors will be very useful for practical purposes. In this study, a power law model was compared with a widely used ®rst-order exponential decay model in their ability to describe measured emission factors of wood-based panel materials. It was demonstrated that the power law model is a better choice than the ®rst-order model for describing emission characteristics for short-term (less than 100 h) experimental data. The power law model was also more superior in predicting long-term (up to 900 h) emission factors.
ABSTRACT A material emission database was developed for 48 building materials based on ASTM test ... more ABSTRACT 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. Une base de données des émissions des matériaux a été compilée pour 48 matériaux de construction conformément à la méthode d'essai ASTM. Cette base de données consiste en des coefficients de modèles pour cinq à six des composés organiques volatils (COV) les plus communs émis par les matériaux de construction répertoriés. Les chercheurs se sont servis d'un modèle de loi de puissance pour décrire les émissions des matériaux secs, dont l'aggloméré de bois, le contreplaqué, le panneau à copeaux orientés (OSB), le bois massif, le panneau de placoplâtre, le carreau de plafond insonorisant, le revêtement de sol en vinyle, la thibaude et le tapis. Les émissions de COV des matériaux mouillés ont été divisées en trois régions temporelles à modèles d'émission distincts, dont la pression de vapeur et un modèle de la couche limite, un modèle de décroissance exponentielle et un modèle de loi de puissance. Les matériaux mouillés retenus sont la teinture de bois, le vernis polyuréthanne, l'adhésif, le mastic, l'encaustique et la peinture. Puisque la base de données est reliée à un logiciel qui simule la qualité de l'air intérieur dans une zone unique, elle peut servir à explorer les échanges entre la sélection des matériaux et les stratégies de ventilation. RES
Animal studies have shown that developmental exposures to polybrominated diphenyl ethers (PBDE) p... more Animal studies have shown that developmental exposures to polybrominated diphenyl ethers (PBDE) permanently affect blood/liver balance of lipids. No human study has evaluated associations between in utero exposures to persistent organic pollutants (POPs) and later life lipid metabolism. In this pilot, maternal plasma levels of PBDEs (BDE-47, BDE-99, BDE-100, and BDE-153) and polychlorinated biphenyls (PCB-138, PCB-153, and PCB-180) were determined at delivery in participants of GESTation and Environment (GESTE) cohort. Total cholesterol (TCh), triglycerides (TG), low and high density lipoproteins (LDL-C and HDL-C), total lipids (TL), and PBDEs were determined in serum of 147 children at ages 6-7. General linear regression was used to estimate the relationship between maternal POPs and child lipid levels with adjustment for potential confounders, and adjustment for childhood POPs. In utero BDE-99 was associated with lower childhood levels of TG (p=0.003), and non-significantly with H...
Journal of the Air Waste Management Association, Feb 1, 2003
Three diesel fuels, one oil sand-derived (OSD) diesel serving as base fuel, one cetane-enhanced b... more Three diesel fuels, one oil sand-derived (OSD) diesel serving as base fuel, one cetane-enhanced base fuel, and one oxygenate [diethylene glycol dimethyl ether (DEDM)]-blended base fuel, were tested for their emission characterizations in vehicle exhaust on a light-duty diesel truck that reflects the engine technology of the 1994 North American standard. Both the cetane-enhanced and the oxygenate-blended fuels were able to reduce regulated [CO, particulate matter (PM), total hydrocarbon (THC)] and nonregulated [polyaromatic hydrocarbons (PAHs), carbonyls, and other volatile organic chemicals] emissions, except for nitrogen oxides (NO(x)), compared with the base fuel. Although burning a fuel that contains oxygen could conceivably yield more oxygenated compounds in emissions, the oxygenate-blended diesel fuel resulted in reduced emissions of formaldehyde along with hydrocarbons such as benzene, 1,3-butadiene, and PAHs. Reductions in nitro-PAH emissions have been observed in both the cetane-enhanced and oxygenated fuels. This further demonstrates the benefits of using a cetane enhancer and the oxygenated fuel component.
Food Additives and Contaminants Part a Chemistry Analysis Control Exposure and Risk Assessment, Jun 23, 2009
An isotope dilution method based on solvent extraction followed by GC-MS analysis was developed a... more An isotope dilution method based on solvent extraction followed by GC-MS analysis was developed and used to determine aniline in vegetable and fruit samples collected from the Canadian total diet study. Aniline was not detected in any of the 23 vegetable samples from the 2005 total diet study at a method detection limit of 0.01 mg kg(-1). Among the 16 fruit samples, it was detected only in apple samples, with an average concentration of 0.278 mg kg(-1). Aniline was not detected in apple samples collected in the 2002, 2003, 2006 or 2007 total diet studies, but it was detected in the apple samples collected from the 2001 and 2004 studies, at concentrations of 0.085 and 0.468 mg kg(-1), respectively. The average aniline concentration for the 2001, 2004 and 2005 apple samples was 0.277 mg kg(-1). Good repeatability of the method was observed with replicate analysis of apple samples, with relative standard deviations (RSD) ranging 3.8-21% and an average of 11%.
Http Dx Doi Org 10 1080 10473289 2005 10464701, Mar 1, 2012
A real-time monitoring methodology to determine diesel fine particles in diesel emissions has bee... more A real-time monitoring methodology to determine diesel fine particles in diesel emissions has been evaluated. The range of particle size captured by the monitor was ϳ0.1 m to 1 m. DustTrak real-time monitors were connected to the dilution tunnel of the vehicle exhaust to measure the emissions during the vehicle tests under both dynamic and steady-state driving conditions, and concentration data were recorded every 5 sec. Test variation of the real-time monitoring among different test days was similar to that measured by traditional filter-based gravimetric method, whereas the repeatability of the monitor data within the same-day tests was better than that of gravimetric method. Correlations between the two methods were established for different fuels tested on a single light duty vehicle. When the emissions from the reference fuel was used to convert the monitor's response to diesel fuels, the levels determined by the real-time monitor were consistent with those measured by gravimetric method among different fuels tested. Use of the real-time monitor could provide information on the levels of fine particles that is more relevant to the public health than the total particles.