The effect of portable HEPA filter air cleaners on indoor PM2.5 concentrations and second hand tobacco smoke exposure among pregnant women in Ulaanbaatar, Mongolia: The UGAAR randomized controlled trial.

BACKGROUND: Portable HEPA filter air cleaners can reduce indoor fine particulate matter (PM2.5), but their use has not been adequately evaluated in high pollution settings. We assessed air cleaner effectiveness in reducing indoor residential PM2.5 and second hand smoke (SHS) exposures among non-smoking pregnant women in Ulaanbaatar, Mongolia. METHODS: We randomized 540 participants to an intervention group receiving 1 or 2 HEPA filter air cleaners or a control group receiving no air cleaners. We followed 259 intervention and 253 control participants to the end of pregnancy. We measured one-week indoor residential PM2.5 concentrations in early (~11weeks gestation) and late (~31weeks gestation) pregnancy and collected outdoor PM2.5 data from centrally-located government monitors. We assessed blood cadmium in late pregnancy. Hair nicotine was quantified in a subset (n=125) to evaluate blood cadmium as a biomarker of SHS exposure. We evaluated air cleaner effectiveness using mixed effects and multiple linear regression models and used stratified models and interaction terms to evaluate potential modifiers of effectiveness. RESULTS: The overall geometric mean (GM) one-week outdoor PM2.5 concentration was 47.9µg/m3 (95% CI: 44.6, 51.6µg/m3), with highest concentrations in winter (118.0µg/m3; 110.4, 126.2µg/m3). One-week indoor and outdoor PM2.5 concentrations were correlated (r=0.69). Indoor PM2.5 concentrations were 29% (21, 37%) lower in intervention versus control apartments, with GMs of 17.3µg/m3 (15.8, 18.8µg/m3) and 24.5µg/m3 (22.2, 27.0µg/m3), respectively. Air cleaner effectiveness was greater when air cleaners were first deployed (40%; 31, 48%) than after approximately five months of use (15%; 0, 27%). Blood cadmium concentrations were 14% (4, 23%) lower among intervention participants, likely due to reduced SHS exposure. CONCLUSIONS: Portable HEPA filter air cleaners can lower indoor PM2.5 concentrations and SHS exposures in highly polluted settings.

Prenatal exposure to PM10 and NO2 and children's neurodevelopment from birth to 24 months of age: mothers and Children's Environmental Health (MOCEH) study.

INTRODUCTION: Previous studies have suggested adverse effects of maternal exposure to air pollution on neurodevelopment in early childhood. OBJECTIVES: We aimed to investigate the association between prenatal exposure to particulates of less than 10 µm in diameter (PM10) and nitrogen dioxide (NO2) and neurodevelopment in children during the first 24 months of their lives. METHODS: The MOCEH study is a prospective birth cohort study in South Korea. Average exposure levels to PM10 and NO2 during the entire pregnancy were estimated using the inverse distance weighting (IDW) method. A total of 520 mother-child pairs who completed neurodevelopmental assessments using the Korean Bayley Scale of Infant Development II (K-BSID-II) more than once at ages of 6, 12 and 24 months were included. Mental developmental index (MDI) and psychomotor developmental index (PDI) from the K-BSID-II were used as outcome variables. RESULTS: There were negative associations between maternal exposure to PM10 and MDI (ß=-2.83; p=0.003) and PDI (ß=-3.00; p=0.002) throughout the first 24 months of life as determined by the generalized estimating equation (GEE) model. Maternal NO2 exposure was related with impairment of psychomotor development (ß=-1.30; p=0.05) but not with cognitive function (ß=-0.84; p=0.20). In a multiple linear regression model, there were significant effects of prenatal air pollution exposure on MDI (PM10: ß=-4.60; p<0.001, NO2: ß=-3.12; p<0.001) and PDI (PM10: ß=-7.24; p<0.001, NO2: ß=-3.01; p<0.001) at 6 months, but no significant association was found at 12 and 24 months of age. CONCLUSIONS: The findings suggest that exposure to air pollution may result in delayed neurodevelopment in early childhood.

Secondhand smoke exposure during pregnancy and infantile neurodevelopment.

During prenatal development, the nervous system may be more susceptible to environmental toxicants, such as secondhand smoke. The authors assessed the effects of prenatal and postnatal secondhand smoke exposure on the neurodevelopment of 6-month infants. The subjects were 414 mother and infant pairs with no medical problems, taken from the Mothers' and Children's Environmental Health study. Prenatal and postnatal exposures to secondhand smoke were determined using maternal self-reports. Examiners, unaware of exposure history, assessed the infants at 6 months of age using the Bayley Scales of Infant Development. Bayley scores were compared for secondhand smoke exposed and unexposed groups after adjusting for potential confounders. Multiple logistic regression analysis was carried out to estimate the risk of developmental delay posed by SHS exposure. The multivariate model included residential area, maternal age, pre-pregnancy body mass index, education, income, infant sex, parity, birth weight, and type of feeding. After adjusting for covariates, secondhand smoke exposure during pregnancy was found to be related to a decrease in mental developmental index score, but not to a decrease in psychomotor developmental index score. In addition, secondhand smoke exposure during pregnancy was found to increase the risk of developmental delay (mental developmental index score ≤85) at 6 months. This study suggests that the infants of non-smoking women exposed to secondhand smoke are at risk of neurodevelopmental delay.

Interaction between GSTM1/GSTT1 polymorphism and blood mercury on birth weight.

BACKGROUND: Mercury (Hg) is toxic to both the reproductive and nervous systems. In addition, glutathione S-transferases (GSTs), which conjugate glutathione to a variety of electrophilic compounds, are involved in the detoxification of Hg. OBJECTIVE: In this study we examined the association between prenatal exposure to Hg and birth weight as well as the influence of GST polymorphisms. METHODS: The total Hg concentration in maternal and cord blood was measured from 417 Korean women and newborns in the Mothers and Children's Environmental Health study from 2006 to 2008. Information on birth weight was collected from the patients' medical records. The genotyping of glutathione S-transferase M1 (GSTM1) and glutathione S-transferase T1 (GSTT1) polymorphisms was carried out using polymerase chain reaction. Regression analysis was performed to determine the association between the blood Hg concentration and birth weight in mothers with GSTM1 and GSTT1 polymorphisms. RESULTS: The geometric mean levels of Hg in the maternal blood during late pregnancy and in cord blood were 3.30 microg/L and 5.53 microg/L, respectively. For mothers with the GSTT1 null genotype, elevated Hg levels in maternal blood during late pregnancy were associated with an increased risk of lower birth weight. For mothers with both GSTM1 and GSTT1 null genotype, both maternal and cord blood Hg levels were associated with lower birth weight. CONCLUSIONS: This study suggests that the interactions of Hg with GSTM1 and GSTT1 polymorphisms play a role in reducing birth weight.

The Mothers and Children's Environmental Health (MOCEH) study.

The MOCEH study is a prospective hospital- and community-based cohort study designed to collect information related to environmental exposures (chemical, biological, nutritional, physical, and psychosocial) during pregnancy and childhood and to examine how exposure to environmental pollutants affects growth, development, and disease. The MOCEH network includes one coordinating center, four local centers responsible for recruiting pregnant women, and four evaluation centers (a nutrition center, bio-repository center, neurocognitive development center, and environment assessment center). At the local centers, trained nurses interview the participants to gather information regarding their demographic and socioeconomic characteristics, complications related to the current gestation period, health behaviors and environmental factors. These centers also collect samples of blood, placenta, urine, and breast milk. Environmental hygienists measure each participant's level of exposure to indoor and outdoor pollutants during the pre- and postnatal periods. The participants are followed up through delivery and until the child is 5 years of age. The MOCEH study plans to recruit 1,500 pregnant women between 2006 and 2010 and to perform follow-up studies on their children. We expect this study to provide evidence to support the hypothesis that the gestational environment has an effect on the development of diseases during adulthood. We also expect the study results to enable evaluation of latency and age-specific susceptibility to exposure to hazardous environmental pollutants, evaluation of growth retardation focused on environmental and genetic risk factors, selection of target environmental diseases in children, development of an environmental health index, and establishment of a national policy for improving the health of pregnant women and their children.

Oxidative stress and antioxidant defenses in asthmatic murine model exposed to printer emissions and environmental tobacco smoke.

Exposure to particulate emissions from printer and cigarette smoke affects the structure and function of mitochondria, which may account for the pathogenesis of respiratory diseases. The addition of charge for the pollutant aerosols may increase the toxicity by their deposition in the lower respiratory tract. The mitochondrial damage in the lung of asthmatic mice was assessed by examining the levels of reactive oxygen species (ROS), lipid peroxides, reduced glutathione, and the activities of isocitrate dehydrogenase, alpha-ketoglutarate dehydrogenase, succinate dehydrogenase, malate dehydrogenase, complexes I to IV, and cytochrome c. The oxidative phosphorylation (levels of adenosine triphosphatase) was evaluated for the assessment of mitochondrial functional capacity. We found highly significant elevated levels of ROS, lipid peroxides, and decreased levels of mitochondrial enzymes in the mice exposed to environmental tobacco smoke and printer emissions + environmental tobacco smoke (ETS). However, mice exposed to printer emissions alone exhibited slight significant variations in the parameters studied. From the results, we conclude that printer emissions exert a synergistic effect in the presence of ETS and induce intense damage to the lung mitochondria by disrupting the structural and functional integrity of the mitochondrial membrane.

Low blood levels of lead and mercury and symptoms of attention deficit hyperactivity in children: a report of the children's health and environment research (CHEER).

BACKGROUND: The goal of this study was to examine the association between low levels of lead and mercury in blood and symptoms of attention-deficit hyperactivity disorder (ADHD) among Korean children. METHODS: One thousand seven hundred and seventy eight children at 10 elementary schools in six South Korea cities participated in this study. Parents and guardians administered a questionnaire including Conners' parents rating ADHD scale to determine the presence of ADHD symptoms. In addition, clinical examinations of the children and determination of blood lead and mercury levels were included in the first Children's Health and Environment Research (CHEER) survey, which is now conducted annually in Korea. RESULTS: The risk for the appearance of ADHD symptoms was found to increase with the blood lead concentration. The mean blood lead concentration was low with a geometric mean of 1.8 microg/dl. The odds ratios (95% confidence intervals) for the presence of ADHD symptoms were 1.28 (0.57, 2.86), 1.32 (0.63, 2.74), 1.65 (0.77, 3.56), and 1.98 (0.76, 5.13) in children with blood lead levels of 1-<1.5, -<2.5, -<3.5, and >3.5 microg/dl, compared to those with blood lead levels of <1.0 microg/dl; these results statistically represented a borderline trend (p for trend: 0.07). The blood lead level showed a significant positive association with the Conners' ADHD score (beta=0.50, p<0.0001). However, the blood mercury levels were not found to be significantly associated with ADHD symptoms in children. The geometric mean mercury concentration in the blood was 2.4 microg/l. CONCLUSIONS: The observed association between blood lead concentration and the appearance of ADHD symptoms in Korean children suggests that lead, even at low concentrations, is a risk factor for ADHD.

Odor reduction rate in the confinement pig building by spraying various additives.

The objective of this on-site experiment was to evaluate and compare the effectiveness of currently utilized various additives, i.e. tap water, salt water, digested manure, microbial additive, soybean oil, artificial spice and essential oil, to reduce odor emissions from the confinement pig building. Odor reduction rates were evaluated with respect to sensual odor (odor concentration index, odor intensity and odor offensiveness) and odorous compounds (ammonia and sulfuric odorous compounds). Of the additives investigated in this study, salt water, artificial spice and essential oil had a positive effect on reducing odor generation. The effectiveness of salt water was only observed on ammonia, showing the reduction rates as a function of time (t=immediately, 1h, 3h, 5h, and 24h after spraying) were 0.1%, 20%, 36%, 11% and 0.2% as compared to initial level before spraying. The odor intensity and offensiveness were lessened by spraying artificial spice and essential oil of which maximum reduction rates ranged from 60% to 80%. Additionally, the essential oil had a significant effect on reducing sulfuric odorous compounds for 24h after spraying, which implicates that it functioned as not only a masking agent but also as an antimicrobial agent.

Effect of manual feeding on the level of farmer's exposure to airborne contaminants in the confinement nursery pig house.

The objective of the study is to demonstrate an effect of manual feeding on the level of farmer's exposure to airborne contaminants in the confinement nursery pig house. The levels of all the airborne contaminants besides respirable dust, total airborne fungi and ammonia were significantly higher in the treated nursery pig house with feeding than the control nursery pig house without feeding. Although there is no significant difference in respirable dust and total airborne fungi between the treatment and the control, their concentrations in the treated nursery pig house were also higher than the control nursery pig house. The result that the level of ammonia in the treated nursery pig house is lower than the control nursery pig house would be reasoned by the mechanism of ammonia generation in the pig house and adsorption property of ammonia to dust particles. In conclusion, manual feeding by farmer increased the exposure level of airborne contaminants compared to no feeding activity.

Spatial distribution of particulate matter (PM10 and PM2.5) in Seoul Metropolitan Subway stations.

The aims of this study are to examine the concentrations of PM10 and PM2.5 in areas within the Seoul Metropolitan Subway network and to provide fundamental data in order to protect respiratory health of subway workers and passengers from air pollutants. A total of 22 subway stations located on lines 1-4 were selected based on subway official's guidance. At these stations both subway worker areas (station offices, rest areas, ticket offices and driver compartments) and passengers areas (station precincts, subway carriages and platforms) were the sites used for measuring the levels of PM. The mean concentrations of PM10 and PM2.5 were relatively higher on platforms, inside subway carriages and in driver compartments than in the other areas monitored. The levels of PM10 and PM2.5 for station precincts and platforms exceeded the 24-h acceptable threshold limits of 150 microg/m3 for PM10 and 35 microg/m3 for PM2.5, which are regulated by the U.S. Environmental Protection Agency (EPA). However, levels measured in station and ticket offices fell below the respective threshold. The mean PM10 and PM2.5 concentrations on platforms located underground were significantly higher than those at ground level (p<0.05).

Effect of ventilation rate on gradient of aerial contaminants in the confinement pig building.

The principal aim of this study was to compare the aerial contaminants concentrations between the levels of ventilation rate and determine the variation pattern of aerial contaminants affected by the ventilation rate. As a result, there was not significant difference in total dust and total airborne microorganisms among three levels of ventilation rate (P>0.05) whereas the increased ventilation rate lowered the levels of respirable dust and gaseous compounds (P<0.05). Based on the results, it was concluded that the suspended gases in the confinement pig building generally followed the air streamline formed by the ventilation whereas the ventilation rate had little effect on the gradient of particulates, especially total dust, due to gravity generated by their size and weight. The findings that the concentrations of total airborne microorganisms were not also significantly different among the ventilation rates could be explained in terms of the fact that airborne microorganisms are easily adsorbed on the surface of dust particle.

Influence of extreme seasons on airborne pollutant levels in a pig-confinement building.

Understanding airborne pollutant levels in a pig-confinement building in seasons with extreme weather (ie, summer and winter) is important for managing air quality, which affects the health of farmers and others in the neighboring environment. The authors evaluated airborne pollutants-total dust, total airborne bacteria, and total airborne gram-negative bacteria-which had higher concentrations in summer than in winter, and concentrations of respirable dust, gaseous pollutants, and total airborne fungi, which were lower in summer than in winter. The authors found significant differences between summer and winter measurements for respirable dust and gaseous pollutants (p < .05). Total dust was positively correlated with bioaerosols and ammonia (p < .05), whereas respirable dust was positively correlated with odor concentration index (p < .05) and hydrogen sulfide (p < .01).

Facial anthropometric dimensions of Koreans and their associations with fit of quarter-mask respirators.

Past studies on respirator fit or performance have mostly been done for Whites or male subjects, and little attention has been paid to minorities and Asians. To fill this gap, this study was designed to provide facial anthropometric data for Koreans and to analyze the association between facial dimensions and respirator fit factors for three brands of quarter-mask respirators, two domestic and one imported brand, using a Portacount 8020. A total of 110 university student subjects, 70 males and 40 females volunteered for participation in the study. The results of this study showed that Korean males and females have different facial dimensions as compared with those of White males and females. Unexpectedly, the imported respirator performed better than the domestic respirators. Males were found to achieve better respirator fit than females regardless of respirator brands tested. The regression analysis found no common prognostic variables with the three respirator brands studied. A stepwise logistic regression analysis was conducted to find predictive facial dimensions with respirator fits. Some facial dimensions were found to be statistically significant, but these dimensions are different from the traditionally recommended facial dimensions of face length and lip width for quarter mask. To improve respirator fit for Koreans, these different facial characteristics need to be considered in the design of quarter mask respirators.

Level of silica in the respirable dust inhaled by dental technicians with demonstration of respirable symptoms.

Dental technicians are exposed to various dusts in working laboratories. This study was conducted to measure level of silica in the respirable dust generated from dental fixed prosthodontics manufacturing processes using Fourier Transform Infrared Spectroscopy (FTIR), and to compare their occurrence of respiratory symptoms with that of non-dental hospital workers (control group). Respirable dusts were personally sampled from dental technicians working at dental laboratories in Seoul Korea according to NIOSH Method 0600. Fifty personal samples were obtained during porcelain or polishing process and weighed by a gravimetric method. Concentration of respirable dust was 651 +/- 548 microg/m3 (Mean +/- SD) with highest concentration of 2,874 microg/m3 during the porcelain process and 725 +/- 414 microg/m3 with highest concentration of 1,764 microg/m3 during the polishing process. Concentration of silica was 6.51 +/- 6.07 microg/m3 with 18.85 microg/m3 highest and 14.88 +/- 11.21 microg/m3 with 50.98 microg/m3 highest for the porcelain and polishing process, respectively. Level of silica contents in the dust was 0.81% and 1.66% for the porcelain and polishing process, respectively. The level of silica contents and silica concentration were significantly different between the two processes. Comparing prevalence of respiratory symptoms between non-smoking seventeen dental technicians and thirty-five control workers, wheezing and rhinorrhea were significantly more manifested in the dental technicians than the controls. Total frequency of respiratory symptoms was also significantly higher in the dental technicians than the controls.