Urinary Monohydroxy Polycyclic Aromatic Hydrocarbons Research Articles

Antioxidant diet/lifestyle could mitigate the adverse impacts of urinary polycyclic aromatic hydrocarbons on lung function

BackgroundExtant research has demonstrated a correlation between exposure to polycyclic aromatic hydrocarbons (PAHs) and impaired lung function. The maintenance of an antioxidant-rich diet/lifestyle positively benefits pulmonary health. However, the potential ameliorative impact of an antioxidant-based diet/lifestyle on PAH-induced detrimental effects remains unclear. MethodsThe study drew upon cross-sectional data encompassing 1615 participants derived from the National Health and Nutrition Examination Survey 2007 to 2012. To gauge the maintenance of an antioxidant-rich diet/lifestyle, we employed Oxidative Balance Score (OBS) that incorporates sixteen nutrients and four lifestyle factors. Lung function was evaluated using percent-predicted Forced Vital Capacity (FVC), Forced Expiratory Volume 1st Second (FEV1), FEV1/FVC, and fractional exhaled nitric oxide (FENO). Our analytical approach entailed the utilization of weighted linear models. ResultsOur analysis unveiled interaction effects between urinary monohydroxy polycyclic aromatic hydrocarbons (OH-PAHs) and OBS concerning lung function. A one-unit increase in ∑OH-PAH (sum of eight OH-PAHs) was linked to a −0.75% reduction (95% CI: −1.28, −0.22) in FEV1/FVC. Individuals exhibiting low OBS displayed a marked decrease in FEV1/FVC (mean difference = −1.10%; 95% CI: −1.82, −0.39) for each unit increase in ∑OH-PAH, whereas no significant associations were discerned for those with medium or high OBS. Further stratification by gender yielded consistent results. The correlation between ∑OH-PAH and FENO proved statistically significant among participants with low OBS (P = 0.002) and medium OBS (P = 0.001), but non-significant for those with high OBS. Parallel findings emerged when examining percent-predicted FEV1 and FVC. ConclusionsIn conclusion, our study underscores the existence of statistically significant interactions between OH-PAHs and the maintenance of an antioxidant-rich diet and lifestyle concerning lung function. These findings underscore the pivotal role of maintaining an antioxidant-based diet and lifestyle in mitigating the adverse impacts of PAH exposure on lung function.

Does healthy lifestyle attenuate the detrimental effects of urinary polycyclic aromatic hydrocarbons on phenotypic aging? An analysis from NHANES 2001–2010

Existing evidence has showed that exposure to polycyclic aromatic hydrocarbons (PAHs) increases the risk of many chronic diseases. Given the close connection between aging (a major risk factor) and chronic diseases, however, very few studies have evaluated the association between PAHs and aging. Furthermore, whether modifiable healthy lifestyle could attenuate the detrimental effect of PAHs on aging remains unknown. Therefore, we conducted this study, aiming to: (1) examine the associations of urinary monohydroxy polycyclic aromatic hydrocarbons (OH-PAHs) and lifestyle with Phenotypic Age Acceleration (PhenoAge.Accel), a novel aging measure that captures morbidity and mortality risk; and (2) evaluate the potential interaction effects of OH-PAHs and lifestyle on PhenoAge.Accel. Cross-sectional data of 2,579 participants (aged 20–84 years, n = 1,292 females) from the National Health and Nutrition Examination Survey for years 2001–2010 were analyzed. A lifestyle index was constructed based on five components (drinking, smoking, body mass index, physical activity, and diet), ranging from 0 to 5. We calculated PhenoAge.Accel using algorithms developed previously. General linear regression models were used to examine the associations. We observed strong associations of OH-PAHs and lifestyle with PhenoAge.Accel. For instance, one unit increase in ∑NAP (sum of 1- and 2-hydroxynaphthalene) was associated with 0.37 year (95% confidence interval [CI]: 0.26, 0.48) increase in PhenoAge.Accel. We did not observe statistically significant interaction effects between OH-PAHs and lifestyle on PhenoAge.Accel. After stratified by sex, we observed strong associations as well as statistically significant interactions of OH-PAHs and lifestyle with PhenoAge.Accel among females. In conclusion, both OH-PAHs and lifestyle were independently associated with phenotypic aging and there were statistically significant interactions between OH-PAHs and lifestyle on phenotypic aging among females. The findings highlight the importance of adherence to a healthy lifestyle to attenuate the detrimental effects of exposures to PAHs on phenotypic aging among females.

Polycyclic aromatic hydrocarbons, long non-coding RNA expression, and DNA damage in coke oven workers.

Exposure to polycyclic aromatic hydrocarbons (PAHs) was associated with DNA damage, while the roles of long non-coding RNAs (lncRNAs) in the associations were unclear. We aimed to assess the association of lncRNA NR_024564 with urinary monohydroxy PAHs (OH-PAHs) and DNA damage among 332 coke oven workers. We determined 12 OH-PAHs by gas chromatography-mass spectrometry, and the expression level of NR_024564 by droplet digital RT-PCR and DNA damage by the comet assay. In total participants, we found that NR_024564 was not significantly associated with OH-PAHs or comet parameters. However, among workers with ≥ 20 working years, multiple OH-PAHs including urinary 1-hydroxyphenanthrene (1-OHPh), 2-OHPh, 3-OHPh, 9-OHPh, 1‑hydroxypyrene, and total PAH metabolites were related to increased comet parameters. Moreover, NR_024564 was significantly associated with 2-OHPh and four comet parameters. Each 1% increase in 2-OHPh was associated with 0.35% reduction (95% CI: 0.16%, 0.55%) in NR_024564 (P-FDR = 0.005), and 2-OHPh was marginally interacted with working years in relation to NR_024564 decrease. Also, each 1% increment of NR_024564 was related to 0.04-0.13% decrease of Olive tail moment, percent DNA in the comet tail, tail length, and tail moment (all P-FDR < 0.05). Furthermore, low NR_024564 level combined with high levels of 1-OHPh and 2-OHPh or ≥ 20 working years was positively associated with the comet parameters among the total participants. Our results indicated that NR_024564 might be linked to the adverse associations of PAHs with the DNA damage of coke oven workers who worked for ≥ 20years.

Associations between inhaled doses of PM2.5-bound polycyclic aromatic hydrocarbons and fractional exhaled nitric oxide

Exposure to fine particulate matter (PM2.5) is linked to various respiratory outcomes. However, the associations of concentrations of PM2.5-bound polycyclic aromatic hydrocarbons (PM2.5-bound PAHs) with airway inflammatory indices remains unclear. To assess effects of short-term exposure to PM2.5-bound PAHs on fractional exhaled nitric oxide (FeNO), we conducted a pilot study with repeated measures. We recruited 20 postgraduate students in Wuhan city, China, and repeatedly measured outdoor and indoor (including dormitories, offices and laboratories) PM2.5-bound PAHs concentrations, urinary monohydroxy polycyclic aromatic hydrocarbons (OH-PAHs) and FeNO levels in the four seasons. Subsequently, we estimated inhaled doses of PM2.5-bound PAHs based on the micro-environmental PM2.5-bound PAHs concentrations, time-activity patterns and referred inhalation rates. We assessed the association of inhaled doses of PM2.5-bound PAHs with FeNO using linear mixed-effects regression models. We found the positive associations of urinary ∑OH-PAHs levels with inhaled doses of indoor PM2.5-bound PAHs (including dormitories and offices) (all p < 0.05). A one-unit increase in inhaled doses of PM2.5-bound PAHs or in urinary concentrations of ∑OH-PAHs was corresponded to a maximum FeNO increase of 13.5% (95% CI: 5.4, 22.2) at lag2 day or of 6.8% (95% CI: 3.4, 10.2) at lag1 day. Inhaled doses of PM2.5-bound PAHs or urinary OH-PAHs was positively related to increased FeNO, they may be accepted as a short-term biomarker of exposure to PAHs in air. Exposure to PM2.5-bound PAHs in indoor air may contribute more to the body burden of PAHs than outdoor air, and exhibited stronger effect on increased FeNO rather than urinary OH-PAHs.

Environmental and lifestyle factors affecting exposure to polycyclic aromatic hydrocarbons in the general population in a Middle Eastern area

The aim of this study was to investigate environmental and lifestyle factors affecting exposure to PAHs in the general population in a large city of the Middle East (Tehran) by measuring urinary monohydroxy polycyclic aromatic hydrocarbons (OH-PAHs) and establishing relationships between PAHs exposure and related factors. Urine samples were collected from 222 randomly chosen subjects who were living in the urban area of Tehran, Iran. Subjects were required to complete a detailed questionnaire aimed to document their personal and sociodemographic information, activities, cooking-related appliances, smoking history/exposure, and consumed foodstuff. Identification and quantification of six OH-PAHs was carried out using a gas chromatography with mass spectrometry (GC-MS). The geometric means for 1-OHP, 1-NAP, 2-NAP, 2-FLU, 9-FLU, and 9-PHE for whole population study were 310, 1220, 3070, 530, 330, and 130 ng/g creatinine, respectively. The two naphthalene metabolites contributed on average 77% of the total concentration of six measured OH-PAHs, followed by the 2-FLU, 1-OHP, 9-FLU, and 9-PHE. The most important predictors of urinary PAHs were consumption of grilled/barbecued foods, smoking, and exposure to environmental tobacco smoking. Water pipe smoking was linked to urinary OH-PAH metabolite in a dose-response function. Residential traffic was also related with OH-PAH metabolite concentrations. Other factors including gender, age, exposure to common house insecticides, open burning, and candle burning were found to be statistically associated with the urinary levels of some OH-PAHs. High exposure to PAHs among general population in Middle Eastern large cities and its associated health implications calls for public health measures to reduce PAHs exposure.

Associations between urinary monohydroxy polycyclic aromatic hydrocarbons metabolites and Framingham Risk Score in Chinese adults with low lung function

Previous studies have reported an association of exposure to polycyclic aromatic hydrocarbons (PAHs) with lung function decline or cardiovascular diseases, or reduced lung function with 10-year cardiovascular (CV) risk. We analyzed risk factors for the 10-year Framingham CV risk using multiple logistic regression, and examined the mediational effect of reduced lung function on the association between exposure to PAHs and FRS using the post-exploratory structural equation modeling. Participants (n = 2268) were drawn from the Wuhan residents at baseline from the Wuhan-Zhuhai Cohort Study. They completed the physical examination, measurements of lung function and urinary monohydroxylated-PAHs (OH-PAHs). In all individuals, we found a dose-response relationship of PAHs exposure, forced expiratory volume in 1s (FEV1) or forced vital capacity (FVC) with the 10-year CV risk. The proportions of FEV1 and FVC mediation effects in association of PAH exposure with the10-year CV risk were 35% and 24%, respectively. The findings indicated that PAHs exposure or reduced lung function increased the 10-year CV risk. Impaired lung function may partly contribute to increase in the 10-year CV risk regarding exposure to PAHs.

Dose-response relationship between urinary polycyclic aromatic hydrocarbons metabolites and urinary 8-hydroxy-2′-deoxyguanosine in a Chinese general population

Association of exposure to polycyclic aromatic hydrocarbons (PAHs) with increased urinary 8-hydroxy-2′-deoxyguanosine (8-OHdG) formation has been reported in occupational population and children. However, studies on the association between them in general population are limited. A total of 1864 eligible subjects from the baseline Wuhan participants of the Wuhan-Zhuhai Cohort Study (n = 3053) were included in this study, after excluding individuals with certain disease and missing data on urinary monohydroxy PAHs (OH-PAHs) and 8-OHdG levels. Urinary monohydroxy PAHs and 8-OHdG levels were measured by gas chromatography-mass spectrometry and high performance liquid chromatography-electrochemical detection, respectively. Association of urinary OH-PAHs with urinary 8-OHdG was analyzed by multiple linear regression analysis. We found a dose-dependent relationship between urinary PAHs metabolites and urinary 8-OHdG (p < 0.05 for all). Furthermore, more evidence for the association of total concentrations of urinary OH-PAHs with 8-OHdG levels were observed in individuals with normal body mass index or central obesity (p < 0.01 for all). There was a dose-dependent relationship between urinary OH-PAHs levels and urinary 8-OHdG levels among a general Chinese population. Exposure to background PAHs may have a greater influence on urinary 8-OHdG levels in individuals with central obesity.

Association of polycyclic aromatic hydrocarbons metabolites and risk of diabetes in coke oven workers

Elevated polycyclic aromatic hydrocarbons (PAHs) metabolites have recently been linked to increased risk of diabetes in the general population, but little is known about the risk of diabetes due to high pollution levels of PAHs exposure. We aimed to examine whether occupational exposure to PAHs would be one of the important risk factors for diabetes in the coke oven workers. A total of 1472 coke oven workers with complete data were qualified for the present study. We measured 12 urinary monohydroxy polycyclic aromatic hydrocarbons (OH-PAHs) by gas chromatography–mass spectrometry (GC-MS). Multiple logistic regression was used to evaluate the associations between urinary OH-PAHs and risk of diabetes, with adjustment for the potential confounders. We found that elevated urinary 4-hydroxyphenanthrene (4-OHPh) was significantly associated, in a dose-dependent manner, with increased risk of diabetes (Ptrend = 0.003). Compared with individuals with 4-OHPh in the lowest quartile, the adjusted odds ratio (OR) of diabetes among those in the highest quartile was 2.80 (95% CI = 1.37–5.71). In stratified analysis, the association was more prominent in those who were smokers, overweight (BMI ≥24 kg/m2), with longer working years (≥20 years) and worked at coke oven settings. In addition, high levels of 4-OHPh combined with longer working years or overweight had a joint effect on the risk of diabetes. Our data suggested that elevated 4-OHPh was dose-responsive associated with increased risk of diabetes in the coke oven workers. The risk assessment of diabetes related to occupational PAHs exposure should take working years and BMI into consideration.

Inorganic-organic hybrid coating material for the online in-tube solid-phase microextraction of monohydroxy polycyclic aromatic hydrocarbons in urine.

An inorganic-organic hybrid nanocomposite (zinc oxide/polypyrrole) that represents a novel kind of coating for in-tube solid-phase microextraction is reported. The composite coating was prepared by a facile electrochemical polymerization strategy on the inner surface of a stainless-steel tube. Based on the coated tube, a novel online in-tube solid-phase microextraction with liquid chromatography and mass spectrometry method was developed and applied for the extraction of three monohydroxy polycyclic aromatic hydrocarbons in human urine. The coating displayed good extraction ability toward monohydroxy polycyclic aromatic hydrocarbons. In addition, long lifespan, excellent stability, and good compression resistance were also obtained for the coating. The experimental conditions affecting the extraction were optimized systematically. Under the optimal conditions, the limits of detection and quantification were in the range of 0.039-0.050 and 0.130-0.167 ng/mL, respectively. Good linearity (0.2-100 ng/mL) was obtained with correlation coefficients larger than 0.9967. The repeatability, expressed as relative standard deviation, ranged between 2.5% and 9.4%. The method offered the advantage of process simplicity, rapidity, automation, and sensitivity in the analysis of human urinary monohydroxy polycyclic aromatic hydrocarbons in two different cities of Hubei province. An acceptable recovery of monohydroxy polycyclic aromatic hydrocarbons (64-122%) represented the additional attractive features of the method in real urine analysis.

Magnetic graphene oxide as adsorbent for the determination of polycyclic aromatic hydrocarbon metabolites in human urine.

Detection of monohydroxy polycyclic aromatic hydrocarbons metabolites in urine is an advisable and valid method to assess human environmental exposure to polycyclic aromatic hydrocarbons. In this work, novel Fe3O4/graphene oxide composites were prepared and their application in the magnetic solid-phase extraction of monohydroxy polycyclic aromatic hydrocarbons in urine was investigated by coupling with liquid chromatography and mass spectrometry. In the hybrid material, superparamagnetic Fe3O4 nanoparticles provide fast separation to simplify the analytical process and graphene oxide provides a large functional surface for the adsorption. The prepared magnetic nanocomposites were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and vibrating sample magnetometry. The experimental conditions were optimized systematically. Under the optimal conditions, the recoveries of these compounds were in the range of 98.3-125.2%, the relative standard deviations ranged between 6.8 and 15.5%, and the limits of detection were in the range of 0.01-0.15 ng/mL. The simple, quick, and affordable method was successfully used in the analysis of human urinary monohydroxy polycyclic aromatic hydrocarbons in two different cities. The results indicated that the monohydroxy polycyclic aromatic hydrocarbons level in human urine can provide useful information for environmental exposure to polycyclic aromatic hydrocarbons.

Personal exposure levels of PAHs in the general population in northern rural area of Jiangsu Province, China

Polycyclic aromatic hydrocarbons (PAHs) are a group of compounds that are produced by incomplete combustion of organic matters. Studies in humans have shown associations between PAHs exposure and development of cancers. Urinary monohydroxy polycyclic aromatic hydrocarbons (OH-PAHs) are a class of PAH metabolites used as biomarkers for estimating human exposure to PAHs. We collected 332 urinary samples from a nonoccupational population in northern rural area of Jiangsu. Levels of 2-hydroxynathalene (2-OHN), 2-hydroxyfluorene (2-OHF) and 1-hydroxypyrene (1-OHP) were measured as biomarkers to assess body PAHs burdens. Three PAH metabolites were detected in more than 80% of urinary samples. After being adjusted with urinary creatinine concentration, the urinary concentrations were determined as 2-OHF > 1-OHP > 2-OHN in terms. The medians of 2-OHN, 2-OHF, 1-OHP for the general population were 1.74, 30.01, 25.24 μmoL/moL creatinine, respectively. The results demonstrated that nonoccupational populations in northern rural area of Jiangsu were exposed to extremely high PAHs. The urinary concentration (median and geometric mean) of 2-OHN,2-OHF,1-OHP in males (1.90, 0.37 ± 0.46; 34.90, 1.53 ± 0.41; 27.84, 1.52 ± 0.29 μmoL/moL creatinine, respectively) was slightly higher than in females (1.56, 0.32 ± 0.42; 29.60, 1.48 ± 0.40; 23.13, 1.49 ± 0.32 μmoL/moL creatinine, respectively). However, only 2-OHN was different significantly between males and females.

Erratum: Variability of urinary concentrations of polycyclic aromatic hydrocarbon metabolite in general population and comparison of spot, first-morning, and 24-h void sampling

Urinary mono-hydroxy polycyclic aromatic hydrocarbons (OH-PAHs) are commonly used in biomonitoring to assess exposure to polycyclic aromatic hydrocarbons (PAHs). Similar to other biologically non-persistent chemicals, OH-PAHs have relatively short biological half-lives (4.4–35 h). Little information is available on their variability in urinary concentrations over time in non-occupationally exposed subjects. This study was designed to (i) examine the variability of nine urinary OH-PAH metabolite concentrations over time and (ii) calculate sample size requirements for future epidemiological studies on the basis of spot urine, first-morning void, and 24-h void sampling. Individual urine samples (n=427) were collected during 1 week from 8 non-occupationally exposed adults. We recorded the time and volume of each urine excretion, dietary details, and driving activities of the participants. Within subjects, the coefficients of variation (CVs) for the wet-weight concentration of OH-PAHs in all samples ranged from 45% to 297%; creatinine adjustment reduced the CV to 19–288% (P<0.001; paired t-test). The simulated 24-h void concentrations were the least variable measure, with CVs ranging from 13% to 182% for the 9 OH-PAHs. Within-day variability contributed on average 84%, and between-day variability accounted for 16% of the total variance of 1-hydroxypyrene (1-PYR). Intraclass correlation coefficients of 1-PYR levels were 0.55 for spot urine samples, 0.60 for first-morning voids, and 0.76 for 24-h voids, indicating a high degree of correlation between urine measurements collected from the same subject over time. Sample size calculations were performed to estimate the number of subjects required for detecting differences in the geometric mean at a statistical power of 80% for spot urine, first-morning, and 24-h void sampling. These data will aid in the design of future studies of PAHs and possibly other biologically non-persistent chemicals and in the interpretation of their analytical results.

Association of urinary polycyclic aromatic hydrocarbons and serum C-reactive protein

The association of 9 urinary monohydroxy polycyclic aromatic hydrocarbons (OH-PAHs) with serum C-reactive protein (CRP) was investigated using the National Health and Nutrition Examination Survey (NHANES) 2003-2004. The unweighted number of participants included was 999, which represented 139,362,776 persons in the non-institutionalized US population. In adjusted logistic regressions, two OH-PAHs, 2-hydroxyphenanthrene and 9-hydroxyfluorene, were associated with elevated CRP (>3mg/l). Logistic regressions were adjusted for age, gender, race, exercise, body mass index, smoking status, diabetes, and hypertension. 2-Hydroxyphenanthrene >148ng/g creatinine had an odds ratio of 3.17 (95% CI 1.73-5.81) compared to 2-hydroxyphenanthrene < or =48ng/g creatinine, and 9-hydroxyfluorene >749ng/g creatinine had an odds ratio of 2.28 (95% CI 1.08-4.83) compared to 9-hydroxyfluorene < or =160ng/g creatinine. Intermediate levels of 2-hydroxyphenanthrene (49-148ng/g creatinine), and 9-hydroxyfluorene (161-749ng/g creatinine) were also significantly associated with elevated CRP compared to the respective reference categories. In a combined analysis, OH-PAHs were classified as low, medium, and high. Low OH-PAH was 2-hydroxyphenanthrene < or =48ng/g creatinine and 9-hydroxyfluorene < or =160ng/g creatinine. High OH-PAH was 2-hydroxyphenanthrene >148ng/g creatinine or 9-hydroxyfluorene >749ng/g creatinine. Participants not assigned to the low or high categories were classified as having medium OH-PAH concentrations. Compared to the low OH-PAH group, high OH-PAH had an odds ratio of 3.60 (95% CI 2.01-6.46) in an adjusted logistic regression. Given that inflammation (characterized here by CRP) is an important factor in the development of atherosclerosis and cardiovascular disease, these results suggest a role for OH-PAHs in the progression of atherosclerosis.

Variability of urinary concentrations of polycyclic aromatic hydrocarbon metabolite in general population and comparison of spot, first-morning, and 24-h void sampling

Urinary mono-hydroxy polycyclic aromatic hydrocarbons (OH-PAHs) are commonly used in biomonitoring to assess exposure to polycyclic aromatic hydrocarbons (PAHs). Similar to other biologically non-persistent chemicals, OH-PAHs have relatively short biological half-lives (4.4-35 h). Little information is available on their variability in urinary concentrations over time in non-occupationally exposed subjects. This study was designed to (i) examine the variability of nine urinary OH-PAH metabolite concentrations over time and (ii) calculate sample size requirements for future epidemiological studies on the basis of spot urine, first-morning void, and 24-h void sampling. Individual urine samples (n=427) were collected during 1 week from 8 non-occupationally exposed adults. We recorded the time and volume of each urine excretion, dietary details, and driving activities of the participants. Within subjects, the coefficients of variation (CVs) for the wet-weight concentration of OH-PAHs in all samples ranged from 45% to 297%; creatinine adjustment reduced the CV to 19-288% (P<0.001; paired t-test). The simulated 24-h void concentrations were the least variable measure, with CVs ranging from 13% to 182% for the 9 OH-PAHs. Within-day variability contributed on average 84%, and between-day variability accounted for 16% of the total variance of 1-hydroxypyrene (1-PYR). Intraclass correlation coefficients of 1-PYR levels were 0.55 for spot urine samples, 0.65 [corrected] for first-morning voids, and 0.77 [corrected] for 24-h voids, indicating a high degree of correlation between urine measurements collected from the same subject over time. Sample size calculations were performed to estimate the number of subjects required for detecting differences in the geometric mean at a statistical power of 80% for spot urine, first-morning, and 24-h void sampling. These data will aid in the design of future studies of PAHs and possibly other biologically non-persistent chemicals and in the interpretation of their analytical results.

Concentration and profile of 22 urinary polycyclic aromatic hydrocarbon metabolites in the US population

Urinary monohydroxy polycyclic aromatic hydrocarbons (OH-PAHs) are a class of PAH metabolites used as biomarkers for assessing human exposure to PAHs. The Centers for Disease Control and Prevention's National Health and Nutrition Examination Survey (NHANES) uses OH-PAHs to establish reference range concentrations for the US population, and to set benchmarks for future epidemiologic and biomonitoring studies. For the years 2001 and 2002, 22 OH-PAH metabolites were measured in urine specimens from 2748 NHANES participants. Percentages of samples with detectable levels ranged from nearly 100% for metabolites of naphthalene, fluorene, phenanthrene, and pyrene, to less than 5% for metabolites from parent compounds with higher molecular weight such as chrysene, benzo[ c]phenanthrene, and benz[ a]anthracene. The geometric mean for 1-hydroxypyrene (1-PYR)—the most commonly used biomarker for PAH exposure—was 49.6 ng/L urine, or 46.4 ng/g creatinine. Children (ages 6–11) generally had higher levels than did adolescents (ages 12–19) or adults (ages 20 and older). Model-adjusted, least-square geometric means for 1-PYR were 87, 53 and 43 ng/L for children, adolescents (ages 12–19) and adults (ages 20 years and older), respectively. Log-transformed concentrations for major detectable OH-PAHs were significantly correlated with each other. The correlation coefficients between 1-PYR and other metabolites ranging from 0.17 to 0.63 support the use of 1-PYR as a useful surrogate representing PAH exposure.