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Particulate matter (PM) exposure during pregnancy increases the risk of developing asthma in children. However, the placental mechanisms have yet to be elucidated. This study aims to evaluate the mechanisms associated with PM exposure during pregnancy and asthma susceptibility via placental epigenetic dysregulation. We analyzed data from two independent Korean birth cohorts (COCOA, 684 children; PSKC, 818 children). Physician-diagnosed current asthma and bronchial hyperresponsiveness (BHR) via methacholine challenge tests were evaluated at age seven. We estimated PM exposure with a diameter <10 μm (PM 10 ) during pregnancy using land-use regression models. We performed genome-wide methylation profiling in the placenta of 40 samples in the COCOA study and analyzed the gene expression levels. High PM 10 exposure during pregnancy increased the risk of developing current asthma and BHR in the COCOA study (aOR 2.36, 95% CI 1.06-5.22; aOR 2.14, 95% CI 1.40-3.27, respectively) and current asthma in the PSKC (aOR 2.62, 95% CI 1.35-5.09). The genes involved in neuronal differentiation and proliferation and Notch signaling pathways were significantly hypermethylated in children with high PM 10 -exposed asthma. The methylation and expression levels of eight genes (PAX6, REST, OLIG2, GLI1, ZBTB7A, NOTCH4, NOTCH1, and NOTCH3) in these pathways correlated with clinical parameters. This may effectively predict PM-related asthma through a prediction model using degrees of gene-based or CpG-based methylation (AUC = 0.96 and 0.93, respectively). PM 10 exposure during pregnancy impacts asthma development in offspring via placental DNA hypermethylation via neuronal differentiation and proliferation and Notch signaling pathways., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

This study aimed to investigate the short-term effect of exposure to indoor fine particulate matter (PM 2.5 ) on atopic dermatitis (AD) symptoms in children. Sixty-four children (40 boys and 24 girls) with moderate-to-severe AD, aged under 18 years were enrolled in the study. They were followed up from February 2019 through November 2020. Exposure to indoor PM 2.5 in each household of the enrolled children and their AD symptoms were measured daily. The generalized linear mixed model was utilized for statistical analysis. Subdivision analysis was performed by stratifying the patients by age, sex, season, severity, the presence of family allergic diseases, sensitization, and indoor environment conditions including temperature and relative humidity. A total of 9,321 person-days of AD symptom data were collected. The average PM 2.5 concentration was 28.7 ± 24.3 µg/m 3 , with the highest value in winter (47.1 ± 29.6 µg/m 3 ). The overall effect of PM 2.5 on AD symptoms was not statistically significant. However, an increase of 10 µg/m 3 in indoor PM 2.5 concentration increased AD symptom scores by 16.5% (95% CI: 6.5, 27.5) in spring and12.6% (95% CI: 4.3, 21.5) in winter, 6.7% (95% CI: 2.3, 11.3) at indoor temperatures of <25.5 °C, and by 15.0% (95% CI: 3.5, 27.7) with no use of an air purifier. The harmful effect of PM 2.5 in boys, in children aged ≥6 years, and in children with inhalant allergen sensitization was significant, showing an increase in AD symptoms of 4.9% (95% CI: 1.4, 8.6), 12.0% (95% CI: 5.3, 19.1), and 7.0% (95% CI: 1.9, 12.3) per 10 µg/m 3 of PM 2.5 , respectively. Furthermore, children with inhalant allergen sensitization plus severe symptoms (SCORing Atopic Dermatitis, SCORAD ≥ 30.7, median value) showed more harmful effects from exposure to PM 2.5 (15.7% (95% CI: 4.5, 28.1) increase in AD symptom scores per 10 µg/m 3 of PM 2.5 increase). Indoor exposure to PM 2.5 exacerbated AD symptoms in children in spring, winter, and at indoor temperatures of < 25.5 °C. In particular, this harmful effect was prominent in children with inhalant allergen sensitization and severe symptoms. Minimizing exposure to indoor PM 2.5 is needed for the proper management of AD.

Prenatal particulate matter <2.5 μm (PM 2.5 ) is associated with adverse birth growth. However, the longitudinal growth impacts have been little studied, and no mechanistic relationships have been described. We investigated the association between prenatal PM 2.5 exposure and growth trajectories, and the possible role of epigenetics. We enrolled 1313 neonates with PM 2.5 data measured by ordinary kriging from the COhort for Childhood Origin of Asthma and allergic diseases, followed up at 1, 3, and 5 years to evaluate growth. Differential DNA methylation and pyrosequencing of cord blood leukocytes was evaluated according to the prenatal PM 2.5 levels and birth weight (BW). PM 2.5 exposure during the second trimester (T2) caused the lowest BW in both sexes, further adjusted for indoor PM 2.5 levels [female, aOR 1.39 (95% CI 1.05-1.83); male, aOR 1.36 (95% CI 1.04-1.79)]. Bayesian distributed lag models with indoor PM 2.5 adjustments revealed a sensitive window for BW effects at 10-26 weeks gestation, but only in females. Latent class mixture models indicated that a persistently low weight-for-height percentile trajectory was more prevalent in the highest PM 2.5 exposure quartile at T2 in females, compared to a persistently high trajectory (36.5% vs. 20.3%, P = 0.022). Also, in the females only, the high PM 2.5 and low BW neonates showed significantly greater ARRDC3 methylation changes. ARRDC3 methylation was also higher only in females with low weight at 5 years of age. Higher fetal PM 2.5 exposure during T2 may cause a decreased growth trajectory, especially in females, mediated by ARRDC3 hyper-methylation-associated energy metabolism., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Background: Air pollution is associated with depressive and anxiety symptoms in the general population. However, this relationship among pregnant women remains largely unknown., Objective: To evaluate the association between pregnancy air pollution exposure and maternal depressive and anxiety symptoms during the third trimester assessed using the Center for Epidemiologic Studies-Depression and State-Trait Anxiety Inventory scales, respectively., Methods: We analyzed 1481 pregnant women from a cohort study in Seoul. Maternal exposure to particulate matter with an aerodynamic diameter <2.5 μm (PM 2.5 ) and <10 μm (PM 10 ), as well as to nitrogen dioxide (NO 2 ) and ozone (O 3 ) for each trimester and the entire pregnancy was assessed at participant's residential address by land use regression models. We estimated the relative risk (RR) and corresponding confidence interval (CI) of the depressive and anxiety symptoms associated with an interquartile range (IQR) increase in PM 2.5 , PM 10 , NO 2 , and O 3 using modified Poisson regression., Results: In single-pollutant models, an IQR increase in PM 2.5 , PM 10 , and NO 2 during the second trimester was associated with an increased risk of depressive symptoms (PM 2.5 RR = 1.15, 95% CI: 1.04, 1.27; PM 10 RR = 1.13, 95% CI: 1.04, 1.23; NO 2 RR = 1.15, 95% CI: 1.03, 1.29) after adjusting for relevant covariates. Similarly, an IQR increase in O 3 during the third trimester was associated with an increased risk of depressive symptoms (RR = 1.09, 95% CI: 1.01, 1.18), while the IQR increase in O 3 during the first trimester was associated with a decreased risk (RR = 0.89, 95% CI: 0.82, 0.96). Exposure to PM 2.5 , PM 10 , and NO 2 during the second trimester was significantly associated with anxiety symptoms. The associations with PM 2.5 and O 3 in single-and multi-pollutant models were consistent., Conclusions: Our findings indicate that increased levels of particulate matter, NO 2 , and O 3 during pregnancy may elevate the risk of depression or anxiety in pregnant women., (Copyright © 2021 The Authors. Published by Elsevier GmbH.. All rights reserved.)

Background: An association between maternal exposure to air pollution and the birth weight distribution has been reported, but the extent to which this relationship varies according to socioeconomic status (SES) is unknown. This study examined the relationship using the data from a Korean birth cohort., Methods: Data for singleton births in Seoul from 2007 to 2017 (n = 1739) were analyzed. Maternal exposures to particulate matter with an aerodynamic diameter <10 µm (PM 10 ) and <2.5 µm (PM 2.5 ), as well as to nitrogen dioxide (NO 2 ) and ozone (O 3 ) for each trimester and the entire pregnancy were estimated using residential address, gestational age, and the birth date. The associations between the interquartile range (IQR) increases in pollutant concentrations and the changes in birth weight were examined using linear regression and quantile regression models. The socioeconomic disparities in the associations were investigated using a derived SES variable based on the composite of parental education and occupation. This SES variable was then interacted with the air pollutant., Results: In the gestational age-adjusted models, particulate air pollutants (PM 10 and PM 2.5 ) and O 3 were associated with birth weight decreases for the lower birth weight percentiles. For example, the decrease in mean birthweight per IQR increase in PM 2.5 during second trimester was -21.1 g (95% confidence interval (CI) = -41.8, -0.4), whereas the quantile-specific associations were: 10th percentile -27.0 g (95% CI = -46.6, -7.3); 50th percentile -22.2 g (95% CI = -39.6, -4.8); and 90th percentile -22.9 g (95% CI = -45.5, -0.2). Particulate air pollutants and O 3 showed a pattern of socioeconomic inequalities; the reduced birth weight was of greater magnitude for children from a low SES group., Conclusions: Negative associations between particulate air pollutants and O 3 and birth weight were consistently greater at the lower quantiles of the birth weight distribution, especially in lower SES group., Competing Interests: Declaration of Competing Interest The authors declare no conflicts of interest., (Copyright © 2020 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Objectives: To investigate the association between particulate matter with an aerodynamic diameter of less than 2.5 μm (PM 2.5 ) exposure during each trimester of pregnancy and development of lower respiratory tract infections (LRTIs) during the first 3 years of life and whether GSTM1 gene polymorphisms modify these effects., Methods: This study included 1,180 mother-child pairs from the Cohort for Childhood Origin of Asthma and allergic diseases. The PM 2.5 levels during pregnancy were estimated by residential address using land-use regression models based on a national monitoring system. A diagnosis of LRTIs was based on a parental report of a physician's diagnosis. Real-time polymerase chain reaction was used for GSTM1 genotyping., Results: Higher PM 2.5 exposure during the third trimester was associated with LRTIs at 1 year of age (aRR, 1.06; 95% CI, 1.00-1.13). This result did not change after adjusting for PM 2.5 exposures during the first and second trimesters (aRR, 1.06; 95% CI, 0.99-1.13). This association was significant after adjusting for PM 2.5 exposures during first year of age (aRR, 1.08; 95% CI, 1.02-1.15) and exposures to NO 2 and ozone at the third trimester (aRR, 1.07; 95% CI, 1.00-1.16). In addition, PM 2.5 exposure during the third trimester increased the risk of LRTIs at 1 year of age in cases with the GSTM1 null genotype (aRR, 1.26; 95% CI, 1.01-1.57; P for interaction .20)., Conclusion: Higher PM 2.5 exposure during the third trimester of pregnancy may increase the susceptibility to LRTIs at 1 year of age. This effect is modified by GSTM1 gene polymorphisms., (© 2019 Wiley Periodicals, Inc.)

Background: Exposure to air pollution aggravates symptoms of atopic dermatitis (AD) in children in the population studies. Variability in individual patient's response from individual susceptibility is needed to be explored., Objective: This study aimed to investigate spectrum of individual variability in the associations between AD symptoms and air quality., Methods: We enrolled 89 children aged 0-6 years with AD (22 890 person-days). Daily manifestation of symptoms was recorded for an average of 257 days (range 100-499). Both an individual analysis using logistic regression models and an overall analysis using a generalized estimating equation were performed., Results: The odds ratios of an individual ranged 0.24-8.11 for particulate matter <10 μm in diameter (PM 10 ), 0.09-101.92 for nitrogen oxide (NO 2 ), 0.03-44.00 for ozone (O 3 ), 0.11-58.30 for sulfur dioxide (SO 2 ), 0.00-15.83 for carbon monoxide (CO), 0.00-39 446.94 for temperature, and 0.03-5.18 for relative humidity, demonstrating a wide individual variability. In the overall analysis, PM 10 , NO 2 , SO 2 , and CO had a significantly positive association, whereas temperature and relative humidity were negatively associated with AD symptoms. Air pollution was responsible for aggravation of symptoms from 24.7% (O 3 ) to 39.3% (SO 2 ) of AD children. Overall, 71.9% of the AD children responded to at least one or more air pollution and weather variable., Conclusion: Responses of AD children to air pollution and weather variable were considerably variable among individuals. An individualized model would be useful to forecast and manage AD symptoms in patients., (© 2018 EAACI and John Wiley and Sons A/S. Published by John Wiley and Sons Ltd.)

The effects of weather and air pollution on atopic dermatitis (AD) flares have not been well investigated. To investigate the effects of particulate matter (PM) on AD symptoms by weather type, a total of 125 young children (76 boys and 49 girls) under 6 years of age with AD living in Seoul, Korea, were enrolled as a panel and followed for 17 months between August 2013 and December 2014. AD symptoms were recorded on a daily basis, including itching, sleep disturbance, erythema, dry skin, oozing, and edema. Daily weather was classified into 7 categories according to spatial synoptic classification (SSC). Personal exposure to PM with an aerodynamic diameter less than 2.5 and 10 μm (PM 2.5 and PM 10 , respectively) in each individual was estimated with time-weighted average concentrations considering outdoor and indoor levels of PMs and time to spend outdoors or indoors in a day. Generalized linear mixed models were used to analyze the effects of PM 2.5 and PM 10 on AD symptoms, controlling for ambient temperature, humidity, age, sex, SCORAD (SCORing of AD) at enrollment, fever, day of week, and topical corticosteroid use. A total of 20,168 person-days of symptom records were collected. The presence of AD symptoms was higher on dry polar (DP) days (45.4%, P < .0001) than on moist tropical (MT) days (37.7%, P < .0001). Overall, the risk of AD symptoms significantly increased with increased exposure to PM 2.5 and PM 10 . Among the 7 weather types, the risks of AD symptoms caused by PM 2.5 and PM 10 exposure were significantly increased on dry moderate (DM) days, while not significant on the other weather types. In addition, lagged effect of PM 2.5 up to 4 days was found on DM days. In conclusion, dry moderate weather type, particulate matters, and their modifying effects should be simultaneously considered for proper management of AD., (Copyright © 2018. Published by Elsevier GmbH.)

Introduction: Increased exposure to particulate matter (PM) appears to increase the development of atopic diseases and allergic sensitization. This study evaluated the association between daily levels of PM with diameters less than 10µm (PM10) and PM2.5 and symptoms of atopic dermatitis (AD) in children living in an industrial urban area., Methods: Indoor PM10 and PM2.5 concentrations were measured with an optical particle counter in two preschools near large industrial complexes in Ulsan, South Korea during two 6-month periods (May-October of 2012 and 2013). Twenty-one children with AD from these preschools were enrolled and observed daily for AD symptoms during the same periods. Indoor and outdoor PM concentrations were used to estimate PM exposure based on time activity patterns., Results: Analysis of PM10 and PM2.5 concentrations showed that indoor and outdoor PM10 levels varied similarly throughout each 6-month period. In addition, indoor concentration of PM2.5 had high correlation with ambient outdoor concentration of PM10. Correlation analysis also indicated a significant positive correlation between the exacerbation of AD symptoms and daily mean exposure to PM10 and PM2.5. Based on a generalized linear mixed model (GLMM), PM exposure was significantly associated with the exacerbation of AD symptoms, with a maximum adjusted odds ratio (aOR) of 1.399 for a 10µg/m 3 increase of PM2.5 (95% CI: 1.216-1.610)., Discussion: Our findings suggest that short-term exposure to PM can exacerbate AD in young children living in an industrial urban area. PM2.5 had a stronger effect than PM10 on exacerbation of AD symptoms., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Most of researches on the impact of indoor air pollutants on atopic dermatitis (AD) have been based upon animal models, in vitro experiments and case-control studies. However, human data to elucidate the role of indoor air pollution on worsening symptoms of pre-existing AD from a longitudinal study are scarce. The objective of this prospective study was to evaluate the effect of indoor air pollution on AD symptoms in children. We surveyed 30 children with AD in a day-care centre, which moved to a new building during the study. These children stayed there for 8 hours a day Monday through Friday, and their daily symptom scores were recorded. Indoor and outdoor air pollutant levels were continuously measured 24 hours a day for 12 months (Period 1 to 4). Data were analyzed using a generalized linear mixed model. Compared to the period before moving (Period 1), concentrations of indoor air pollutants mostly increased after moving (Period 2) and decreased by natural ventilation and bake-out (Periods 3 and 4). The rate of positive AD symptom increased from 32.8% (Period 1) up to 43.8% (Period 2) and 50.5% (Period 3), then decreased to 35.4% in Period 4 (P < 0.0001). When the delayed effects of indoor air pollutants on AD symptoms 2 days later were evaluated, AD symptoms significantly increased by 12.7% (95% CI: -0.01 to 27.1) as toluene levels increased by 1 ppb (P = 0.05). In conclusion, indoor air pollutants increase the risk of AD aggravation in children and toluene in the indoor environment might act as an aggravating factor.

Atopic dermatitis (AD) is a chronic relapsing inflammatory skin disease and a growing health concern, especially in children, because of its high prevalence and associated low quality of life. Genetic predisposition, environmental triggers, or interactions between them contribute to the pathophysiology of AD. Therefore, it is very important to identify and control risk factors from the environment in susceptible subjects for successful treatment and prevention. Both indoor and outdoor air pollution, which are of increasing concern with urbanization, are well-known environmental risk factors for asthma, whereas there is relatively little evidence in AD. This review highlights epidemiologic and experimental data on the role of air pollution in patients with AD. Recent evidence suggests that a variety of air pollutants, such as environmental tobacco smoke, volatile organic compounds, formaldehyde, toluene, nitrogen dioxide, and particulate matter, act as risk factors for the development or aggravation of AD. These air pollutants probably induce oxidative stress in the skin, leading to skin barrier dysfunction or immune dysregulation. However, these results are still controversial because of the low number of studies, limitations in study design, inaccurate assessment of exposure and absorption, and many other issues. Further research about the adverse effects of air pollution on AD will help to expand our understanding and to establish a better strategy for the prevention and management of AD., (Copyright © 2014 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.)

Background: The occurrence of numerous cases of interstitial lung disease in children (chILD) every spring in Korea starting in 2006 raised suspicion about a causal relationship with the use of humidifier disinfectants (HDs). The aim of this study was to evaluate the association between HD use and the risk of chILD., Methods: This retrospective, 1∶3 matched case-control study consisted of 16 cases of chILD that had developed between 2010 and 2011. The three groups of parallel controls (patients with acute lobar pneumonia, asthma, and healthy children) were matched by age, gender, and index date. Indoor/outdoor environmental risk factors, including HD use, were investigated by asking the guardians to complete a questionnaire., Results: The median age of the affected children (43.8% male) was 26 months (18.25-36.25). The chILD group did not differ significantly from the control groups with respect to socio-demographic and clinical variables. Indoor and outdoor environmental factors were not associated with a risk of chILD. However, the previous use of HDs (OR; 2.73. 95% CI; 1.41-5.90, P = 0.00) were independently associated with an increased risk., Conclusions: This study showed that HDs, which are widely used in South Korea in the winter season, independently increased the risk of chILD in spring. Therefore, continuous monitoring and, if needed, changes in policy are essential to prevent and control pediatric diseases caused by toxic chemicals.

We performed this study to assess the prevalence of sensitization to aeroallergens and to analyze the difference between prevalence rates according to children's ages and residential areas. In this nationwide cross-sectional study, first grade students of 45 elementary schools and 40 middle schools were randomly selected, and skin prick tests were performed for 18 inhalant allergens between October and November 2010. Of 7,829 analyzed subjects, 3,753 (47.9%) were sensitized to at least one aeroallergen. Sensitization to Dermatophagoides farinae was found to be the most prevalent in elementary schoolchildren (32.4%), followed by Dermatophagoides pteronyssinus, Tyrophagus putrescentiae, Japanese hop, and oak. In middle schoolchildren, D. pteronyssinus yielded the highest prevalence (42.7%), followed by D. farinae, T. putrescentiae, Japanese hop, and cat. In middle schoolchildren, the sensitization rate to aeroallergens in metropolitan, urban, and rural areas was 57.2%, 54.3%, and 49.8%, respectively (P = 0.019). In this age group, the sensitization rate in low, middle, high, and very high income groups was 53.8%, 51.8%, 59.0%, and 59.6%, respectively (P = 0.002). In conclusion, the sensitization rate is 47.9% and house dust mite is the most prevalent allergen in the pediatric population in Korea. The rate is higher in metropolitan areas and the highest income group than in rural areas and low income groups.

In day-to-day living, individuals are exposed to various environmentally hazardous substances that have been associated with diverse diseases. Exposure to air pollutants can occur during breathing, posing a considerable risk to those with environmental health vulnerabilities. Among vulnerable individuals, maternal exposure can negatively impact the mother and child in utero. The developing fetus is particularly vulnerable to environmentally hazardous substances, with potentially greater implications. Among air pollutants, toluene is neurotoxic, and its effects have been widely explored. However, the impact of low-level toluene exposure in daily life remains unclear. Herein, we evaluated 194 mothers and infants from the Growing children's health and Evaluation of Environment (GREEN) cohort to determine the possible effects of early-life toluene exposure on the nervous system. Using Omics experiments, the effects of toluene were confirmed based on epigenetic changes and altered mRNA expression. Various epigenetic changes were identified, with upregulated expression potentially contributing to diseases such as glioblastoma and Alzheimer's, and downregulated expression being associated with structural neuronal abnormalities. These findings were detected in both maternal and infant groups, suggesting that maternal exposure to environmental hazardous substances can negatively impact the fetus. Our findings will facilitate the establishment of environmental health policies, including the management of environmentally hazardous substances for vulnerable groups. [ABSTRACT FROM AUTHOR]

Air pollution may influence prenatal maternal stress, but research evidence is scarce. Using data from a prospective cohort study conducted on pregnant women (n = 2153), we explored the association between air pollution and perceived stress, which was assessed using the 14-item Perceived Stress Scale (PSS), among pregnant women. Average exposures to particulate matter with an aerodynamic diameter of < 2.5 µm (PM2.5) or < 10 µm (PM10), nitrogen dioxide (NO2), and ozone (O3) for each trimester and the entire pregnancy were estimated at maternal residential addresses using land-use regression models. Linear regression models were applied to estimate associations between PSS scores and exposures to each air pollutant. After adjustment for potential confounders, interquartile-range (IQR) increases in whole pregnancy exposures to PM2.5, PM10, and O3 in the third trimester were associated with 0.37 (95% confidence interval [CI] 0.01, 0.74), 0.54 (95% CI 0.11, 0.97), and 0.30 (95% CI 0.07, 0.54) point increases in prenatal PSS scores, respectively. Furthermore, these associations were more evident in women with child-bearing age and a lower level of education. Also, the association between PSS scores and PM10 was stronger in the spring. Our findings support the relationship between air pollution and prenatal maternal stress. [ABSTRACT FROM AUTHOR]

Background: Atopic dermatitis (AD) is a chronic inflammatory skin disease that affects 20% of children worldwide. Environmental factors including weather and air pollutants have been shown to be associated with AD symptoms. However, the time‐dependent nature of such a relationship has not been adequately investigated. This paper aims to assess whether real‐time data on weather and air pollutants can make short‐term prediction of AD severity scores. Methods: Using longitudinal data from a published panel study of 177 paediatric patients followed up daily for 17 months, we developed a statistical machine learning model to predict daily AD severity scores for individual study participants. Exposures consisted of daily meteorological variables and concentrations of air pollutants, and outcomes were daily recordings of scores for six AD signs. We developed a mixed‐effect autoregressive ordinal logistic regression model, validated it in a forward‐chaining setting and evaluated the effects of the environmental factors on the predictive performance. Results: Our model successfully made daily prediction of the AD severity scores, and the predictive performance was not improved by the addition of measured environmental factors. Potential short‐term influence of environmental exposures on daily AD severity scores was outweighed by the underlying persistence of preceding scores. Conclusions: Our data does not offer enough evidence to support a claim that weather or air pollutants can make short‐term prediction of AD signs. Inferences about the magnitude of the effect of environmental factors on AD severity scores require consideration of their time‐dependent dynamic nature. [ABSTRACT FROM AUTHOR]

Background: Air pollution is regarded as a potential reason for the development or aggravation of allergic diseases. Objective: To investigate the relationship between exposure to outdoor air pollution during the first year of life and the development of allergic diseases, and to determine the association between outdoor air pollution near the residence and recent symptoms of allergic diseases in children. Methods: A nationwide cross-sectional survey was conducted in 6- to 7-year-old children. Among them, subjects who had been born (n = 1828) or lived (n = 1894) within 2 km of the nearest air quality monitoring sites were selected. The prevalence of allergic diseases was assessed by using questionnaires. Each subject was examined by pediatricians to determine the presence of eczema. Publicly available data were used regarding the daily ambient concentrations of sulfur dioxide, nitrogen dioxide, ozone, carbon monoxide (CO), and particulate matter. Results: For a 100 ppb increase in the mean daily CO level during the first year of life, the adjusted odds ratio for lifetime allergic rhinitis was 1.10 (95% confidence interval, 1.03-1.19). For a 1 ppm increase in the annual average CO level during the past 12 months, the adjusted odds ratio for the presence of atopic dermatitis on the day of the survey was 8.11 (95% confidence interval, 1.06-62.12). However, the other air pollutants showed no statistical significance. Conclusions: Higher exposure to CO during infancy increased the risk of development of allergic rhinitis. The risk of current atopic dermatitis symptoms increased in children who were exposed to higher CO levels during the past 12 months. [ABSTRACT FROM AUTHOR]

Precise exposure assessment of air pollutants is crucial in epidemiologic studies to ensure valid estimates of health effects. We conducted a longitudinal study to evaluate the role of air quality monitoring (AQM) measurements and high-resolution modeling outcomes focusing on nitrogen dioxide (NO2) exposure and atopic dermatitis (AD). A total of 128 young children with AD in Seoul Metropolitan Area, Korea, were recruited as a panel. We estimated the participants' exposure to NO2 for four months, from 1 April through 31 July 2014 based on (1) monitored levels from 60 AQM stations located at varying distances from residential areas (AQM station-based NO2, AQM-NO2) and (2) estimates from a community multi-scale air quality (CMAQ) modeling system with a high-resolution (1 × 1 km) (CMAQ-NO2). We then compared the effect of AQM-NO2 on AD symptoms with that of CMAQ-NO2. The average distance between the participants' residences and the nearest AQM station was 2.03 ± 1.06 km, ranging from 0.28 km to 5.73 km. Based on AQM-NO2, the AD symptoms increased by 10.28% (95% confidence interval (CI): 3.24, 17.79) with an increase of 10 ppb of NO2. The effect estimates of CMAQ-NO2 were similar to those of AQM-NO2 when assessed in patients living within 3 km from the nearest AQM station. Even within 1 km, the CI estimate obtained from the CMAQ was much narrower than from AQM (44.18–49.54 vs. 7.02–64.75). However, the association of AQM-NO2 with AD symptoms of patients living beyond 3 km was not positive, whereas that of CMAQ-NO2 maintained positive. In conclusion, exposure to ambient NO2 is significantly associated with aggravation of AD symptoms in young children. In addition, our study suggests that exposure assessment of NO2 using measurement data obtained from monitoring stations far from residential locations can lead to misclassification bias. [ABSTRACT FROM AUTHOR]

We estimated the exposure to ambient air pollutants and analyzed the associations with allergic diseases. We enrolled 177 children with atopic dermatitis (AD) and 70 asthmatic adults living in Seoul Metropolitan Area, Korea, and followed for 17 months between August 2013 and December 2014. Parents or patients recorded symptom scores on a daily basis. Exposure to particulate matter with a diameter < 10 μm (PM 10 ) and nitrogen dioxide (NO 2 ) was estimated in four different ways in each individual, using the AQ1 (measurements from the nearest air quality monitoring station to residential houses), AQ2 (measurements modified from AQ1 with the indoor level of air pollutants and time activity of each individual), AQ1-DI, and AQ2-DI (measurements modified from AQ1 and AQ2, respectively, with daily inhalation intakes of air pollutants). A generalized linear mixed model (GLMM) was used to analyze the associations between exposure metrics and clinical symptoms after adjusting for ambient temperature and humidity, age, season, gender, and time trend. The exposure metrics for PM 10 and NO 2 showed different distributions. Symptoms of AD and asthma were positively associated with exposure to PM 10 , but not NO 2 , in all exposure metrics. The effect size of PM 10 exposure on asthma symptoms was slightly greater in metrics with inhalation capacity (AQ-DIs) than in those without (AQs). This pattern was not observed in AD. Exposure to PM 10 is associated with symptom aggravation in childhood AD and adult asthma. Different exposure estimates may be used to evaluate the impact of air pollution on different allergic diseases. [ABSTRACT FROM AUTHOR]