Phthalates in dormitory and house dust of northern Chinese cities: Occurrence, human exposure, and risk assessment

Polybrominated diphenyl ethers in student dormitory microenvironments: Concentrations, sources, and human exposure

Microenvironments, such as student dormitories, differ from general residential environments. They are characterized by small spaces, poor air circulation, high personnel densities, and electronic products, such as computers that are turned on for extended periods, leading to increased pollution concentrations. The limited space and poor air circulation reduce migration of contaminants, such as polybrominated diphenyl ethers (PBDEs), making it easier for PBDEs to accumulate. However, few studies have been conducted on small group dwellings, including student dormitory dwellings. We collected dust samples from student dormitories of a university to analyze the characteristics and traceability of PBDEs in dormitory microenvironments. The results showed that PBDE congeners were widely present in university dormitories and the order of median concentration of ∑10PBDEs was as follows: male old-fashioned dormitory (273 ng/g) > female four-person dormitory (132 ng/g) > female two-person dormitory (132 ng/g) > male two-person dormitory (96.2 ng/g) > female old-fashioned dormitory (91.6 ng/g) > male four-person apartment (51.8 ng/g). BDE-209 was the most abundant PBDE congener, followed by BDE-47, and BDE-28. PBDEs were also found in typical electrical appliances, with higher concentrations in laptops than in desktops, and higher concentrations in desktops than in idle ones. According to Spearman correlation and Principal Component Analysis (PCA), we also found that boards and wallpaper materials were common sources of contamination in the microenvironment of student dormitories, and that female dormitories had more sources of PBDE emissions. Human exposure to PBDEs in students is below the US Environmental Protection Agency reference dose. Although exposure to PBDEs generated in dormitories does not pose a significant health risk, the potential hazards of PBDEs to the reagent environment remain to be investigated.

Occurrence of BTX and PAHs in underground drinking water of coking contaminated sites: Linkage with altitude and health risk assessment by boiling-modified models

The safety of underground drinking water has received widespread attention. However, few studies have focused on the occurrence and health risks of pollutants in underground drinking water of coking contaminated sites. In this study, the distribution characteristics, sources, and human health risks of benzene, toluene, xylene (BTX) and polycyclic aromatic hydrocarbons (PAHs) in underground drinking water from a typical coking contaminated site in Shanxi of China were investigated. The average concentrations of BTX and PAHs in coking plant (CP) were 5.1 and 4.8 times higher than those in residential area (RA), respectively. Toluene and Benzene were the main BTX, while Acenaphthene, Fluorene, and Pyrene were the main PAHs. Concentrations of BTX/PAHs were negatively correlated with altitude, revealing altitude might be an important geological factor influencing spatial distribution of BTX/PAHs. PMF model demonstrated that the BTX/PAHs pollution in RA mainly originated from coking industrial activities. Health risk assessments were conducted by a modified US EPA-based model, in which environmental concentrations were replaced by residual concentrations after boiling. Residual ratios of different BTX/PAHs were determined by boiling experiments to be 9.4-93.8 %. The average total carcinogenic risks after boiling were decreased from 2.6 × 10-6 to 1.4 × 10-6 for adults, and from 4.3 × 10-6 to 2.1 × 10-6 for children, suggesting boiling was an effective strategy to reduce the carcinogenic risks from BTX/PAHs, especially for ingestion pathway. Monte Carlo simulation results matched well with the calculated results, suggesting the uncertainty was acceptable and the risk assessment results were reliable. This study provided useful information for revealing the spatial distribution of BTX/PAHs in underground drinking water of coking contaminated sites, understanding their linkage with altitude, and also helped to more accurately evaluate the health risks by using the newly established boiling-modified models.

Multi-source exposure and health risks of phthalates among university students in Northeastern China

The endocrine disruptor phthalates (PAEs) are widely used as important chemical additives in a variety of areas around the globe. PAEs are toxic to reproduction and development and may adversely affect the health of adolescents. Risk assessments of exposure to PAEs from different sources are more reflective of actual exposure than single-source assessments. We used personal exposure parameters to estimate the dose of PAEs to 107 university students from six media (including dormitory dust, dormitory air, clothing, food, disposable food containers, and personal care products (PCPs)) and three exposure routes (including ingestion, inhalation, and dermal absorption). Individual factors and lifestyles may affect PAE exposure to varying degrees. Based on a positive matrix factorization (PMF) model, the results indicated that the main sources of PAEs in dust were indoor building materials and plastics, while PCPs and adhesives were the major sources of airborne PAEs. The relative contribution of each source to PAE exposure showed that food and air were the primary sources of dimethyl phthalate (DMP) and dibutyl phthalate (DBP). Air source contributed the most to diethyl phthalate (DEP) exposure, followed by PCPs. Food was the most significant source of diisobutyl phthalate (DiBP), benzyl butyl phthalate (BBP), and bis(2-ethylhexyl) phthalate (DEHP) exposure. Additionally, the exposure of DEHP to dust was not negligible. The ingestion pathway was the most dominant among the three exposure pathways, followed by dermal absorption. The non-carcinogenic risk of PAEs from the six sources was within acceptable limits. DEHP exhibits a low carcinogenic risk. We suggest university students maintain good hygienic and living habits to minimize exposure to PAEs.

Dust-phase phthalates in university dormitories in Beijing, China: pollution characteristics, potential sources, and non-dietary oral exposure

This study aimed to determine dust-phase phthalate levels in 112 dormitories of 14 universities during autumn and winter, investigate their potential sources, and estimate phthalate exposure via dust ingestion. Twelve phthalates were detected, among which di-(2-ethylhexyl) phthalate (DEHP) and dicyclohexyl phthalate (DCHP) were the most abundant, followed by di-isobutyl phthalate (DiBP) and di-n-butyl phthalate (DnBP). The median concentrations and contributions of DCHP and DEHP were the highest. The contributions of di-n-octyl phthalate and di-nonyl phthalate were higher in winter than in autumn. Potential sources included iron furniture, chemical fiber textiles, clothes, and personal care products. Medium-density fiberboard furniture is a potential sink for phthalates. In two seasons, DEHP, DCHP, DiBP, and DnBP were the main phthalates ingested by college students . The median oral exposure of ten phthalates was higher in females than in males. College students have a high risk of exposure to DEHP in dormitories.

Comprehensive assessment of phthalates in indoor dust across China between 2007 and 2019: Benefits from regulatory restrictions

China is the largest producer and consumer of phthalates in the world. However, it remains unclear whether China's phthalate restrictions have alleviated indoor phthalate pollution. We extracted the concentrations of dimethyl phthalate (DMP), diethyl phthalate (DEP), dibutyl phthalate (DBP), diisobutyl phthalate (DIBP), benzyl butyl phthalate (BBP), and bis(2-ethylhexyl) phthalate (DEHP) in indoor dust at 2762 sites throughout China between 2007 and 2019 from the published literature. Based on these data, we investigated the effects of phthalate restrictions and environmental factors on the temporal-spatial distribution and sources of phthalates and estimated human exposure and risk of phthalates. The results revealed that the mean concentrations of phthalates in indoor dust throughout China decreased in the following order: DEHP > DBP > DIBP > DMP > DEP > BBP. The concentrations of six phthalates were generally higher in northern and central-western China than in southern regions. BBP and DEHP concentrations decreased by 73.5% and 17.9%, respectively, from 2007 to 2019. Sunshine was a critical environmental factor in reducing phthalate levels in indoor dust. Polyvinyl chloride materials, personal care products, building materials, and furniture were the primary sources of phthalates in indoor dust. The phthalates in indoor dust posed the most significant threat to children and older adults. This study provides a picture of phthalate pollution, thus supporting timely and effective policies and legislation.

Distribution of polycyclic aromatic hydrocarbons in indoor/outdoor window films and the indoor film/air partition of northeastern Chinese college dormitories

Indoor window films can represent short-term air pollution conditions of indoor environment through rapidly capturing organic contaminants as effective passive air samplers. To investigate the temporal variation, influence factors of polycyclic aromatic hydrocarbons (PAHs) in indoor window films, and the exchange behavior with gas phase in college dormitories, 42 pairs window films of interior and exterior window surfaces and corresponding indoor gas phase and dust samples were collected monthly in six selected dormitories, Harbin, China, from August to December 2019 and September 2020. The average concentration of ∑₁₆PAHs in indoor window films (398 ng/m²) was significantly (p < 0.01) lower than that in outdoors (652 ng/m²). In addition, the median indoor/outdoor ∑₁₆PAHs concentration ratio was close to 0.5, showing that outdoor air acted as a major PAH source to indoor environment. The 5-ring PAHs were mostly dominant in window films whereas the 3-ring PAHs contributed mostly in gas phase. 3-ring PAHs and 4-ring PAHs were both important contributors for dormitory dust. Window films showed stable temporal variation, i.e. PAH concentrations in heating months were higher than those in non-heating months. The atmospheric O₃ concentration was the main influence factor of PAHs in indoor window films. PAHs with low molecular weight in indoor window films rapidly reached film/air equilibrium phase within in dozens of hours. The large deviation in the slope of the log K_F-A versus log K_OA regression line from that in reported equilibrium formula might be the difference between the window film composition and octanol.

Distribution and health risks of organic micropollutants from home dusts in Malaysia

Indoor dust is an important medium to evaluate human exposure to emerging organic contaminants. The principal aim of this study was to determine overall status of organic micropollutants (OMPs) of indoor dust in Kuala Lumpur, Malaysia and assess their corresponding health risks. One hundred thirty-three OMPs, ascribed to 13 chemical groups, were screened by Automated Identification and Quantification System with a GC-MS database. The concentrations of OMPs ranged between 460 and 4000 μg/g, with the median concentration of 719 μg/g. The dominant chemical groups were ascribed to n-alkanes (median: 274 μg/g), plasticizers (151 μg/g), sterols (120 μg/g), and pesticides (42.6 μg/g). Cholestrol was the most abundant compound (median: 115 μg/g). Different sources and usage patterns of OMPs in various houses were expected. Toxicity values of OMPs were obtained from existing databases or predicted by quantitative structure-activity relationship models. Cumulative hazard quotients for OMPs through ingestion route were lower than one for all the dust samples, demonstrating that there was no remarkable non-cancer risk. The cancer risks of these OMPs were greater than 10^-4, with cholestrol dominating 99.1% of the carcinogenic risks, which suggested that there was a significant cancer risk. This study might offer a benchmark to ensure the safety of chemical usages in future in Malaysia.

Phthalates in dormitory dust and human urine: A study of exposure characteristics and risk assessments of university students

Phthalate diesters (PAEs) are prevalent and potentially toxic to human health. The university dormitory represents a typical and relatively uniform indoor environment. This study evaluated the concentrations of phthalate monoesters (mPAEs) in urine samples from 101 residents of university status, and the concentrations of PAEs in dust collected from 36 corresponding dormitories. Di-(2-ethylhexyl) phthalate (DEHP, median: 68.0 μg/g) was the major PAE in dust, and mono-ethyl phthalate (47.9 %) was the most abundant mPAE in urine. The levels of both PAEs in dormitory dust and mPAEs in urine were higher in females than in males, indicating higher PAE exposure in females. Differences in lifestyles (dormitory time and plastic product use frequency) may also affect human exposure to PAEs. Moreover, there were significant positive correlations between the estimated daily intakes of PAEs calculated by using concentrations of PAEs in dust (EDI_D) and mPAEs in urine (EDI_U), suggesting that PAEs in dust could be a significant source of human exposure to PAEs. The value of EDI_D/EDI_U for low molecular weight PAEs (3-6 carbon atoms in their backbone) was lower than that of high molecular weight PAEs. The contribution rate of various pathways to PAE exposure illustrated that non-dietary ingestion (87.8 %) was the major pathway of human exposure to PAEs in dust. Approximately 4.95 % of university students' hazard quotients of DEHP were >1, indicating that there may be some health risks associated with DEHP exposure among PAEs. Furthermore, it is recommended that some measures be taken to reduce the production and application of DEHP.

Multiresidue analytical method for high production volume chemicals in dust samples, occurrence and human exposure assessment

A multiresidue analytical method based on pressurised liquid extraction and gas-chromatography mass spectrometry was developed to determine 22 compounds belonging to different chemical families in indoor dust.: Seven organophosphate esters, six phthalate esters, three benzotriazoles, five benzothiazoles and four benzenesulfonamides were included in the present study, all of them belonging to the category of high production volume chemicals (HPVCs). Apparent recoveries ranged between 45% and 123% and method quantification limits ranged from 0.03 μg/g to 3.8 μg/g. The occurrence of the selected HPVCs was evaluated in indoor dust from different locations in the Tarragona (Catalonia, Spain) region. Two benzenesulfonamides, ortho-toluenesulfonamide and para-toluenesulfonamide, were detected in dust samples for the first time. Phthalate esters and organophosphate esters were the most abundant compounds found, and di-(2-ethylhexyl) phthalate (DEHP) was determined at the highest concentrations. With the data obtained, human exposure was assessed by calculating the estimated daily intakes (EDI) via ingestion and dermal contact. Non-carcinogenic and carcinogenic risk assessments found no risks in any of the scenarios tested, which included two age classes (children and adults) and two possible exposure scenarios (median and worst-case scenario), except for the evaluation of carcinogen risk due to ingestion of DEHP in the worst-case scenario.

Phthalate Exposure and Oxidative/Nitrosative Stress in Childhood Asthma: A Nested Case-Control Study with Propensity Score Matching

Whether low-dose phthalate exposure triggers asthma among children, and its underlying mechanisms, remain debatable. Here, we evaluated the individual and mixed effects of low-dose phthalate exposure on children with asthma and five (oxidative/nitrosative stress/lipid peroxidation) mechanistic biomarkers—8-hydroxy-2′-deoxyguanosine (8-OHdG), 8-nitroguanine (8-NO₂Gua), 4-hydroxy-2-nonenal-mercapturic acid (HNE-MA), 8-isoprostaglandin F2α (8-isoPF2α), and malondialdehyde (MDA)—using a propensity score-matched case-control study (case vs. control = 41 vs. 111). The median monobenzyl phthalate (MBzP) concentrations in the case group were significantly higher than those in the control group (3.94 vs. 2.52 ng/mL, p = 0.02), indicating that dust could be an important source. After adjustment for confounders, the associations of high monomethyl phthalate (MMP) (75th percentile) with 8-NO₂Gua (adjusted odds ratio (aOR): 2.66, 95% confidence interval (CI): 1.03–6.92) and 8-isoPF2α (aOR: 4.04, 95% CI: 1.51–10.8) and the associations of mono-iso-butyl phthalate (MiBP) with 8-isoPF2α (aOR: 2.96, 95% CI: 1.13–7.79) were observed. Weighted quantile sum regression revealed that MBzP contributed more than half of the association (56.8%), followed by MiBP (26.6%) and mono-iso-nonyl phthalate (MiNP) (8.77%). Our findings supported the adjuvant effect of phthalates in enhancing the immune system response.

Indoor exposure to phthalates and its burden of disease in China

China's profoundly rapid modernization in the past two decades has resulted in dramatic changes in indoor environmental exposures. Among these changes, exposure to phthalates has attracted increasing attention. We aimed to characterize indoor phthalate exposure and to estimate the disease burden attributable to indoor phthalate pollution from 2000 to 2017 in China. We integrated the national exposure level of indoor phthalates from literature through systematic review and Monte Carlo simulation. Dose-response relationships between phthalate exposure and health outcomes were obtained by systematic review and meta-analysis. Based on existing models for assessing probabilities of causation and a comprehensive review of available data, we calculated the disability-adjusted life years (DALYs) among the general Chinese population resulting from exposure to indoor phthalate pollution. We found that DnBP, DiBP, and DEHP were the most abundant phthalates in indoor environments of residences, offices, and schools with medians of national dust phase concentration from 74.5 µg/g to 96.3 µg/g, 39.6 µg/g to 162.5 µg/g, 634.2 µg/g to 1,394.7 µg/g, respectively. The national equivalent exposure for children to phthalates in settled dust was higher than that of adults except for DiBP and DnOP. Dose-response relationships associated with DEP, DiBP, DnBP, BBzP, and DEHP exposures were established. Between 2000 and 2017, indoor phthalate exposure in China has led to 3.32 million DALYs per year, accounting for 0.90% of total DALYs across China. The annual DALY associated with indoor phthalate pollution in China was over 2000 people per million, which is about 2~3 times of the DALY loss due to secondhand smoke (SHS) in six European countries or the sum of the DALY loss caused by indoor radon and formaldehyde in American homes. Our study indicates a considerable socioeconomic impact of indoor phthalate exposure for a modernizing human society. This suggest the need for relevant national standard and actions to reduce indoor phthalate exposure.

Association of childhood rhinitis with phthalate acid esters in household dust in Shanghai residences

OBJECTIVE

Phthalate acid esters (PAEs) have been identified to be associated with children's health. Present study was conducted to assess associations between PAEs in household dust and childhood rhinitis.

METHODS

Based on phase II of CCHH study (China, Children, Home, Health) conducted in Shanghai, China, 266 indoor dust samples were collected from participants' families. Concentrations of PAEs in dust samples were measured by chemical treatment and gas chromatograph-mass spectrometer. Information about individuals and residences was surveyed by questionnaires. Logistic regression models were applied to obtain the associations between PAEs and childhood rhinitis.

RESULTS

Higher concentrations of benzyl butyl phthalate (BBP) were found in those families with children who had diagnosed rhinitis. Significantly higher concentrations of bis(2-ethylhexyl) phthalate (DEHP) and PAEs with high molecular weight (HMW-PAEs) were found in the positive group of lifetime rhinitis. Using the multiple and ordinal logistic regression models adjusted by covariates, dibutyl phthalate (DBP), DEHP, and HMW-PAEs were found to be significantly associated with diagnosed rhinitis. Boys who exposure to higher concentrations of DBP, DEHP, HMW-PAEs, and total PAEs have significant associations with diagnosed rhinitis compared with girls who exposure to lower concentration of PAEs.

CONCLUSIONS

Present observational study indicated that exposure to high concentrations of DBP, DEHP, and HMW-PAEs in house settled dust was a risk factor for rhinitis for children, especially for boys.

Occurrence and exposure risk assessment of organic micropollutants in indoor dust from Malaysia

Indoor dust is an important source of human exposure to hazardous organic micropollutants (OMPs) because humans spend about 90 % of their time in the indoor environments. This study initially analyzed the concentrations and compositions of OMPs in the dust of different indoor environments from Kuala Lumpur, Malaysia. A total of 57 OMPs were detected and assigned to 7 chemical classes in this study. The total concentration of OMPs ranged from 5980 to 183,000 ng/g, with the median concentration of 46,400 ng/g. Personal care products, organophosphate esters, and pesticides were the dominant groups, with their median concentrations at 12,000, 10,000, and 5940 ng/g, respectively. The concentrations and compositions of influential OMPs varied in different microenvironments, suggesting different sources and usage patterns in the house. Then, the noncarcinogenic and carcinogenic risks of exposure to these substances for diverse age groups were assessed based on the median concentration. Cumulative noncarcinogenic risks of these OMPs via ingestion pathway were estimated to be negligible (1.41 × 10^-4 - 1.87 × 10^-3). The carcinogenic risks of these OMPs were higher than 10^-6 (1.63 × 10^-6 - 6.17 × 10^-6) and should be noted. Theobromine accounted for more than 89 % of the cumulative cancer risk, implying that the carcinogenic risk of theobromine needs further monitoring in the future. Toddler was the most affected group for cancer risk among all the age groups, regardless of the microenvironments. These findings from this study may provide a benchmark for future efforts to ensure the safety of indoor dust for the local residents.

Phthalates in house dust in Chinese urban residences: Concentrations, partition, origin and determinants

Exposure to phthalates poses adverse health impacts to human beings. In this study, we analyzed 7 phthalates in dust samples, which were collected with vacuum cleaner from 40 to 31 residences in Beijing in summer and winter, respectively. The major phthalates (median concentration in the summer and winter, respectively) were DiBP (55 and 40 ng/mg), DnBP (99 and 30 ng/mg) and DEHP (795 and 335 ng/mg). The concentrations were significantly influenced by season and residence time of house dust. The concentrations of phthalates in dust on plastic surfaces were highest, followed by those on wooden and fabric surfaces. The dust-air partition coefficients (K_d) were calculated: the median values were 0.13, 0.02 and 5.62 m³/mg in the summer and 0.06, 0.018 and 0.76 m³/mg in the winter for DiBP, DnBP and DEHP, respectively. A comparison with K_d* at equilibrium state suggested that partition between air and dust deviated from equilibrium state in both seasons. The results also revealed that dust-phthalates in the summer may completely originate from source materials via direct transfer and external physical process; while dust-phthalates in the winter may come from both air (via partition) and source material (via direct transfer and external physical process). The influence of temperature on dust-phthalate concentrations differed by season, owing to different origin of dust-phthalates in two seasons. Polar organic components in dust, which are products of reactions between O₃ and unsaturated hydrocarbons in dust, likely played an important role in fate and transport of phthalates. The presence of them resulted in the significant associations between dust-phthalate concentrations and air humidity in the summer. Moreover, the impacts of indoor PM_2.5 concentrations, traffic conditions surrounding residence, household lifestyle and number of occupants were also observed. The mechanisms behind those observations were discussed.

A Novel Personal Passive Sampler for Collecting Gaseous Phthalates

Dermal absorption of gaseous chemicals is an important contributor to increased health risk and has yet to be adequately addressed due to the lack of available sampling techniques. In the present study, a novel personal passive sampler consisting of a housing (embracing a polydimethylsiloxane (PDMS) disk as the sorbent phase, a membrane filter, and a stainless-steel mesh) and a watchband (traditional wristband) was constructed and used to characterize gaseous phthalates (PAEs) near the air-skin interface. In a real-life setting, the utility of the passive sampler was validated by comparing the composition profiles of PAEs in the PDMS disks and in active samples and watchbands. The compositions of PAEs were consistent in disks and gaseous constituents from ambient air, with low-molecular-weight (<306 g mol^-1) PAEs accounting for 87-100% and approximately 100%, respectively. Appreciable amounts of diisononyl phthalate, diisodecyl phthalate, dinonyl phthalate, and skin lipid (e.g., squalene) were detected in watchbands but not in disks. Apparently, the passive sampler can prevent particles and skin-related chemicals from adhering to the disk and collect gaseous PAEs only. The vast majority of PAEs in watchbands was associated with nongaseous constituents. The present study demonstrated that the sampling strategy is a key factor in exposure assessment.

Analysis and health risk assessment of phthalate esters (PAEs) in indoor dust of preschool and elementary school centers in city of Tehran, Iran

Individuals spend a lot of time indoors; thus they are generally exposed to phthalates used in consumer products. Therefore, those exposed to phthalates as indoor contaminants are at high risks. The present study was conducted to evaluate the carcinogenic and non-carcinogenic hazard of phthalate esters (PAEs), like dimethyl phthalate, diethyl phthalate, di(nbutyl) phthalate, butyl benzyl phthalate, dioctyl phthalate, and di(2-ethylhexyl) phthalate in the dust obtained from 21 schools in Tehran, in 2019. A total of 63 indoor dust specimens were obtained by a vacuum cleaner. After transferring dust samples to the laboratory, 100 mg of each sample was centrifuged and mixed with 20 ml acetone and kept through a night and ultrasonicated within 30 min. Eventually, PAEs' contents were measured via gas chromatography-mass spectrometry. Based on the findings, median concentrations of DMP, DEP, DnBP, BBP, DEHP, and DnOP were 0.90, 0.10, 6.0, 0.20, 118.30, and 4.10 mg kg^-1 respectively. Moreover, the overall average daily exposure doses (ADD) of phthalate esters via dust ingestion, skin contact, and inhalation were 1.56E-03, 1.70E-06, and 1.56E-07 mg kg^-1 day^-1, respectively, and the lifetime average daily exposure doses (LADD) were 1.83E-04, 2.34E-08, and 2.46E-08 mg kg^-1 day^-1, respectively; thus ingestion of dust particles was found to be the main pathway of exposure to phthalate for non-carcinogenic and carcinogenic risks. Although based on the results, the studied samples were below the US Environmental Protection Agency threshold of 1.00E-06, due to the disadvantages of phthalates in human safety, these kinds of investigations are helpful in understanding the main ways of exposure to PAEs and providing a science-based framework for the future attempts for mitigating the PAEs indoor emissions.

Associations between phthalic acid esters in household dust and childhood asthma in Shanghai, China

Phthalic acid esters (PAEs) have a negative impact on human health and are widely distributed in China. As part of the China, Children, Home, Health (CCHH) study, we investigated the associations between childhood asthmatic symptoms and PAEs in settled house dust in Shanghai, China. We found that di-2-ethylhexyl phthalate (DEHP), dibutyl phthalate (DBP), and diisobutyl phthalate (DiBP) were abundant in the indoor environment. A total of 27 % of children suffered from diagnosed asthma. The Mann-Whitney U test and multiple logistic regression were used to obtain the associations between PAEs and childhood asthmatic symptoms. Stratification analysis was performed to reveal the influence of gender on the associations between PAE exposure and target symptoms. Compared with low concentrations of PAEs, high concentrations of high molecular weight PAEs (HMW-PAEs) were significantly associated with childhood diagnosed asthma (adjusted odds ratios (AORs) > 1, P < 0.05). Moreover, significantly negative associations were found between high concentrations of DiBP and current cough (AORs<1, P < 0.05). All significantly positive associations were observed among girls, and most of the associations of dimethyl phthalate (DMP) and diethyl phthalate (DEP) exposure with the studied symptoms among girls were higher than those among boys. Exposure to PAEs may be a risk factor for asthmatic symptoms in children, especially in girls.

Exposure to phthalates and correlations with phthalates in dust and air in South China homes

We spend more than half of our daily time in indoor environments, and the contributions of phthalates present in it to total exposure are important. Here, we determined phthalate concentrations in paired indoor settled dust/air and their metabolites in human urine from 100 general families in south China to explore such kind of effect. The total concentrations of phthalates/metabolites were 48.7-2850 μg/g, 279-5080 ng/m³ and 10.7-2840 ng/mL in the indoor dust, air and urine samples, respectively. Among all targets, di-n-butyl phthalate, di-isobutyl phthalate and di-(2-ethylhexyl) phthalate and their metabolites were the predominant compounds. The daily intakes (DIs) of phthalates via dust or air decreased with age, except for infant, and the values of dust ingestion, air inhalation and air dermal uptake were 2720 ± 2460, 1300 ± 973 and 3590 ± 2890 ng/kg/day for toddlers and 236 ± 194, 360 ± 179 and 1120 ± 586 ng/kg/day for adults, respectively. The ratios of DIs from air to dust were greater than 1.0 for people in all age groups, and the ratio was the highest for adults. Furthermore, the contributions of phthalates from indoor dust and air to total DIs from all sources (estimated from urinary phthalate metabolites) were 0.60%-5.23% and 2.65%-12.2% for different ages, respectively. Our results indicated that indoor air was a quite important source for human exposure to phthalates in indoor environment in south China.

Characteristics of dust-phase phthalates in dormitory, classroom, and home and non-dietary exposure in Beijing, China

The phthalate concentrations in dust from undergraduate dormitories, classrooms, and homes in Beijing, China, were measured in April 2017. We analyzed the characteristics of phthalates in dust from three environments. In addition, we estimated the daily intake of phthalates via three pathways using Monte Carlo simulations. The detection frequency of eight phthalates in dust ranges from 74.5 to 100%. Di (2-ethylhexyl) phthalate (DEHP), di-n-butyl phthalate (DnBP), and di-isobutyl phthalate (DiBP) are the most abundant phthalates. The median proportion of DEHP in dust is the highest, ranging from 67.1 to 72.9%. The PMF results indicated that two, four, and three types of phthalate sources exist in home, dormitory, and classroom, respectively. The differences in the phthalate concentrations between sunny and shaded rooms and urban and suburban classrooms are insignificant, whereas that between male and female dormitories is significant. The total daily intake of DEHP, DnBP, and DiBP ranges from 97.3 to 336 ng/ (kg·day). The oral intake for DEHP in classrooms and the dermal intake of DnBP and DiBP in homes are the highest. The carcinogenic risk of DEHP to university students is the highest in classrooms and the total carcinogenic risk of the three environments is 4.70 × 10^-6.

Phthalates in House and Dormitory Dust: Occurrence, Human Exposure and Risk Assessment

Phthalates are one of ubiquitous contaminants in the indoor environment. In this study, we analyzed concentrations and profiles of 9 phthalates in dust samples collected from houses and university dormitories in Nanjing, China. The total concentrations of phthalates in house and dormitory dust ranged from 111.4 to 3599.1 µg/g and 86.1 to 1262.3 µg/g, respectively. Phthalates in house was significantly higher than that in dormitory dust (p < 0.01). Di(2-ethylhexyl) phthalate (DEHP), dibutyl phthalate (DBP) and di-isobutyl phthalate (DiBP) were the three predominant compounds and accounted for more than 98% of total phthalates in the two microenvironments. The estimated daily intake (EDI) of phthalates, carcinogenic risk (CR) of DEHP, and hazard index (HI) values of DEHP, DBP and DiBP were estimated. Except for adults, the CR of DEHP for four subgroups (infants, toddlers, children, and teenagers) had exceeded the limitation, implying that they are at the risk of exposure to DEHP through dust ingestion.

Multi-residue analysis of several high-production-volume chemicals present in the particulate matter from outdoor air. A preliminary human exposure estimation

A multi-residue method based on gas chromatography-mass spectrometry combined with pressurised liquid extraction was developed to determine seven organophosphate esters (OPEs), six phthalate esters (PAEs), four benzotriazoles (BTRs), five benzothiazoles (BTHs) and four benzenesulfonamides (BSAs) in particulate matter samples from outdoor air. All of these compounds are among the named high-production volume chemicals (HPVCs) and some of them have shown to be harmful to human, therefore they have been subject for legal regulation in order to control their production and usage. Under optimised conditions, high recovery values (>80%) and low detection limits (pg m-3) were obtained for most of the compounds with accuracy values between 83% and 118%. Some samples from two locations surrounded by different industry activities showed the widespread occurrence of all the PAEs, followed by some OPEs. Diethylhexyl phthalate (DEHP) was the most abundant compound with concentrations ranging from 1.9 to 97.7 ng m-3. With the concentrations found, estimated daily intakes through outdoor inhalation were calculated for each contaminant and for different population groups classified by age (infants, children and adults) in two possible exposure scenarios (low and high). Then, hazard quotients and carcinogenic risks were estimated for several compounds, those that had toxicological parameters available. This preliminary result showed no significant risks via ambient inhalation for the exposed population, however more research is needed to confirm the present results.

Occurrence of bisphenol A and its alternatives in paired urine and indoor dust from Chinese university students: Implications for human exposure

Bisphenol analogs (BPs), as the industrial chemicals, are widely used in consumer products. Limited information exists regarding human exposure to BPs in university students in China. In this study, we detected concentrations of seven BPs, namely bisphenol A (BPA), bisphenol AF (BPAF), bisphenol P (BPP), bisphenol AP (BPAP), bisphenol Z (BPZ), bisphenol S (BPS), and bisphenol F (BPF), in paired urine (n = 160) and indoor dust samples (n = 40) from university students in South China. High detection rates and levels (median) was found in BPA in paired urine (99%, 3.57 ng/mL) and indoor dust (80%, 2.98 μg/g) samples, followed by BPS (88%, 0.24 ng/mL; 78%, 0.22 μg/g). These findings suggest that BPA remains the major BPs used in consumer products. A positive relationship between urinary ∑BPs (sum of six BPs) concentration and indoor dust was observed (r = 0.444, p < 0.01), indicated that exposure to non-dietary BPs may also be significant to human exposure. The median EDI_urine values (ng/kg bw/day) of ∑BPs in males (119.6) were relatively higher than (p < 0.05) those in females (84.6). By contrast, the median EDI_dust of BPs (except for BPAF) in dust form female dormitories were slightly higher than that in dust from male dormitories. Notably, BPF was the most ingested from indoor dust (dormitory dust). This study is the first time to document the occurrence of BPs in paired urine and indoor dust in university students from China.

Occurrence and human health risks of phthalates in indoor air of laboratories

Phthalate acid esters (PAEs) are of serious concern as a human health risk due to their ubiquitous presence in indoor air. In the present study, fifteen PAEs in the indoor air samples from physical, chemical, and biological laboratories in Guangzhou, southern China were analysed using gas chromatography mass spectrometry. Extremely high levels of PAEs of up to 6.39 × 10⁴ ng/m³ were detected in some laboratories. Diisobutyl phthalate (DiBP), di(methoxyethyl) phthalate (DMEP), and di-n-butyl phthalate (DBP) were the dominant PAEs with median levels of 0.48 × 10³, 0.44 × 10³, and 0.39 × 10³ ng/m³, respectively, followed by di-(2-propylheptyl) phthalate (DPHP) and di(2-ethylhexyl) phthlate (DEHP) (median levels: 0.16 × 10³ and 0.13 × 10³ ng/m³, respectively). DMEP and DPHP were found for the first time in indoor air. Principal component analysis indicated that profiles of PAEs varied greatly among laboratory types, suggesting notable variations in sources. The results of independent samples t-tests showed that levels of PAEs were significantly influenced by various environmental conditions. Both the non-carcinogenic and carcinogenic health risks from human exposure to PAEs based on the daily exposure dose in laboratory air were acceptable. Further research should be conducted to investigate the long-term health effects of exposure to PAEs in laboratories.

PM2.5 bound phthalates in four metropolitan cities of China: Concentration, seasonal pattern and health risk via inhalation

Phthalates (PAEs) are in a group of artificial chemicals with potential adverse effects to human health and they can be frequently detected in environmental matrices due to its extensive usage. However, seasonal patterns of concentrations in atmosphere and risks posed by PAEs in airborne PM_2.5 to Chinese population have not been well characterized. During the period of November 2015 to March 2017, samples of fine particulate matter (PM_2.5) were collected in four cities of Guangzhou, Shanghai, Beijing and Harbin, which are major metropolitan areas of various latitudes of China. Concentrations of fourteen PAEs in airborne PM_2.5 were quantified using Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS). Estimated daily intakes (EDIs), hazard quotients (HQs) and hazard index (HI) were calculated. Lifetime average daily doses (LADD) and incremental lifetime cancer risks (ILCR) of di(2-ethylhexyl) phthalate (DEHP) for four age groups, which divide with infant, toddler, adolescent and adult, by inhalation route were evaluated. Dimethyl phthalate (DMP), Diethyl phthalate (DEP), Di-n-butyl phthalate (DBP), and DEHP were the four major PAEs contaminants in these PM_2.5 samples. The sum concentrations of DMP, DEP, DBP and DEHP in Guangzhou, Shanghai, Beijing and Harbin ranged from 32.5-76.1, 10.1-101, 8.02-107 and 13.5-622 ng/m³, with mean concentrations of 59.1, 50.8, 43.8 and 136 ng/m³, respectively. The concentration of total PAEs in PM_2.5 from higher latitudes city (Harbin) was higher than those from lower latitudes cities (Guangzhou and Shanghai). Total concentrations of PAEs were significantly higher during warmer seasons than those during colder seasons among the four cities. Although the EDIs, HQs, and HI for all age groups were less than the threshold set by the U.S. Environmental Protection Agency (US EPA) and European Food Safety Authority (EFSA), the highest values of 70-years ILCR from Shanghai and Harbin were 1.2 × 10^-6 and 1.3 × 10^-6, which were slightly beyond the acceptable level of 10^-6. These findings reveal that the cancer risks of DEHP bound to PM_2.5 in these two cites should be of particular concern.

Semi-volatile organic compounds in infant homes: Levels, influence factors, partitioning, and implications for human exposure

While infants are developing, they are easily affected by toxic chemicals existing in their environments, such as semi-volatile organic compounds (SVOCs): phthalates, polycyclic aromatic hydrocarbons (PAHs), polybrominated diphenyl ethers (PBDEs), and organophosphate esters (OPEs). However, the specific living environment of infants, including increased plastic products and foam floor mats, may increase the presence of these chemicals. In this study, 68 air, dust, and window film samples were collected from homes, with 3- to 6-month-old infant occupants, to analyze phthalates, PAHs, PBDEs, and OPEs. High detection rates and concentrations suggest that these SVOCs are widespread in infant environments and are associated with cooking methods, smoking habits, the period of time after decoration, and room floors. The partitioning behavior of SVOCs indicates that the logarithms of the dust/gas-phase air partition coefficient (logK_D) and the window film/gas-phase air partition coefficient (logK_F) in homes are not at an equilibrium state when the logarithm of the octanol/air partition coefficient (logK_OA) is less than 8 or greater than 11. Considering the 3 exposure routes, ingestion and dermal absorption have become the main routes of infant exposure to phthalates and OPEs, and ingestion and inhalation have become the dominant routes of exposure to PAHs and PBDEs. The total carcinogenic risk of SVOCs, which have carcinogenic toxicities, via ingestion and dermal absorption for infants in homes exceeds the acceptable value, suggesting that the current levels of these SVOCs in homes might pose a risk to infant health.

Indoor phthalate concentrations in residences in Shihezi, China: implications for preschool children's exposure and risk assessment

Despite the risks associated with phthalate exposure, there are few studies emphasizing preschool children's exposure to phthalates in residences in Northwest China. In this study, seven phthalates from indoor dust samples were measured in 50 residences in Shihezi, China. Preschool children's exposure doses via non-dietary intake were calculated by Monte Carlo simulation. Risk assessment was conducted by comparing the simulated exposure dose with benchmarks for reproductive toxicity and cancer specified in Proposition 65 of California. The detection frequencies for all selected phthalates were more than 75%, with the exception of benzyl butyl phthalate (BBP) and di-n-octyl phthalate (DNOP). Bis(2-ethylhexyl) phthalate (DEHP) was the most principal compound in the dust samples (median = 455 μg/g and 462 μg/g in the bedroom and living room, respectively). The simulation displayed that the median DBP daily intake was 1.5-1.9 μg/day/kg for preschool children in Shihezi, which was considered a high level compared with similar studies around the world. The risk assessment indicated that almost all preschool children face potential reproductive risk due to dibutyl phthalate (DBP) exposure, with medians of hazard index (HI) from 9.6 to 12.4 for all age groups. Therefore, from a children's health perspective, attention should be paid to reducing indoor phthalate pollution and exposure in this area.

Occupational exposure to respirable dust from the coal-fired power generation process: sources, concentration, and health risk assessment

To investigate the contamination levels of respirable dust released in the work environment and the induced workers' health risk at a coal-fired power plant, we collected 405 dust samples from different dusty workstations by personal sampling during the coal-fired power generation process. Then, an inhalation risk assessment model from the USEPA was combined with the Monte Carlo simulation method to quantitatively evaluate the health risk caused by dust inhalation. Of 10 workstations researched, the dust concentration in the most workstations exceeded the prescribed occupational exposure limit. Workers engaged in ash removal suffered the highest health risk at 4.08 × 10^-6 ± 2.85 × 10^-6 (95% CI), closely followed by those involved in other job categories. The results can contribute to the formulation of targeted dust prevention measures and implementation of risk management for the coal-fired power sector.

Urinary levels, composition profile and cumulative risk of bisphenols in preschool-aged children from Nanjing suburb, China

Due to the extensive use in consumer products, the bisphenols (BPs) pollution in the environments has aggravated and people are frequently exposed to BPs. In this research, four BPs, i.e., bisphenol A (BPA), bisphenol F (BPF), bisphenol S (BPS) and bisphenol AF (BPAF), were determined in urine samples collected from Gaochun District preschool-age children and the concentrations, distribution profiles, potential sources and cumulative risk assessment of the target compounds were studied. Total concentrations of 4 BPs ranged from 2 to 3113.1 ng/L, with the average concentration of 648.6 ng/L. BPA was the predominant congener (accounting for 94%), followed by BPS. Correlation analysis indicated a negative relationship between BPA and BPAF (R = -0.273, p < 0.05). The estimated daily intakes suggested that young females were more sensitive to BPs. Moreover, the cumulative risk for hazard quotient (HQ) of BPA has been evaluated and the results showed that no high risk had occurred. It provided basic information on the occurrence and human exposure to urinary BPs of preschool aged children from Gaochun District.

Organophosphate flame retardants in college dormitory dust of northern Chinese cities: Occurrence, human exposure and risk assessment

Organophosphate flame retardants (OPFRs) are widely added to consumer products and building materials, which may pose potential health risk to humans. But information on their contamination and human exposure in the indoor environment especially dormitories in northern China is rare. In this study, twelve OPFRs were investigated in college dormitory dust that collected from Harbin, Shenyang, and Baoding, in northern China. Indoor dust samples were also collected from homes and public microenvironments (PMEs) in Harbin for comparison. The median ∑OPFR concentrations in dormitory dust in Shenyang samples (8690 ng/g) were higher than those in Baoding (6540 ng/g) and Harbin (6190 ng/g). The median ∑OPFR concentrations in home dust (7150 ng/g) were higher than in dormitory and PME dust (5340 ng/g) in Harbin. Tris(2‑chloroethyl) phosphate (TCEP) and tris (2-chloroisopropyl) phosphate (TCIPP) were the most abundant chlorinated OPFRs, while triphenyl phosphate (TPHP) and tris(2‑butoxyethyl) phosphate (TBOEP) were the dominant non-chlorinated OPFRs. The daily intakes of ∑OPFR were estimated, with the median values for female students (2.45 ng/kg-day) higher than those for male students (2.15 ng/kg-day) while were similar to adults (2.45 ng/kg-day) in homes. The estimated daily intakes (EDI) of these OPFRs from indoor dust in Harbin were all below the recommended values. The calculated non-carcinogenic hazard quotients (10^-8-10^-3) from OPFRs were much lower than the theoretical risk threshold. Meanwhile, carcinogenic risk (CR) of tri‑n‑butyl phosphate (TNBP), TCEP, tris(2‑ethylhexyl) phosphate (TEHP), and tris(1,3‑dichloroisopropyl) phosphate (TDCIPP) were also estimated. The highest carcinogenic risk of TCEP for gender-specific and age-specific category range from 1.75 × 10^-7 to 2.46 × 10^-7 from exposure to indoor dust indicated a low potential carcinogenic risk for human exposure.

Exposure to commonly-used phthalates and the associated health risks in indoor environment of urban China

Rapid urbanization and modernization have increased exposures to phthalates from synthetic materials used indoors in China. However, exposure to phthalates from indoor environment and the associated health risks to the urban population have not been adequately characterized and documented. In this study, we summarized the recent measurements of five commonly-used phthalates in indoor environment in urban China and documented their distributions. Based on the activity patterns and exposure factors of Chinese population, Monte-Carlo simulation was used to derive their exposures. On average, the daily intake of all the targeted phthalates was 3.6 μg/kg/day for adults; and for children it ranged from 4.4 μg/kg/day to 8.1 μg/kg/day. For children, the total risk from exposures inside residences and offices was 32%-90% and 4%-19%, respectively. From commuting environments and other indoor environments, it was 5%-31%, and 3%-26%, respectively. For adults, the total risk from residences and offices was 26%-78% and 9%-35%. Additionally, from commuting environments and other indoor environments, it was 8%-35% and 5%-11%, respectively. The non-carcinogenic risk assessment was based on a cumulative Tolerable Daily Intake (TDI_cum), with means ranging from 0.18 to 0.41, which was mainly as a result of exposure to DiBP and DnBP. The means for lifetime cancer risk resulting from DEHP exposure ranged from 0.4 × 10^-6 to 2.0 × 10^-6 for urban population groups. For 80% of working adults and 40%-75%% of children, their cancer risks exceeded the EPA's benchmark (1.0 × 10^-6). The present study could provide important information for decision makers to reduce indoor phthalate exposures as well as the associated health risks for larger population groups in Chinese cities.

Differential occurrence, profiles and uptake of dust contaminants in the Barcelona urban area

Dust is a complex but increasingly used matrix to assess human exposure to organic contaminants both in indoor and outdoor environments. Knowledge concerning the effects of organic pollution towards health outcome is crucial. This study is aimed to determine the presence of legacy compounds (DDTs and polychlorinated biphenyls, PCBs), compounds used in recent times (organophosphorous flame retardants, organophosphorous pesticides, BPA, phthalates and alkylphenols) and compounds originated from combustion processes (polycyclic aromatic hydrocarbons, PAHs) as well as nicotine in indoor environments along the metropolitan area of Barcelona. Monitored sites include public areas with high turnout (high schools, museums samples) and libraries and private spaces (houses and cars). Almost all compounds (57 over the 59 targeted) were found in each dust sample and libraries and schools were the most contaminated, with concentrations of ∑phthalates and ∑OPFRs up to 15 and 10 mg g^-1, respectively. One-way ANOVA tests, Tukey contrasts and principal component analysis (PCA) revealed that sampling place influenced the observed contamination profiles and public and private environments were clearly differentiated. Finally, based on the concentrations detected, a deterministic calculation was performed to estimate the total daily intakes of each compound via dust. This information was used to evaluate the human exposure for toddlers, teenagers and adult workers. Consistently, the highest concentrations coming from plasticisers and flame retardants gave the major exposure rates. As expected, toddlers were the most affected group followed by museum and library workers, although the levels were below the reference doses.

Common SVOCs in house dust from urban dwellings with schoolchildren in six typical cities of China and associated non-dietary exposure and health risk assessment

This paper presents concentrations of common SVOCs in house dusts from urban dwellings with schoolchildren in six typical Chinese cities in winter and summer. Among the detected SVOCs, DBP and DEHP have a higher detection rate. The levels of these two substances contribute an average proportion of over 90% of the total SVOCs' levels, and show a significant correlation in most cities. Based on measured concentrations, schoolchildren's non-dietary exposures to DBP and DEHP at homes are estimated. Due to a longer time spent in child's bedrooms, children's non-dietary exposures to phthalates in child's bedrooms are greatly higher than that in living rooms. As for DBP non-dietary exposure, the most significant pathway is dermal absorption from air, accounting for >70%, whereas, the most predominant pathway for DEHP non-dietary exposure is dust ingestion, contributing from 61.5% to 91.9%. Based on estimated exposure doses, child-specific reproductive and cancer risk are assessed by comparing the exposure doses with DBP and DEHP benchmarks specified in California's Proposition 65. Owing to the high DBP exposure, nearly all of target schoolchildren appear to have a severe reproductive risk, although only non-dietary exposures at home are considered in this study. The average risk quotient of DBP exposure for child-specific MADL in all cities is 31.27 in winter and 10.35 in summer. Also, some schoolchildren are confronted with potential carcinogenic risk, because DEHP exposure exceeds child-specific NSRLs. The maximum DEHP exposure exceeds the cancer benchmark by over 6 times. These results also indicate that controlling indoor phthalates pollution at home is urgent to ensure the healthy development of children in China.

Concentration and factors affecting the distribution of phthalates in the air and dust: A global scenario

Phthalates are ubiquitously present environmental contaminants. Air and dust are the most important mediums of exposure to phthalates. The present study reviews the presence of phthalates in the air and dust reported from different countries in the last ten years (2007-2017). The phthalate concentrations revealed wide heterogeneity with a mean and median value 6 ± 19 μg/m³ and 0.5 μg/m³ respectively in the air and 1.5 × 10³ ± 2.2 × 10³ μg/g and 7.8x10²μg/g respectively in the dust. The highest phthalates levels in the air were reported from India (1.1 × 10² μg/m³) and in dust from Bulgaria (1.2 × 10⁴ μg/g). Overall higher levels were reported from developing countries as compared to developed countries. Di (2-ethylhexyl) phthalate (DEHP) and Di-n-butyl phthalate (DBP) were found to be predominant in both air and dust. Temperature, humidity, air exchange rate, building material and indoor maintenance were reported as the important factors influencing the levels of phthalates in the air and dust. In addition to policy level interventions, reducing the use of phthalate containing materials and controlling the factors which enhance the emission from existing sources can help in reducing human exposure to phthalates.

Urinary phthalate metabolites and environmental phenols in university students in South China

In China, university students have unique lifestyles compared with the rest of the youth population, as they are almost entirely isolated in campuses. The number of university students is large, and since students represent the future of human reproduction, exposure to environmental endocrine disruptors (EEDs) may have a large impact on society. In this study, levels of several EEDs, including phthalate metabolites, parabens, bisphenol A (BPA) and its analogues, triclosan (TCS), and benzophenone-3, were determined in 169 urine samples collected from university students in Guangzhou, South China. In addition, to further understand the potential sources of EEDs in their daily lives, a survey of students' lifestyles was conducted. Based on the urinary concentrations of EEDs and the survey results, daily exposure doses of target EEDs and their potential sources were investigated. Our results indicated that nine phthalate metabolites, three parabens, and BPA were ubiquitous (detection frequency > 60%) in the urine of university students. The concentrations of total phthalates (median: 99.4 µg L^-1) were orders of magnitude higher than those of total parabens (7.30 µg L^-1) and of other environmental phenols (0.40 µg L^-1). Significantly higher concentrations of phthalates, parabens, and TCS were found in female versus male students, partly due to the higher usage of personal care products (PCPs) by female students (p < 0.05). The estimated daily intakes (EDIs) of phthalates, parabens, BPA, and TCS were 0.46-1.35, 3.29-10.3, 0.007, and 0.67 µg/kg-bw/day, respectively. The EDIs of phthalates and BPA were much lower than those suggested by the European Food Safety guidelines (10, 50, and 50 µg/kg-bw/day for dibutyl phthalate, diethylhexyl phthalate, and BPA, respectively). Our results indicated that university students were widely exposed to EEDs, but at relatively low doses. PCP usage was the main reason for differences in levels of phthalates (especially diethyl phthalate) and parabens between male and female students in South Chinese universities.

Ventilation and Air Quality in Student Dormitories in China: A Case Study during Summer in Nanjing

The Air quality in student dormitories can have a major impact on the health of millions of students in China. This study aims to investigate the ventilation and air quality in student dormitories. Questionnaire survey was conducted in eight dormitory buildings and field measurements were conducted in one dormitory during the summer in Nanjing. The survey result reveals that most students thought the indoor and outdoor air quality was neutral and the correlation between indoor and outdoor perceived air quality is statistically significant. There are few indoor PM2.5 and ozone sources in dormitories and natural ventilation is the most common form of ventilation. However, there is no statistically significant correlation between window opening behaviors and the perceptions of indoor and outdoor air quality. The field measurement result shows the measured I/O ratios of PM2.5 and ozone over 37 days are in the range of 0.42⁻0.79 and 0.21⁻1.00, respectively. The I/O ratios for PM2.5 and ozone are 0.49 ± 0.05 and 0.26 ± 0.05 in the case of the window being closed, and the I/O ratios for PM2.5 and ozone are 0.65 ± 0.08 and 0.50 ± 0.15 in the case of the window being open. The outdoor and indoor ozone concentrations show pronounced diurnal periodic variations, while the PM2.5 concentrations do not. Finally, recommended open/close window strategies are discussed to reduce indoor pollutant levels. Understanding the indoor/outdoor PM2.5 and ozone concentrations in different window patterns can be a guidance to preventing high indoor PM2.5 and ozone exposure in student dormitories.

Dietary exposure to di-isobutyl phthalate increases urinary 5-methyl-2'-deoxycytidine level and affects reproductive function in adult male mice

Phthalates are a large family of ubiquitous environmental pollutants suspected of being endocrine disruptors. Epidemiological studies have associated phthalate metabolites with decreased reproductive parameters and linked phthalate exposure with the level of urinary 5-methyl-2'-deoxycytidine (5mdC, a product of methylated DNA). In this study, adult male mice were exposed to 450mg di-isobutyl phthalate (DiBP)/(kg·day) via dietary exposure for 28days. Mono-isobutyl phthalate (MiBP, the urinary metabolite) and reproductive function parameters were determined. The levels of 5mdC and 5-hydroxymethyl-2'-deoxycytidine (5hmdC) were measured in urine to evaluate if their contents were also altered by DiBP exposure in this animal model. Results showed that DiBP exposure led to a significant increase in the urinary 5mdC level and significant decreases in sperm concentration and motility in the epididymis, accompanied with reduced testosterone levels and down-regulation of the P450 cholesterol side-chain cleavage enzyme (P450scc) gene in the mice testes. Our findings indicated that exposure to DiBP increased the urinary 5mdC levels, which supported our recent epidemiological study about the associations of urinary 5mdC with phthalate exposure in the male human population. In addition, DiBP exposure impaired male reproductive function, possibly by disturbing testosterone levels; P450scc might be a major steroidogenic enzyme targeted by DiBP or other phthalates.