Luke P Naeher

Swiss Tropical and Public Health Institute, Bâle, Basel-City, Switzerland

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Publications (74)191.16 Total impact

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    ABSTRACT: ABSTRACT While evidence suggests associations between maternal exposure to air pollution and adverse birth outcomes, pregnant women's exposure to household air pollution in developing countries is understudied. Personal exposures of pregnant women (n = 100) in Trujillo, Peru to air pollutants and their indoor concentrations were measured. The effects of stove-use related characteristics and ambient air pollution on exposure were determined using mixed-effects models. Significant differences in 48-hr kitchen concentrations of particulate matter (PM2.5), carbon monoxide (CO), and nitrogen dioxide (NO2) concentrations were observed across fuel-types (p < 0.05). Geometric mean PM2.5 concentrations were 112 μg/m (3) (CLs: 52, 242 μg/m(3)) and 42 μg/m(3) (21, 82 μg/m(3)) in homes were wood and gas were used respectively. PM2.5 exposure was at levels which recent exposure-response analyses suggest may not result in substantial reduction in health risks even in homes where cleaner burning gas stoves were used.
    Archives of Environmental and Occupational Health 11/2013; · 1.19 Impact Factor
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    ABSTRACT: Nearly half of the world's population is exposed to household air pollution (HAP) due to long hours spent in close proximity to unvented cooking fires. We aimed to use PM2.5 and CO measurements to characterize exposure to cookstove generated woodsmoke in real time among control (n=10) and intervention (n=9) households in San Marcos, Cajamarca Region, Peru. Real time personal particulate matter with an aerodynamic diameter ≤2.5 µm (PM2.5), and personal and kitchen carbon monoxide (CO) samples were taken. Control households used a number of stoves including open fire and chimney stoves while intervention households used study-promoted chimney stoves. Measurements were categorized into lunch (9am - 1pm) and dinner (3pm - 7pm) periods, where applicable, to adjust for a wide range of sampling periods (2.8- 13.1hrs). During the 4-h time periods, mean personal PM2.5 exposures were correlated with personal CO exposures during lunch (r=0.67 p=0.024 n=11) and dinner (r=0.72 p=0.0011 n=17) in all study households. Personal PM2.5 exposures and kitchen CO concentrations were also correlated during lunch (r=0.76 p=0.018 n=9) and dinner (r=0.60 p=0.018 n=15). CO may be a useful indicator of PM during 4-h time scales measured in real time, particularly during high woodsmoke exposures, particularly during residential biomass cooking.
    Atmospheric Environment 11/2013; 79. · 3.11 Impact Factor
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    ABSTRACT: Nearly half of the world's population is exposed to household air pollution (HAP) due to long hours spent in close proximity to unvented cooking fires. The effect of woodsmoke exposure on oxidative stress was examined by investigating the association between woodsmoke exposure and biomarkers of DNA oxidation (8-hydroxy-2'-deoxyguanosine [8-OHdG]) and lipid peroxidation (8-isoprostane) among control and intervention stove users. HAP exposure assessment was conducted within the framework of a community-randomized controlled trial of 51 communities in San Marcos Province, Cajamarca Region, Peru. The first morning urine voids after 48h HAP exposure assessment from a subset of 45 control and 39 intervention stove users were analyzed for 8-OHdG and 8-isoprostane. General linear models and correlation analyses were performed. Urinary oxidative stress biomarkers ranged from 11.2 to 2270.0μg/g creatinine (median: 132.6μg/g creatinine) for 8-OHdG and from 0.1 to 4.5μg/g creatinine (median: 0.8μg/g creatinine) for 8-isoprostane among all study subjects (n=84). After controlling for the effects of traffic in the community and eating food exposed to fire among all subjects, cooking time was weakly, but positively associated with urinary 8-OHdG (r=0.29, p=0.01, n=80). Subjects' real-time personal CO exposures were negatively associated with 8-OHdG, particularly the maximum 30-second CO exposure during the sampling period (r=-0.32, p=0.001, n=73). 48h time integrated personal PM2.5 was negatively, but marginally associated with urinary 8-isoprostane (r=-0.21, p=0.09, n=69) after controlling for the effect of distance of homes to the road. Urinary 8-isoprostane levels reported in the available literature are comparable to results found in the current study. However there were relatively high levels of urinary 8-OHdG compared to data in the available literature for 8-OHdG excretion. Results suggest a sustained systemic oxidative stress among these Peruvian women chronically exposed to wood smoke.
    Environment international 09/2013; 60C:112-122. · 4.79 Impact Factor
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    ABSTRACT: Wildland firefighters are occupationally exposed to elevated levels of woodsmoke. Eighteen wildland firefighters were monitored for their personal exposure to particulate matter with median aerodynamic diameter of 2.5 microns (PM2.5), levoglucosan (LG), and carbon monoxide (CO) at 30 prescribed burns at the Savannah River Site, South Carolina. Linear mixed effect models were used to investigate the effect on exposure of various factors and to examine whether the firefighters were able to qualitatively estimate their own exposures. Exposure to PM2.5 and CO was higher when firefighters performed 'holding' tasks compared with 'lighting' duties, whereas exposures to CO and LG were higher when burns were in compartments with predominantly pine vegetation (P < 0.05). Exposures to PM2.5 (64-2068 µg m(-3)) and CO (0.02-8.2 p.p.m.) fell within the ranges observed in previous studies. Some recommended shorter term exposure limits for CO were exceeded in a few instances. The very low LG:PM2.5 ratios in some samples suggest that the exposures of wildland firefighters to pollutants at prescribed burns may be substantially impacted by non-woodsmoke sources. The association of the qualitative exposure estimation of the firefighters with actual PM2.5 and CO measurements (P < 0.01) indicates that qualitative estimation may be used to assess exposure in epidemiology studies.
    Annals of Occupational Hygiene 06/2013; · 2.16 Impact Factor
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    ABSTRACT: BACKGROUND: In developing countries, deficiencies in essential micronutrients are common, particularly in pregnant women. Although, biochemical indicators of diet and nutrition are useful to assess nutritional status, few studies have examined such indicators throughout pregnancy in women in developing countries. METHODS: The primary objective of this study was to assess the nutritional status of 78 Peruvian women throughout pregnancy for 16 different nutritional indicators including fat-soluble vitamins and carotenoids, iron-status indicators, and selenium. Venous blood samples from which serum was prepared were collected during trimesters one (n = 78), two (n = 65), three (n = 62), and at term via the umbilical cord (n = 52). Questionnaires were completed to determine the demographic characteristics of subjects. Linear mixed effects models were used to study the associations between each maternal indicator and the demographic characteristics. RESULTS: None of the women were vitamin A and E deficient at any stage of pregnancy and only 1/62 women (1.6%) was selenium deficient during the third trimester. However, 6.4%, 44% and 64% of women had ferritin levels indicative of iron deficiency during the first, second and third trimester, respectively. Statistically significant changes (p <= 0.05) throughout pregnancy were noted for 15/16 nutritional indicators for this Peruvian cohort, with little-to-no association with demographic characteristics. Three carotenoids (beta-carotene, beta-cryptoxanthin and trans-lycopene) were significantly associated with education status, while trans-lycopene was associated with age and beta-cryptoxanthin with SES (p < 0.05). Concentrations of retinol, tocopherol, beta-cryptoxanthin, lutein + zeaxanthin and selenium were lower in cord serum compared with maternal serum (p < 0.05). Conversely, levels of iron status indicators (ferritin, transferrin saturation and iron) were higher in cord serum (p < 0.05). CONCLUSION: The increasing prevalence of iron deficiency throughout pregnancy in these Peruvian women was expected. It was surprising though not to find deficiencies in other nutrients. The results highlight the importance of continual monitoring of women throughout pregnancy for iron deficiency which could be caused by increasing fetal needs and/or inadequate iron intake as pregnancy progresses.
    Nutrition Journal 06/2013; 12(1):80. · 2.65 Impact Factor
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    ABSTRACT: Wildland firefighters in the United States are occupationally exposed to high levels of woodsmoke. Results from experimental studies show that exposure to woodsmoke induces inflammation. A study was conducted to investigate the effect of occupational woodsmoke exposure on inflammatory biomarkers in firefighters working at prescribed burns. Twelve U.S. Forest Service wildland firefighters at the Savannah River Site, South Carolina, volunteered to give blood samples during four prescribed burns between February and March 2011. Twenty-four paired (pre- and post-work shift) blood samples were collected using dried blood spot method to facilitate repeated sample collection. Inflammatory biomarker concentrations in blood samples were measured using the Meso Scale Discovery multi-spot assay system. Concurrent personal PM(2.5) and CO monitoring of firefighters was conducted. Linear mixed models were used to test whether cross-work shift differences occurred in the following inflammatory biomarkers: IL-1β, IL-8, CRP, SAA, ICAM-1, and VCAM-1. IL-8 showed a significant cross-work shift difference as indicated by a post/pre-work shift ratio of 1.70 (95% CL: 1.35, 2.13; p = 0.0012). Concentrations of IL-8, CRP, and ICAM-1 increased in >50% of samples across work shift. Firefighters who lighted fires as opposed to other work tasks had the largest cross-work shift increase in IL-8. A significant cross-work shift increase in IL-8 in blood samples was observed in healthy wildland firefighters working at prescribed burns. Further research is needed to understand the physiological responses underlying the adverse effects of woodsmoke exposure, and the dose-response relationship between woodsmoke exposure and inflammatory responses.
    Journal of Occupational and Environmental Hygiene 04/2013; 10(4):173-80. · 1.28 Impact Factor
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    ABSTRACT: Household air pollution (HAP) from indoor burning of biomass or coal is a leading global cause of morbidity and mortality, mostly due to its association with acute respiratory infection in children, chronic respiratory and cardiovascular diseases in adults. Interventions that have significantly reduced exposure to HAP improve health outcomes and may reduce mortality. However, we lack robust, specific and field-ready biomarkers to identify populations at greatest risk, and to monitor the effectiveness of interventions. New scientific approaches are urgently needed to develop biomarkers of human exposure that accurately reflect exposure or effect. In this perspective, we describe the global need for such biomarkers, the aims of biomarker development, and the state of development of tests which have the potential for rapid transition from laboratory bench to field use.
    AJP Lung Cellular and Molecular Physiology 03/2013; · 3.52 Impact Factor
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    ABSTRACT: Although the production and use of some persistent organic pollutants (POPs) have been banned or highly restricted, human exposure remains a subject of investigation due to their environmental persistence. Physiological changes during pregnancy may affect the disposition of POPs in the mother's body, and thus fetal exposure. Changes in serum concentrations of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) across pregnancy trimesters, and trans-placental transfer to the fetus were investigated. Seventy-nine pregnant women in Trujillo, Peru were recruited in the first trimester of pregnancy, and provided blood samples for the analysis of 35 PCB congeners, 9 OCPs, and 11 polybrominated biphenyl diethers (PBDEs). Subsequently, maternal blood samples were collected in the second (n=64) and third trimesters (n=59), and cord blood samples (n=50) were collected at delivery. There were statistically significant changes across trimesters (p<0.05) for both fresh weight (increase) and lipid adjusted concentrations (decrease) of hexachlorobenzene (HCB), 2,2-Bis(4-chlorophenyl)-1,1-dichloroethene (p,p'-DDE), PCB-74, 118, 138-158, 153, 170, 180 and 194. Fresh weight concentrations of these POPs increased from first to third trimester by 10-28%. On the other hand lipid adjusted concentrations decreased from first to third trimester by 16-28%. Serum lipids increased from first to third trimester by 53% indicating the dilution of the POPs in the lipids. Concentrations of 2,2-Bis(4-chlorophenyl)-1,1,1-trichloroethane (p,p'-DDT), its metabolite p,p'-DDE, PCB-118, 138-158, 153, 170 and 180 above their limits of detection were measured in >60% of cord serum samples. Intra-individual correlations in maternal serum concentrations were high for most of the POPs (ρ=0.62-0.99; p<0.05) while correlations between maternal and cord serum concentrations were also high (ρ=0.68-0.99; p<0.05). Results indicate that the disposition in the body and blood concentrations of POPs may change during pregnancy, and show trans-placental transfer of DDT, DDE and PCBs.
    Chemosphere 02/2013; · 3.14 Impact Factor
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    ABSTRACT: Experimental studies indicate that exposure to woodsmoke could induce oxidative stress. However studies have not been conducted among the general population and specialized occupational groups despite the existence of elevated woodsmoke exposure situations. Therefore, we investigated whether there were across workshift changes in oxidative stress biomarkers among wildland firefighters who are occupationally exposed to elevated levels of woodsmoke. We collected pre- and post-workshift urine samples from 19 wildland firefighters before and after prescribed burns. We measured malondialdehyde (MDA) and 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxo-dG) in the samples, and analyzed whether there were cross-shift changes in their levels, and the relationships between the changes and the length of firefighting career, age of firefighter, and quantified workshift exposure to particulate matter. Overall no significant cross-shift change was observed for 8-oxodG or MDA in the urine samples of the firefighters. Changes in both biomarkers were also not associated with PM(2.5), which was used as a marker of exposure. However, overall unadjusted geometric mean 8-oxo-dG levels in the samples (31μg/g creatinine) was relatively higher compared to those measured in healthy individuals in many occupational or general population studies. Additionally, cross-shift changes in 8-oxo-dG excretion were dependent on the length of firefighting career (p=0.01) or age of the subject (p=0.01). Significant increases in 8-oxo-dG level from pre-shift to post-shift were observed for those who had been firefighters for 2years or less. The results indicate that oxidative stress response measured as cross-shift changes in 8-oxo-dG may depend on age or the length of a firefighter's career. These results suggest the need to investigate the longer term health effects of cumulative exposure of woodsmoke exposure among wildland firefighters, because increased body burden of oxidative stress is a risk factor for many diseases and is theorized to be involved in aging.
    Science of The Total Environment 02/2013; 449C:269-275. · 3.26 Impact Factor
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    ABSTRACT: Nearly half of the world's population depends on biomass fuels to meet domestic energy needs, producing high levels of pollutants responsible for substantial morbidity and mortality. We compare carbon monoxide (CO) and particulate matter (PM(2.5) ) exposures and kitchen concentrations in households with study promoted intervention (OPTIMA-improved) stoves and control stoves in San Marcos Province, Cajamarca Region, Peru. We determined 48hr indoor air concentration levels of CO and PM(2.5) in 93 kitchen environments and personal exposure, after OPTIMA-improved stoves had been installed for an average of seven months. PM(2.5) and CO measurements did not differ significantly between OPTIMA-improved stoves and control stoves. Although not statistically significant, a post-hoc stratification of OPTIMA-improved stoves by level of performance revealed mean PM(2.5) and CO levels of fully functional OPTIMA-improved stoves were 28% lower (n=20, PM(2.5,) 136μg/m(3) 95%CI 54-217) and 45% lower (n=25, CO, 3.2ppm, 95%CI 1.5-4.9) in the kitchen environment compared to the control stoves (n=34, PM(2.5) , 189μg/m(3) , 95%CI 116-261; n=44, CO, 5.8ppm, 95%CI 3.3-8-2). Likewise, although not statistically significant, personal exposures for OPTIMA-improved stoves were 43% and 167% lower for PM(2.5) (n=23) and CO (n=25) respectively. Stove maintenance and functionality level are factors worthy of consideration for future evaluations of stove interventions. © 2013 John Wiley & Sons A/S. Published by Blackwell Publishing Ltd.
    Indoor Air 01/2013; · 3.30 Impact Factor
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    ABSTRACT: Women and children in developing countries are often exposed to high levels of air pollution including polycyclic aromatic hydrocarbons (PAHs), which may negatively impact their health, due to household combustion of biomass fuel for cooking and heating. We compared creatinine adjusted hydroxy-PAH (OH-PAH) concentrations in pregnant women in Trujillo, Peru who cook with wood to levels measured in those who cook with kerosene, liquefied petroleum gas or a combination of fuels. Seventy-nine women were recruited for the study between May and July 2004 in the first trimester of their pregnancy. Urine samples were collected from the subjects in the first, second and third trimesters for OH-PAH analyses. The concentrations of the OH-PAHs were compared across the type of fuel used for cooking and pregnancy trimesters. The relationships between OH-PAHs levels in the first trimester and concurrently measured personal exposures to PM(2.5), carbon monoxide and nitrogen dioxide together with their indoor and outdoor air concentrations were also investigated. Women cooking with wood or kerosene had the highest creatinine adjusted OH-PAH concentrations compared with those using gas, coal briquette or a combination of fuels. Concentrations of creatinine adjusted 2-hydroxy-fluorene, 3-hydroxy-fluorene, 1-hydroxy-fluorene, 2-hydroxy-phenanthrene and 4-hydroxy-phenanthrene were significantly higher (p<0.05) in women who used wood or kerosene alone compared with women who used liquefied petroleum gas (LPG), coal briquette or a combination of fuels. An increase in the concentrations of creatinine adjusted 9-hydroxy-fluorene, 1-hydroxy-phenanthrene, 2-hydroxy-phenanthrene, 4-hydroxy-phenanthrene and 1-hydroxy-pyrene in the third trimesters was also observed. Weak positive correlation (Spearman correlation coefficient, ρ<0.4; p<0.05) was observed between all first trimester creatinine adjusted OH-PAHs and indoor (kitchen and living room), and personal 48-h TWA PM(2.5). Women who cooked exclusively with wood or kerosene had higher creatinine adjusted OH-PAH levels in their urine samples compared to women who cooked with LPG or coal briquette.
    Environment international 01/2013; 53C:1-8. · 4.79 Impact Factor
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    ABSTRACT: BACKGROUND/OBJECTIVE: A study was undertaken at the United States Department of Energy's Savannah River Site (SRS), Aiken, South Carolina to investigate radionuclide activity concentrations in litter and duff from select areas at SRS. Litter (i.e. vegetative debris) and duff (i.e. highly decomposed vegetative debris) can often be the major fuels consumed during prescribed burns and have potential to release radiological contaminants into the environment. METHODS: Repeated samples from 97 locations were collected systematically across SRS and analyzed for radionuclide activity. Radionuclide activity concentrations found in litter and duff were compared. As spatial trends were of interest, spatial distributions of radionuclide activity concentrations found in litter and duff and spatial dependency amongst the data were explored. RESULTS: (7)Be, (40)K, and (137)Cs showed statistically significant proportional differences between litter and duff samples. Duff sample concentrations for (137)Cs (p < 0.0001) and (40)K (p = 0.0015) were statistically higher compared to litter samples. (7)Be activity concentrations were statistically higher in litter as compared to duff (p < 0.0001). For (40)K litter and duff samples, spatial correlation tests were not significant at p = 0.05 and the maps did not indicate any apparent high concentrations centered near possible radionuclide sources (i.e. SRS facilities). For (7)Be litter samples, significant spatial correlation was calculated (p = 0.0085). No spatial correlation was evident in the (7)Be duff samples (p = 1.0000) probably due to small sample size (n = 7). (137)Cs litter and duff samples showed significant spatial correlations (p < 0.0001 and p < 0.0001, respectively). CONCLUSIONS: To date, few studies characterize radionuclide activity concentrations in litter and duff, and to our knowledge none present spatial analysis. Key findings show that across SRS, (137)Cs is the primary radionuclide of concern, with the highest number of samples reported above MDC in litter (51.4%) and duff samples (83.2%). However, (137)Cs litter and duff spatial trends in the maps generated from the kriging parameters do not appear to directly link the areas with higher activity concentrations with SRS facilities. The results found herein provide valuable baseline monitoring data for future studies of forest surface fuels and can be used to evaluate changes in radioactivity in surface fuels in the southeast region of the U.S.
    Journal of Environmental Management 12/2012; 115C:217-226. · 3.06 Impact Factor
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    ABSTRACT: Multiple air monitoring campaigns were conducted from 2003 to 2007 during the months of December through April in which time-integrated monitoring of PM2.5 was performed during 55 prescribed burn (PB) events administered under select meteorological conditions. The data were analyzed using a generalized additive mixed-model (GAMM) where the logarithm of PM2.5 concentrations were modeled as the sum of linear and non-linear functions of our covariates of interest after accounting for the confounding associated with the grouping structure of our data and spatial dependency. Our model explained 61% of the variance of log transformed PM2.5. The GAM component of the model (i.e. our covariates of interest) explained 40% of that variance and the mixed-model component (i.e. random-effects and spatial correlation) explained 21%. Within burn events, concentrations across our air monitoring grid were significantly influenced by the distance from burn perimeter to air monitor and the proportion of time the air monitor was in line with the wind field over the burn. Among burns, variation was significantly influenced by burn duration, burn size, mode of ignition, and regional background PM2.5; indicating the importance of these for fire management. Measures of burn intensity and meteorology were found to be insignificant in our model; however, it is possible that some of these effects were absorbed by the random-effects of our model. These findings demonstrate that downwind exposure is largely a function of wind direction combined with distance from the burn and that emissions from one burn to the next are dependent on burn size, duration, and mode of ignition.
    Atmospheric Environment 09/2012; 56:203–211. · 3.11 Impact Factor
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    ABSTRACT: The objective of this study was to assess the utility of urinary Clara cell protein (CC16) as a biomarker of increased lung epithelial permeability in non-smokers exposed to outdoor secondhand smoke. Twenty-eight healthy non-smoking adults visited outdoor patios of a restaurant and a bar where non-participants smoked and an open-air control with no smokers on three weekend days in a crossover study; subjects visited each site once for 3 h. Urine samples were collected at baseline, immediately post exposure and next morning, and analyzed for CC16. Changes in CC16 across location types or with cigarette count were analyzed using mixed-effect models, which included all subjects and stratified by gender. Urinary CC16 was higher in males (n=9) compared with females (n=18) at all measurement occasions (P<0.002), possibly reflecting prostatic contamination. Urinary CC16 from pre-exposure to post-exposure was higher following visits to restaurant and bar sites compared with the control among females but this increase did not reach statistical significance. Post-exposure to pre-exposure urinary CC16 ratios among females increased with cigarette count (P=0.048). Exposure-related increases in urinary CC16 were not seen among males. In conclusion, urinary CC16 may be a useful biomarker of increased lung epithelial permeability among female non-smokers; further work will be required to evaluate its applicability to males.Journal of Exposure Science and Environmental Epidemiology advance online publication, 18 July 2012; doi:10.1038/jes.2012.68.
    Journal of Exposure Science and Environmental Epidemiology 07/2012; · 3.19 Impact Factor
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    ABSTRACT: With an increase in indoor smoking bans, many smokers smoke outside establishments and near their entrances, which has become a public health concern. We characterized the exposure of nonsmokers to secondhand smoke (SHS) outside a restaurant and bar in Athens, Georgia, where indoor smoking is banned, using salivary cotinine and urinary 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL). In a crossover study, we assigned 28 participants to outdoor patios of a restaurant and a bar and an open-air site with no smokers on three weekend days; participants visited each site once and stayed for 3 hr. We collected saliva and urine samples immediately before and after the visits (postexposure) and on the following morning and analyzed samples for cotinine and total NNAL, respectively. Regression models were fitted and changes in biomarkers were contrasted between locations. Postexposure and preexposure geometric mean salivary cotinine concentrations differed by 0.115 ng/mL [95% confidence interval (CI): 0.105, 0.126)] and by 0.030 ng/mL (95% CI: 0.028, 0.031) for bar and restaurant visits, respectively. There were no significant post- and preexposure differences in cotinine levels after control site visits, and changes after bar and restaurant site visits were significantly different from changes after control site visits (p < 0.001). Results comparing next-day and preexposure salivary cotinine levels were similar. Next-day creatinine-corrected urinary NNAL concentrations also were higher than preexposure levels following bar and restaurant visits [1.858 pg/mg creatinine higher (95% CI: 0.897, 3.758) and 0.615 pg/mg creatinine higher (95% CI: 0.210, 1.761), respectively], and were significantly different from changes after the control visits (p = 0.005). Salivary cotinine and urinary NNAL increased significantly in nonsmokers after outdoor SHS exposure. Our findings indicate that such exposures may increase risks of health effects associated with tobacco carcinogens.
    Environmental Health Perspectives 04/2012; 120(7):1010-6. · 7.26 Impact Factor
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    ABSTRACT: Public transport vehicle drivers, especially in highly polluted or trafficked areas, are exposed to high levels of air pollutants. In this study, we assessed the influence of traffic on levels of hydroxy polycyclic aromatic hydrocarbons (OH-PAHs) in commercial bus drivers in Trujillo, Peru, by measuring the within-shift changes in the urinary whole weight and creatinine-corrected concentrations of the PAH metabolites. We measured personal PM(2.5) as a proxy of exposure to traffic emission. Urine samples were collected daily from two bus drivers and three minivan drivers in Trujillo, pre-, mid-, post-work shift and on days when the drivers were off work (total n = 144). Ten OH-PAH metabolites were measured in the urine samples. Drivers were also monitored for exposure to PM(2.5) (n = 41). Daily work shift (mean = 13.1 ± 1.3 hr) integrated PM(2.5) was measured in the breathing zones of the drivers for an average of 10.5 days per driver. The differences across shift in OH-PAH concentrations were not statistically significant except for urinary 2-hydroxyfluorene (2-FLU) (p = 0.04) and 4-hydroxyphenanthrene (4-PHE) (p = 0.01) and creatinine-corrected 4-hydroxyphenanthrene (p = 0.01). Correlation between pairs of hydroxy-PAHs (ρ = 0.50 to 0.93) were highest for mid-shift samples. Concentrations of PM(2.5) (geometric mean = 64 μg/m(3); 95% confidence limits = 52 μg/m(3), 78 μg/m(3)) is similar to those measured in many other studies of traffic exposure. There was significant change across work shift for concentrations of only two of the OH-PAHs (2-FLU and 4-PHE). Results indicate that the drivers may have had limited time for clearance of PAH exposure from the body between work shifts. Comparisons of the concentrations of creatinine-corrected hydroxy-PAH to those reported in other studies indicate that exposure of public transport drivers to PAH could be similar. By following the subjects over multiple days, this study gives an indication of appropriate exposure situations for the use of hydroxy-PAHs and will be beneficial in designing future occupational studies of PAH exposure.
    Journal of Occupational and Environmental Hygiene 04/2012; 9(4):217-29. · 1.28 Impact Factor
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    ABSTRACT: 90% of people residing in rural areas of less-developed countries rely on coal and biomass fuels for heating and cooking, leading to high exposures to the products of incomplete combustion. Three Andean communities within the Santiago de Chuco province of Peru received two different models of improved cookstoves. The impact of these stoves in reducing personal exposures and kitchen concentrations of fine particulate matter (PM(2.5)) and carbon monoxide (CO) was evaluated separately in 64 homes (32 with each stove model) using air monitoring equipment. In the community receiving stove 1, baseline aggregate 48-h personal exposure (n=27) and kitchen concentrations (n=26) of PM(2.5) were 116.4 and 207.3μg/m(3), respectively, and 48-h personal (n=25) and kitchen (n=25) CO levels were 1.2 and 3.6ppm. After introducing the new stove to this community, those exposures reduced to 68.4 and 84.7μg/m(3), and 0.4 and 0.8ppm, representing reductions of 41.3%, 59.2%, 69.6% and 77.7% respectively. In the two communities receiving stove 2, corresponding levels were 126.3μg/m(3) (n=18), 173.4μg/m(3) (n=19), 0.9ppm (n=19), and 2.6ppm (n=17) before the installation of the stoves, and they reduced to 58.3, 51.1μg/m(3) and 0.6, 1.0ppm. Overall, homes receiving stove 2 saw reductions of 53.8, 70.5, 25.8 and 63.6%. All values are statistically significant (p<0.05) with the exception of personal CO reductions in the stove 2 group. Both stoves markedly reduce both kitchen and personal levels of wood smoke exposure, which we believe has the potential to improve health and quality of life.
    Science of The Total Environment 03/2012; 420:54-64. · 3.26 Impact Factor
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    ABSTRACT: In this study we compare airborne radionuclide concentrations during prescribed burns at the Savannah River Site (SRS) and a sample of forests in the Southeastern United States. The spatial trends of airborne radionuclide concentrations from prescribed burn areas at SRS are also characterized. Total suspended particulate (TSP) samples were taken at three settings (subsequently termed burn sample populations): during prescribed burns at SRS (n = 34), on nonburn days at SRS (n = 12) and during prescribed burns at five offsite locations in the Southeastern United States (n = 2 per location). Mass concentrations of TSP were calculated and alpha, beta and gamma spectroscopy was performed to determine radionuclide activity concentrations. Spatial correlation in radionuclide concentration was assessed and ordinary kriging was used to create continuous surface maps across our study area. Median activity concentrations of natural radionuclides including ⁴°K, thorium and uranium isotopes (n = 34) were higher in samples from SRS prescribed fires (p < 0.02) compared to offsite locations (n = 10) and nonburn days (n = 12). Median gross beta activity was also higher at SRS (p < 0.0001). Median concentrations of anthropogenic radionuclides did not significantly differ among burn sample populations except for ²³⁸Pu (p = 0.0022) and {sup 239,240}Pu (p = 0.014) with median concentrations of 8.41 x 10⁻⁴ and 6.72 x 10⁻⁵ pCi m⁻³ at SRS compared to 1.55 x 10⁻⁴ and -7.07 x 10⁻⁶ pCi m⁻³ (nonburn days) and 1.46 x 10⁻⁴ and 2.78 x 10⁻⁶ pCi m³ (offsite burns) respectively. Results from our spatial analysis found that only ⁴°K demonstrated significant spatial correlation (X² = 15.48, p = 0.0004) and spatial trends do not appear to directly link areas with higher activity concentrations with SRS facilities.
    Atmospheric Environment (1967) 01/2012; 54(1):643-656.
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    ABSTRACT: Although decline in lung function across workshift has been observed in wildland firefighters, measurements have been restricted to days when they worked at fires. Consequently, such results could have been confounded by normal circadian variation associated with lung function. We investigated the across-shift changes in lung function of wildland firefighters, and the effect of cumulative exposure on lung function during the burn season. We measured forced vital capacity (FVC), forced expiratory volume in 1 second (FEV₁), forced expiratory flow from 25% to 75% of FVC (FEF₂₅₋₇₅), and peak expiratory flow (PEF) of wildland firefighters before and after their workshifts. In all, 501 pre-shift and 488 post-shift measurements were collected over 22 prescribed burn days and 43 non-burn days from 24 non-smoking wildland firefighters during the dormant winter burn seasons of 2003 and 2004. We compared changes in the spirometry measures across the workshift on burn days to those observed on non-burn days. We also assessed the effect of cumulative exposure during the burn season on the spirometry measures. There were no significant differences in the across workshift changes on burn days compared to those on non-burn days for all the spirometry measures. However, for a given point in time during the season, each additional day of exposure was estimated to be associated with declines of 24 ml in pre-shift FVC and 24 ml in pre-shift FEV₁ (p <0.01). Cumulative exposure to woodsmoke was associated with slight decrements in lung function among the wildland firefighters.
    Inhalation Toxicology 11/2011; 23(13):835-41. · 1.89 Impact Factor
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    ABSTRACT: In the study described in this article, the authors' objective was to measure particles < or = 2.5 microm in aerodynamic diameter (PM2.5) and carbon monoxide (CO) in outdoor waiting areas and patios of restaurants and bars in downtown Athens, Georgia, where indoor smoking is banned. The authors also wanted to investigate whether the measured concentrations are directly associated with the number of cigarettes lit in these settings. Real-time PM2.5 and CO were monitored on four summer weekend afternoons/evenings in outdoor waiting areas or patios at five locations in Athens. In addition, smokers and pedestrians present or passing and motorized vehicles passing each sampling location were counted. PM2.5 levels were significantly higher than levels at the control location (all p-values > .001). Carbon monoxide levels outside the restaurant and bar sites did not differ significantly from the control. The results of the authors' study indicate that (1) secondhand smoke (SHS) leads to significant increases in PM2.5 outside of restaurants and bars; and (2) although CO can be used as a proxy for SHS in these outdoor environments, its levels remain relatively low.
    Journal of environmental health 10/2011; 74(3):8-17. · 1.01 Impact Factor

Publication Stats

868 Citations
191.16 Total Impact Points


  • 2013
    • Swiss Tropical and Public Health Institute
      Bâle, Basel-City, Switzerland
  • 2002–2013
    • University of Georgia
      • Department of Environmental Health Science
      Athens, GA, United States
    • University of California, Los Angeles
      • School of Public Health
      Los Angeles, CA, United States
  • 2003–2011
    • Centers for Disease Control and Prevention
      • • Division of Environmental Hazards & Health Effects
      • • Division of Laboratory Sciences
      Atlanta, Michigan, United States
  • 2010
    • University of Washington Seattle
      • Department of Environmental and Occupational Health Sciences
      Seattle, WA, United States
  • 2006
    • Yale University
      New Haven, Connecticut, United States
    • University of Rochester
      • Department of Environmental Medicine
      Rochester, NY, United States
  • 2005
    • University of California, Irvine
      Irvine, California, United States
  • 2000–2001
    • Malawi Centers of Disease Control and Prevention
      Lilongwe, Central Region, Malawi
  • 1999–2000
    • Yale-New Haven Hospital
      New Haven, Connecticut, United States