Air pollution and pulmonary function in asthmatic children: effects of prenatal and lifetime exposures

Monthly average air pollution models using geographically weighted regression in Europe from 2000 to 2019

Detailed spatial models of monthly air pollution levels at a very fine spatial resolution (25 m) can help facilitate studies to explore critical time-windows of exposure at intermediate term. Seasonal changes in air pollution may affect both levels and spatial patterns of air pollution across Europe. We built Europe-wide land-use regression (LUR) models to estimate monthly concentrations of regulated air pollutants (NO2, O3, PM10 and PM2.5) between 2000 and 2019. Monthly average concentrations were collected from routine monitoring stations. Including both monthly-fixed and -varying spatial variables, we used supervised linear regression (SLR) to select predictors and geographically weighted regression (GWR) to estimate spatially-varying regression coefficients for each month. Model performance was assessed with 5-fold cross-validation (CV). We also compared the performance of the monthly LUR models with monthly adjusted concentrations. Results revealed significant monthly variations in both estimates and model structure, particularly for O3, PM10, and PM2.5. The 5-fold CV showed generally good performance of the monthly GWR models across months and years (5-fold CV R2: 0.31-0.66 for NO2, 0.4-0.79 for O3, 0.4-0.78 for PM10, 0.46-0.87 for PM2.5). Monthly GWR models slightly outperformed monthly-adjusted models. Correlations between monthly GWR model were generally moderate to high (Pearson correlation >0.6). In conclusion, we are the first to develop robust monthly LUR models for air pollution in Europe. These monthly LUR models, at a 25 m spatial resolution, enhance epidemiologists to better characterize Europe-wide intermediate-term health effects related to air pollution, facilitating investigations into critical exposure time windows in birth cohort studies.

Urban environment during pregnancy and lung function, wheezing, and asthma in school-age children. The generation R study

The urban environment during pregnancy may influence child's respiratory health, but scarce evidence exists on systematic evaluation of multiple urban exposures (e.g., air pollution, natural spaces, noise, built environment) on children's lung function, wheezing, and asthma development. We aimed to examine the association of the urban environment during pregnancy with lung function, preschool wheezing, and school-age asthma. We included 5624 mother-child pairs participating in a population-based prospective birth cohort. We estimated 30 urban environmental exposures including air pollution, road traffic noise, traffic, green spaces, blue spaces, and built environment during pregnancy. At 10 years of age, lung function was measured by spirometry. Information on preschool wheezing and physician-diagnosed school-age asthma was obtained from multiple questionnaires. We described single-exposure associations with respiratory outcomes using an exposome-wide association study. We also identified patterns of urban exposures with hierarchical clustering on principal components analysis and examined their associations with respiratory outcomes using multivariate regression models. Single-exposure analyses showed associations of higher particulate matter (PM) with lower mid-expiratory flow (FEF25-75%) (e.g., for PM < 2.5 μm of diameter [PM2.5] z-score = -0.06 [-0.09, -0.03]) and higher forced expiratory volume in 1s (FEV1) and forced vital capacity (FVC) (e.g., for PM2.5 FEV1 0.05 [0.02, 0.08]) after correction for multiple-hypothesis testing. Cluster analysis described three patterns of urban exposures during pregnancy and showed that the cluster characterised by higher levels of air pollution, noise, walkability, street connectivity, and lower levels of natural spaces were associated with lower FEF25-75% (-0.08 [-0.17, 0.00]), and higher odds of preschool wheezing (1.21 [1.03, 1.43]). This study shows that the characteristics of the urban environment during pregnancy are of relevance to the offspring's respiratory health during childhood.

Early life exposure to particulate matter and childhood asthma in Beijing, China: a case-control study

A case-control study was conducted to examine the association of particulate matter exposure during the pre-natal (the first, second, and third trimesters. and the whole pregnancy) and post-natal periods (the first year after birth) with childhood asthma in Beijing, China. Multivariable logistic regressions showed that childhood asthma was significantly associated with exposures to PM2.5 and PM10 during the entire pregnancy, with ORs of 1.28(95%CI:1.06-1.56) and 1.21(95%CI:1.02-1.42), respectively. The highest association with a 10 μg/m3 increase in PM2.5 and PM10 were both seen for the second trimester, with ORs of 1.17(95% CI: 1.05-1.30) and 1.14(95% CI: 1.04-1.24). Subgroup analyses suggested that significant and positive effects were subject to be observed in children with a family history of atopy. This study added evidence that exposures to PM2.5 and PM10 during pregnancy might increase the risk of childhood asthma in seriously polluted area, highlighting stronger associations in the second trimester.

Characterizing the neuroimmune environment of offspring in a novel model of maternal allergic asthma and particulate matter exposure

Inflammation during pregnancy is associated with an increased risk for neurodevelopmental disorders (NDD). Increased gestational inflammation can be a result of an immune condition/disease, exposure to infection, and/or environmental factors. Epidemiology studies suggest that cases of NDD are on the rise. Similarly, rates of asthma are increasing, and the presence of maternal asthma during pregnancy increases the likelihood of a child being later diagnosed with NDD such as autism spectrum disorders (ASD). Particulate matter (PM), via air pollution, is an environmental factor known to worsen the symptoms of asthma, but also, PM has been associated with increased risk of neuropsychiatric disorders. Despite the links between asthma and PM with neuropsychiatric disorders, there is a lack of laboratory models investigating combined prenatal exposure to asthma and PM on offspring neurodevelopment. Thus, we developed a novel mouse model that combines exposure to maternal allergic asthma (MAA) and ultrafine iron-soot (UIS), a common component of PM. In the current study, female BALB/c mice were sensitized for allergic asthma with ovalbumin (OVA) prior to pregnancy. Following mating and beginning on gestational day 2 (GD2), dams were exposed to either aerosolized OVA to induce allergic asthma or phosphate buffered saline (PBS) for 1 h. Following the 1-h exposure, pregnant females were then exposed to UIS with a size distribution of 55 to 169 nm at an average concentration of 176 ± 45 μg/m3) (SD), or clean air for 4 h, over 8 exposure sessions. Offspring brains were collected at postnatal days (P)15 and (P)35. Cortices and hippocampal regions were then isolated and assessed for changes in cytokines using a Luminex bead-based multiplex assay. Analyses identified changes in many cytokines across treatment groups at both timepoints in the cortex, including interleukin-1 beta (IL-1β), and IL-17, which remained elevated from P15 to P35 in all treatment conditions compared to controls. There was a suppressive effect of the combined MAA plus UIS on the anti-inflammatory cytokine IL-10. Potentially shifting the cytokine balance towards more neuroinflammation. In the hippocampus at P15, elevations in cytokines were also identified across the treatment groups, namely IL-7. The combination of MAA and UIS exposure (MAA-UIS) during pregnancy resulted in an increase in microglia density in the hippocampus of offspring, as identified by IBA-1 staining. Together, these data indicate that exposure to MAA, UIS, and MAA-UIS result in changes in the neuroimmune environment of offspring that persist into adulthood.

Characterizing the Neuroimmune Environment of Offspring in a Novel Model of Maternal Allergic Asthma and Particulate Matter Exposure

Autism spectrum disorders (ASD) are neurodevelopmental disorders characterized by the presence of decreased social interactions and an increase in stereotyped and repetitive behaviors. Epidemiology studies suggest that cases of ASD are on the rise. Similarly, rates of asthma are increasing, and the presence of maternal asthma during pregnancy increases the likelihood of a child being later diagnosed with ASD. Particulate matter (PM), via air pollution, is an environmental factor known to worsen the symptoms of asthma, but also, PM has been associated with increased risk of neuropsychiatric disorders including ASD. Despite the links between asthma and PM with neuropsychiatric disorders, there is a lack of laboratory models investigating combined prenatal exposure to asthma and PM on offspring neurodevelopment. Thus, we developed a novel mouse model that combines exposure to maternal allergic asthma (MAA) and ultrafine iron-soot (UIS), a common component of PM. In the current study, female BALB/c mice were primed for allergic asthma with ovalbumin (OVA) prior to pregnancy. Following mating and beginning on gestational day 2 (GD2), dams were exposed to either aerosolized OVA or phosphate buffered saline (PBS) for 1 hour. Following the 1-hour exposure, pregnant females were then exposed to UIS or clean air for 4 hours. Offspring brains were collected at postnatal days (P)15 and (P)35. Cortices and hippocampal regions were then isolated and assessed for changes in cytokines using a Luminex bead-based multiplex assay. Analyses identified changes in many cytokines across treatment groups at both timepoints in the cortex, including interleukin-1 beta (IL-1β), IL-2, IL-13, and IL-17, which remained elevated from P15 to P35 in all treatment conditions compared to controls. In the hippocampus at P15, elevations in cytokines were also identified across the treatment groups, namely interferon gamma (IFNγ) and IL-7. The combination of MAA and UIS exposure (MAA-UIS) during pregnancy resulted in an increase in microglia density in the hippocampus of offspring, as identified by IBA-1 staining. Together, these data indicate that exposure to MAA, UIS, and MAA-UIS result in changes in the neuroimmune environment of offspring that persist into adulthood.

The final 28 Days:Prenatal exposure to air pollution and child anthropometric outcomes

This study examines the health consequences of prenatal exposure to air pollution by combining child health data from an original survey with the Air Pollution Index (API) from official Chinese statistics. Our results show that exposure to air pollution in late trimester (four-week windows before delivery) is negatively associated with health outcomes in children in the short and long terms. One standard deviation increase in the API in the final 28 days before delivery decreased birth weight and length by 0.388 and 0.458, respectively, in z-scores and lowered the weight-for-age and height-for-age by 0.370 and 0.441, respectively, in z-scores at 13-15 years post-exposure. Although the timing of exposure and its consequences have been the subject of debate in existing literature, our results focus on four-week windows and demonstrate that exposure during the late pregnancy period may have adverse health effects on children. We conducted analyses that accounted for potential covariates and omitted variables, and our results remain robust and statistically significant. We also found gender heterogeneous effects that girls are more vulnerable to fetal air pollution exposure than boys. Our findings uncover fetal and child health risks regarding air pollution and reinforce the importance of policies for mitigating air pollution in developing countries.

Air quality and respiratory health in children

Air pollution is a leading modifiable risk factor for various cardio-respiratory outcomes globally, both for children and for adults. Children are particularly susceptible to the adverse effects of air pollution due to various physiological and behavioural factors. Children are at a higher risk of outcomes such as acute respiratory infections, asthma and decreased lung function due to air pollution exposure; the risk varies in different geographical regions, depending on the source of air pollution, duration of exposures and concentration. Prenatal exposure to air pollution may also contribute to adverse respiratory outcomes later in life.

A life course approach to asthma and wheezing among young children caused by ozone: A prospective birth cohort in northern China

BACKGROUND

Given differences in vulnerability of children in early life, a life course approach to asthma and wheezing (AW) in young children caused by ozone (O₃) is not fully understood.

METHODS

We conducted a birth cohort in Jinan, China from 2018 to 2021 to elucidate the onset model of childhood AW due to O₃ exposure. An inverse distance weighted model was used for individual exposure assessment. The time-dependent Cox proportional-hazard model and logistic model were used to investigate the effects of O₃ exposure on AW. Principal component analysis, interaction analysis, and distributed lag model were used to analyze the life course approach.

RESULTS

The cumulative incidence rate for AW among 6501 children aged 2 was 1.4%. A high level of O₃ was related to AW (HR: 2.10, 95% CI: 1.31, 3.37). Only O₃ exposure after birth was associated with AW, with an OR of 1.82 (1.08, 3.12), after adjusting for the effect before birth. Furthermore, adjusting for other air pollutants, the HR for the individual effect of high O₃ exposure on AW was 2.44 (1.53, 3.89). Interestingly, P values for interactions for O₃ and the principal components of other pollutants, as well as the characteristic variable of open windows were less than 0.1. Moreover, an increase in the IQR of O₃ exposure at the 31st to 37th weeks before birth and the 1st to 105th weeks after birth was associated with an increase in the HRs for AW.

CONCLUSIONS

High-level of O₃ exposure after birth could lead to AW among young children. Importantly, the AW onset model may include the risk factors accumulation and the sensitive period model. Specifically, there are two sensitive windows in early life, and the correlated insults between the high level of O₃ and other pollutants as well as open windows in the asthma-inducing effect.

Pre-natal exposure to NO2 and PM2.5 and newborn lung function: An approach based on repeated personal exposure measurements

CONTEXT

While strong evidence supports adverse effects of pre-natal air pollution on child's lung function, previous studies rarely considered fine particulate matter (PM_2.5) or the potential role of offspring sex and no study examined the effects of pre-natal PM_2.5 on the lung function of the newborn.

AIM

We examined overall and sex-specific associations of personal pre-natal exposure to PM_2.5 and nitrogen (NO₂) with newborn lung function measurements.

METHODS

This study relied on 391 mother-child pairs from the French SEPAGES cohort. PM_2.5 and NO₂ exposure was estimated by the average concentration of pollutants measured by sensors carried by the pregnant women during repeated periods of one week. Lung function was assessed with tidal breathing analysis (TBFVL) and nitrogen multiple breath washout (N₂MBW) test, performed at 7 weeks. Associations between pre-natal exposure to air pollutants and lung function indicators were estimated by linear regression models adjusted for potential confounders, and then stratified by sex.

RESULTS

Mean exposure to NO₂ and PM_2.5 during pregnancy was 20.2 μg/m³ and 14.3 μg/m³, respectively. A 10 μg/m³ increase in PM_2.5 maternal personal exposure during pregnancy was associated with an adjusted 2.5 ml (2.3%) decrease in the functional residual capacity of the newborn (p-value = 0.11). In females, functional residual capacity was decreased by 5.2 ml (5.0%) (p = 0.02) and tidal volume by 1.6 ml (p = 0.08) for each 10 μg/m³ increase in PM_2.5. No association was found between maternal NO₂ exposure and newborns lung function.

CONCLUSIONS

Personal pre-natal PM_2.5 exposure was associated with lower lung volumes in female newborns, but not in males. Our results provide evidence that pulmonary effects of air pollution exposure can be initiated in utero. These findings have long term implications for respiratory health and may provide insights into the underlying mechanisms of PM_2.5 effects.

Outdoor air pollution exposure and the risk of asthma and wheezing in the offspring

According to the "fetal origin of disease" hypothesis, air pollution exposure in pregnancy may play an important role in stimulating the early programming of asthma and allergies. However, previous studies reported inconsistent findings. The aim of this meta-analysis was to provide higher grade evidence and quantitatively analyze the link between prenatal exposure to outdoor air pollutants and childhood asthma and wheezing. Databases (Web of Science and PubMed) were extensively searched for articles published from the start of the database to September 15, 2021. Either random-effect model or fixed-effect model was used to estimate the disease-specific relative risks (RR) with the corresponding 95% confidence intervals (CIs) to estimate the association. Newcastle-Ottawa Quality Score (NOS) was used to assess the quality of studies. This study finally included 13 cohort studies, and the findings showed that NO₂ and SO₂ exposure during entire pregnancy was significantly associated with wheezing (RR = 1.032, 95% CI: 1.000, 1.066) and asthma (RR = 1.114, 95% CI: 1.066, 1.164), respectively. Further analyses showed that PM_2.5 were positively associated with asthma in the second (RR = 1.194, 95% CI: 1.143, 1.247) and third trimester (RR = 1.050, 95% CI: 1.007, 1.094), while NO₂ (RR = 1.060, 95% CI: 1.021, 1.101) and SO₂ (RR = 1.067, 95% CI: 1.013, 1.123) were shown positively associated with asthma only in the second trimester. The relationship between wheezing and outdoor air pollutants was not significant in any of the pregnancy subgroups. This study suggests that prenatal exposure of outdoor air pollution may increase the asthma and wheezing risk in the offspring and that the second trimester may be a sensitive period for air pollution exposure. But the interpretation of the causal association is hampered by limited number of studies on dose response.

NO2 and PM2.5 air pollution co-exposure and temperature effect modification on pre-mature mortality in advanced age: a longitudinal cohort study in China

BACKGROUND

There is a discourse on whether air pollution mixture or air pollutant components are causally linked to increased mortality. In particular, there is uncertainty on whether the association of NO₂ with mortality is independent of fine particulate matter (PM_2.5). Furthermore, effect modification by temperature on air pollution-related mortality also needs more evidence.

METHODS

We used the Chinese Longitudinal Healthy Longevity Study (CLHLS), a prospective cohort with geographical and socio-economic diversity in China. The participants were enrolled in 2008 or 2009 and followed up in 2011-2012, 2014, and 2017-2018. We used remote sensing and ground monitors to measure nitrogen dioxide (NO₂), fine particulate matter (PM_2.5) , and temperature. We used the Cox-proportional hazards model to examine the association between component and composite air pollution and all-cause mortality, adjusted for demographic characteristics, lifestyle, geographical attributes, and temperature. We used the restricted cubic spline to visualize the concentration-response curve.

RESULTS

Our study included 11 835 individuals with an average age of 86.9 (SD: 11.4) at baseline. Over 55 606 person-years of follow-up, we observed 8 216 mortality events. The average NO₂ exposure was 19.1 μg/m³ (SD: 14.1); the average PM_2.5 exposure was 52.8 μg/m³ (SD: 15.9). In the single pollutant models, the mortality HRs (95% CI) for 10 μg/m³ increase in annual average NO₂ or PM_2.5 was 1.114 (1.085, 1.143) and 1.244 (1.221, 1.268), respectively. In the multi-pollutant model co-adjusting for NO₂ and PM_2.5, the HR for NO₂ turned insignificant: 0.978 (0.950, 1.008), but HR for PM_2.5 was not altered: 1.252 (1.227, 1.279). PM_2.5 and higher mortality association was robust, regardless of NO₂. When acccounting for particulate matter, NO₂ exposure appeared to be harmful in places of colder climates and higher seasonal temperature variation.

CONCLUSIONS

We see a robust relationship of PM_2.5 exposure and premature mortality in advance aged individuals, however, NO₂ exposure and mortality was only harmful in places of colder climate such as northeast China, indicating evidence of effect modification by temperature. Analysis of NO₂ without accounting for its collinearity with PM_2.5, may lead to overestimation.

Health Outcomes in Children Associated with Prenatal and Early-Life Exposures to Air Pollution: A Narrative Review

(1) Background: The developmental origins of health and disease (DOHaD) hypothesis links adverse fetal exposures with developmental mal-adaptations and morbidity later in life. Short- and long-term exposures to air pollutants are known contributors to health outcomes; however, the potential for developmental health effects of air pollution exposures during gestation or early-childhood have yet to be reviewed and synthesized from a DOHaD lens. The objective of this study is to summarize the literature on cardiovascular and metabolic, respiratory, allergic, and neuropsychological health outcomes, from prenatal development through early childhood, associated with early-life exposures to outdoor air pollutants, including traffic-related and wildfire-generated air pollutants. (2) Methods: We conducted a search using PubMed and the references of articles previously known to the authors. We selected papers that investigated health outcomes during fetal or childhood development in association with early-life ambient or source-specific air pollution exposure. (3) Results: The current literature reports that prenatal and early-childhood exposures to ambient and traffic-related air pollutants are associated with a range of adverse outcomes in early life, including cardiovascular and metabolic, respiratory and allergic, and neurodevelopmental outcomes. Very few studies have investigated associations between wildfire-related air pollution exposure and health outcomes during prenatal, postnatal, or childhood development. (4) Conclusion: Evidence from January 2000 to January 2022 supports a role for prenatal and early-childhood air pollution exposures adversely affecting health outcomes during development. Future studies are needed to identify both detrimental air pollutants from the exposure mixture and critical exposure time periods, investigate emerging exposure sources such as wildfire, and develop feasible interventional tools.

Cleaning Products Commonly Used in Oklahoma Family Child Care Homes: Implications for Respiratory Risk and Children's Health

Little is known about the cleaning products used by early care and education programs that contribute to childhood asthma, particularly in Oklahoma where rates of uncontrolled asthma are higher than national rates (60.0% vs. 50.3%, respectively). We conducted a cross-sectional study of cleaning products used by Oklahoma-licensed family child care homes (FCCHs) (n = 50) to characterize and identify potential respiratory-health risks associated with chemical contents. Overall, 386 chemicals were abstracted from the 132 reported products. Of these, 100 unique chemicals were identified. Four percent (4.2%) of providers used a product with a sensitizer that may cause allergy or asthma symptoms if inhaled and 35.4% used a product with an irritant that may cause irritation to the respiratory tract. Most (62.5%) reported using a product with a chemical that had a C=C double bond in its molecular structure that may make it highly reactive with other substances in the air and produce secondary air pollutants and 83.3% reported using a sodium hypochlorite containing product. Twenty-three percent reported products that contain carcinogens. Policy, educational, and technical assistance interventions are needed to promote the use of safer products and reduce respiratory and other health risks posed by chemicals in Oklahoma FCCHs.

Associations between pre- and postnatal exposure to air pollution and lung health in children and assessment of CC16 as a potential mediator

BACKGROUND

Early life exposure to air pollution can affect lung health. Previous studies have not assessed the implications of both pre- and postnatal exposure to air pollutants on lung function at repeated ages during childhood. In addition, there is the need to identify potential mediators of such effect.

OBJECTIVES

To longitudinally assess the association between pre- and postnatal air pollution exposure and lung function during childhood. We also aimed to explore the role of Club cell secretory protein (CC16) as a potential mediator in this association.

METHODOLOGY

We included 487 mother-child pairs from the INMA (INfancia y Medio Ambiente) Sabadell birth cohort, recruited between 2004 and 2006. Air pollution exposure was estimated for pregnancy, pre-school age, and school-age using temporally adjusted land use regression (LUR) modelling. Lung function was measured at ages 4, 7, 9 and 11 by spirometry. At age 4, serum CC16 levels were determined in 287 children. Multivariable linear regression models and linear mixed modelling were applied, while considering potential confounders.

RESULTS

Prenatal exposure to Particulate Matter (PM)₁₀ and PM_coarse had the most consistent associations with reduced lung function in cross-sectional models. Associations with postnatal exposure were less consistent. Increasing CC16 levels at 4 years were associated with an increase in FEF_25-75 (β = 120.4 mL, 95% CI: 6.30, 234.5) from 4 to 11 years of age. No statistically significant associations were found between pre- or postnatal air pollution and CC16 at age 4.

CONCLUSION

Increasing levels of air pollution exposure, particularly prenatal PM₁₀ and PM_coarse exposure, were associated with a reduction in lung function. We were not able to confirm our hypothesis on the mediation role of CC16 in this association, however our results encourage further exploration of this possibility in future studies.

Trends of Ground-Level Ozone in New York City Area during 2007–2017

The spatiotemporal patterns of ground level ozone (O3) concentrations in the New York City (NYC) metropolitan region for the 2007–2017 period were examined conjointly with local emissions of O3 precursors and the frequency of wildfires. Daily 8-h and 1-h O3 and nitric oxide (NO) concentrations were retrieved from the US Environmental Protection Agency (EPA) Air Data. Annual emission inventories for 2008 and 2017 were acquired from EPA National Emissions Inventory (NEI). The number and area burnt by natural and human-ignited wildfires were acquired from the National Interagency Fire Center (NIFC). The highest daily 8-h max O3 concentrations varied from 90 to 111 parts per billion volume (ppbv) with the highest concentrations measured perimetrically to NYC urban agglomeration. The monthly 8-h max O3 levels have been declining for most of the peri-urban sites but increasing (from +0.18 to +1.39 ppbv/year) for sites within the urban agglomeration. Slightly higher O3 concentrations were measured during weekend than those measured during the weekdays in urban sites probably due to reduced O3 titration by NO. Significant reductions of locally emitted anthropogenic nitrogen oxides (NOx) and volatile organic compounds (VOCs) may have triggered the transition from VOC-limited to NOX-limited conditions, with downwind VOCs sources being critically important. Strong correlations between the monthly 8-h max O3 concentrations and wildfires in Eastern US were computed. More and destructive wildfires in the region were ignited by lightning for years with moderate and strong La Niña conditions. These findings indicate that climate change may counterbalance current and future gains on O3 precursor’s reductions by amending the VOCs-to-NOx balance.

Environmental Health-Related Policies and Practices of Oklahoma Licensed Early Care and Education Programs: Implications for Childhood Asthma

Little is known about the environmental health-related policies and practices of early care and education (ECE) programs that contribute to childhood asthma, particularly in Oklahoma where child asthma rates (9.8%) and rates of uncontrolled asthma among children with asthma (60.0%) surpass national rates (8.1% and 50.3%, respectively). We conducted a cross-sectional survey with directors of Oklahoma-licensed ECE programs to assess policies and practices related to asthma control and to evaluate potential differences between Centers and Family Childcare Homes (FCCHs). Surveyed ECEs (n = 476) included Centers (56.7%), FCCHs (40.6%), and other program types (2.7%). Almost half (47.2%) of directors reported never receiving any asthma training. More Center directors were asthma-trained than FCCH directors (61.0% versus 42.0%, p < 0.0001). Most ECEs used asthma triggers, including bleach (88.5%) and air fresheners (73.6%). Centers were more likely to use bleach daily than were FCCHs (75.6% versus 66.8%, p = 0.04). FCCHs used air fresheners more than did Centers (79.0% versus 61.0%, p < 0.0001). The majority of ECEs (74.8%) used pesticides indoors. Centers applied indoor pesticides more frequently (i.e., monthly or more often) than did FCCHs (86.0% versus 58.0%, p < 0.0001). Policy, educational, and technical assistance interventions are needed to reduce asthma triggers and improve asthma control in Oklahoma ECEs.

Prenatal exposure to air pollutants and childhood atopic dermatitis and allergic rhinitis adopting machine learning approaches: 14-year follow-up birth cohort study

The incidence of childhood atopic dermatitis (AD) and allergic rhinitis (AR) is increasing. This warrants development of measures to predict and prevent these conditions. We aimed to investigate the predictive ability of a spectrum of data mining methods to predict childhood AD and AR using longitudinal birth cohort data. We conducted a 14-year follow-up of infants born to pregnant women who had undergone maternal examinations at nine selected maternity hospitals across Taiwan during 2000-2005. The subjects were interviewed using structured questionnaires to record data on basic demographics, socioeconomic status, lifestyle, medical history, and 24-h dietary recall. Hourly concentrations of air pollutants within 1 year before childbirth were obtained from 76 national air quality monitoring stations in Taiwan. We utilized weighted K-nearest neighbour method (k = 3) to infer the personalized air pollution exposure. Machine learning methods were performed on the heterogeneous attributes set to predict allergic diseases in children. A total of 1439 mother-infant pairs were recruited in machine learning analysis. The prevalence of AD and AR in children up to 14 years of age were 6.8% and 15.9%, respectively. Overall, tree-based models achieved higher sensitivity and specificity than other methods, with areas under receiver operating characteristic curve of 83% for AD and 84% for AR, respectively. Our findings confirmed that prenatal air quality is an important factor affecting the predictive ability. Moreover, different air quality indices were better predicted, in combination than separately. Combining heterogeneous attributes including environmental exposures, demographic information, and allergens is the key to a better prediction of children allergies in the general population. Prenatal exposure to nitrogen dioxide (NO₂) and its concatenation changes with time were significant predictors for AD and AR till adolescent.

Establishing a sorting protocol for healthcare databases

Background: Health information records in many countries, especially developing countries, are still paper based. Compared to electronic systems, paper-based systems are disadvantageous in terms of data storage and data extraction. Given the importance of health records for epidemiological studies, guidelines for effective data cleaning and sorting are essential. They are, however, largely absent from the literature. The following paper discusses the process by which an algorithm was developed for the cleaning and sorting of a database generated from emergency department records in Lebanon.

Design and methods: Demographic and health related information were extracted from the emergency department records of three hospitals in Beirut. Appropriate categories were selected for data categorization. For health information, disease categories and codes were selected according to the International Classification of Disease 10^th Edition.

Results: A total of 16,537 entries were collected. Demographic information was categorized into groups for future epidemiological studies. Analysis of the health information led to the creation of a sorting algorithm which was then used to categorize and code the health data. Several counts were then performed to represent and visualize the data numerically and graphically.

Conclusions: The article describes the current state of health information records in Lebanon and the associated disadvantages of a paper-based system in terms of storage and data extraction. Furthermore, the article describes the algorithm by which health information was sorted and categorized to allow for future data analysis using paper records.

Exploring Asymmetric Nexus Between CO2 Emissions, Environmental Pollution, and Household Health Expenditure in China

Objective

This study investigates the nexus between household health expenditure, CO₂ emissions and environmental pollution in China. We analyzed the asymmetric dynamic relationship between CO₂ emissions, environmental pollution and household health expenditure for the period 1990 to 2019 in China.

Methods

This study adopted nonlinear autoregressive distributed lag (NARDL) and Granger causality following the diagnostic test. Furthermore, we applied Dickey-Fuller (ADF), PP unit root tests, Zivot and Andrews test for structural breaks in our analysis. The NARDL is the most suitable econometric technique for estimations, especially if the asymmetric relationship exists among the variables. NARDL technique is capable to explore the dynamic relationship between CO₂ emissions, environmental pollution and household health expenditure.

Results

The empirical results verify the asymmetric nexus between CO₂ emissions, environmental pollution and household health expenditure in the context of China. The outcomes revealed that in the short run and long run positive shocks of CO₂ emissions and environmental pollution positively affecting health expenditure, while negative shocks reduce health spendings. The results also demonstrate bi-directional causality among household health spendings, CO₂ emissions and environmental pollution.

Conclusion

Our results support many previous studies, documenting that CO₂ emissions positively contribute to the amount of household health expenditure, confirming the asymmetric relationship between CO₂ emissions and household health expenditure. The results also confirm the statistically significant and asymmetrically positive relationship between environmental pollution and household health expenditure. This implies that Chinese residents have to bear more household health expenditure, in the case of more CO₂ emissions and a greater amount of environmental pollution.

Impact of exposure to ambient air pollutants on the admission rate of hospitals for asthma disease in Shiraz, southern Iran

Asthma is a common chronic respiratory disease in the world. Short-term exposure to ambient air pollutants is closely related to acute respiratory diseases and asthmatic symptoms. The purpose of this research was to estimate the correlation between exposure to three air pollutants (O₃, NO₂, and SO₂) and hospital admission because of asthmatic disease (HAAD) in the city of Shiraz, southern Iran. The data were collected from the two real-time monitoring stations located in this city. The acquired information was used for developing predictive models by the AirQ software. The findings of this study were reported for two age groups (<15 and 15-64 years old). The highest levels of O₃, NO₂, and SO₂ were obtained 187.33 μg/m³, 34.1 μg/m³, and 491.2 μg/m³ in 2016, respectively, and 227.75 μg/m³, 92.26 μg/m³, and 190.21 μg/m³, respectively, in 2017. Among the mentioned pollutants, the yearly average concentration of SO₂ was 8.62 times more than the WHO guideline, during the studied times. The number of extra cases of HAAD for <15 years and 15-64 years caused by the air pollutants in Shiraz were estimated to be 273 and 36, respectively, in 2016, and 243 and 30 for 2017, respectively. The results of this work displayed that air pollutants have caused respiratory problems in Shiraz city. The AirQ model is a facile and potential tool for the prediction of asthma disease to reduce the health risk of atmospheric pollutants in the worldwide.

INTEGRATIVE STATISTICAL METHODS FOR EXPOSURE MIXTURES AND HEALTH

Humans are concurrently exposed to chemically, structurally and toxicologically diverse chemicals. A critical challenge for environmental epidemiology is to quantify the risk of adverse health outcomes resulting from exposures to such chemical mixtures and to identify which mixture constituents may be driving etiologic associations. A variety of statistical methods have been proposed to address these critical research questions. However, they generally rely solely on measured exposure and health data available within a specific study. Advancements in understanding of the role of mixtures on human health impacts may be better achieved through the utilization of external data and knowledge from multiple disciplines with innovative statistical tools. In this paper we develop new methods for health analyses that incorporate auxiliary information about the chemicals in a mixture, such as physicochemical, structural and/or toxicological data. We expect that the constituents identified using auxiliary information will be more biologically meaningful than those identified by methods that solely utilize observed correlations between measured exposure. We develop flexible Bayesian models by specifying prior distributions for the exposures and their effects that include auxiliary information and examine this idea over a spectrum of analyses from regression to factor analysis. The methods are applied to study the effects of volatile organic compounds on emergency room visits in Atlanta. We find that including cheminformatic information about the exposure variables improves prediction and provides a more interpretable model for emergency room visits for respiratory diseases.

IDENTIFYING MAIN EFFECTS AND INTERACTIONS AMONG EXPOSURES USING GAUSSIAN PROCESSES

This article is motivated by the problem of studying the joint effect of different chemical exposures on human health outcomes. This is essentially a nonparametric regression problem, with interest being focused not on a black box for prediction but instead on selection of main effects and interactions. For interpretability we decompose the expected health outcome into a linear main effect, pairwise interactions and a nonlinear deviation. Our interest is in model selection for these different components, accounting for uncertainty and addressing nonidentifiability between the linear and nonparametric components of the semiparametric model. We propose a Bayesian approach to inference, placing variable selection priors on the different components, and developing a Markov chain Monte Carlo (MCMC) algorithm. A key component of our approach is the incorporation of a heredity constraint to only include interactions in the presence of main effects, effectively reducing dimensionality of the model search. We adapt a projection approach developed in the spatial statistics literature to enforce identifiability in modeling the nonparametric component using a Gaussian process. We also employ a dimension reduction strategy to sample the nonlinear random effects that aids the mixing of the MCMC algorithm. The proposed MixSelect framework is evaluated using a simulation study, and is illustrated using data from the National Health and Nutrition Examination Survey (NHANES). Code is available on GitHub.

Low lung function in the developing world is analogous to stunting: a review of the evidence

Background: Low vital capacity, one of the consequences of restricted lung growth, is a strong predictor of cardiovascular mortality. Vital capacity is lower in the developing world than the developed world, even after adjusting for height, weight and gender. This difference is typically dismissed as ethnic variation, adjusted for by redefining normal. Whether this is a consequence of stunted lung growth, rather than just genetically smaller lungs, has not been investigated in detail. Therefore, we sought to compare factors implicated in both stunting and lung development, particularly in the developing world.

Methods: We conducted a manual screen of articles identified through Google Scholar and assessed risk of bias. No language restrictions were applied, so long as there was an associated English abstract. We queried VizHub (Global Burden of Disease Visualization Tool) and Google Dataset search engines for disease burden and genome wide association studies.  The scope of the article and the heterogeneity of the outcome measures reported required a narrative review of available evidence. To the extent possible, the review follows PRISMA reporting guidelines.

Results: Early life influences operate in synergism with genetic, environmental and nutritional factors to influence lung growth and development in children.  Low lung function and stunting have common anthropometric, environmental and nutritional correlates originating during early development. Similar anthropometric correlates shared chronic inflammatory pathways, indicated that the two conditions were analogous.

Conclusion: The analogy between poor lung function and stunting is conspicuous in the developing world, with malnutrition at the center of non -achievement of growth potential, susceptibility to infectious diseases and intrauterine programming for metabolic syndrome. This counter the idea of redefining the normal for lung function measurements, since observed inter-ethnic variations are likely a mix of natural genetic differences as well as differences in nurture such that reduced lung function reflects early life adversities.

The joint effect of ambient air pollution and agricultural pesticide exposures on lung function among children with asthma

BACKGROUND

Ambient environmental pollutants have been shown to adversely affect respiratory health in susceptible populations. However, the role of simultaneous exposure to multiple diverse environmental pollutants is poorly understood.

OBJECTIVE

We applied a multidomain, multipollutant approach to assess the association between pediatric lung function measures and selected ambient air pollutants and pesticides.

METHODS

Using data from the US EPA and California Pesticide Use Registry, we reconstructed three months prior exposure to ambient air pollutants ((ozone (O₃), nitrogen dioxide (NO₂), particulate matter with a median aerodynamic diameter < 2.5 μm (PM_2.5) and <10 μm (PM₁₀)) and pesticides (organophosphates (OP), carbamates (C) and methyl bromide (MeBr)) for 153 children with mild intermittent or mild persistent asthma from the San Joaquin Valley of California, USA. We implemented Bayesian kernel machine regression (BKMR) to estimate the association between simultaneous exposures to air pollutants and pesticides and lung function measures (forced expiratory volume in 1 s (FEV₁), forced vital capacity (FVC), and forced expiratory flow between 25% and 75% of vital capacity (FEF_25-75)).

RESULTS

In BKMR analysis, the overall effect of mixtures (pollutants and pesticides) was associated with reduced FEV₁ and FVC, particularly when all the environmental exposures were above their 60th percentile. For example, the effect of the overall mixture at the 70th percentile (compared to the median) was a -0.12SD (-50 mL, 95% CI: -180 mL, 90 mL) change in the FEV₁ and a -0.18SD (-90 mL, 95% CI: -240 mL, 60 mL) change in the FVC. However, 95% credible intervals around all of the joint effect estimates contained the null value.

CONCLUSION

At this agricultural-urban interface, we observed results from multipollutant analyses, suggestive of adverse effects on some pediatric lung function measures following a cumulative increase in ambient air pollutants and agricultural pesticides. Given the uncertainty in effect estimates, this approach should be explored in larger studies.

Associations between childhood and adolescence exposure to air pollution and adult height in polish women

Exposure to airborne substances harmful to health during pre- and postnatal stage may significantly affect the correct development of organs and systems. Many studies analyze the relationship between air quality and health, but data on the impact of air pollution on human biological development are scanty. The aim of the study was to assess the relationships between adult body height and air quality in the place of residence during childhood and adolescence. The parameters measured included absolute stature (cm) and relative stature defined as a percentage of mean stature of both parents. The analysis covered data collected from 1257 women. Subject's height was measured. Data on parental height were obtained using a questionnaire. The level of each analysed environmental pollution in the place of residence during childhood and adolescence: particulate matter (PM₁₀, PM_2.5)_, sulphur dioxide (SO₂)_, nitric dioxide (NO₂) and benzene (C₆H₆) in the place of residence during childhood and adolescence was determined on the basis of the data made available by the Polish Chief Inspectorate for Environmental Protection. Results of our study show that mean stature decreases with growing air pollution level. Significant differences were observed both in absolute stature and relative stature (expressed as percentage of mean stature of both parents) depending on PM₁₀ and PM_2.5 levels in place of residence during childhood and adolescence as well as on the total index of air quality. The differences remain statistically significant also after adjustment for the degree of urbanisation of the place of residence and factors related to socio-economic status. Our findings suggest that air pollution level in the place of residence during childhood and adolescence has significant impact on the children growth, potentially leading to worse health status later in life.

Prenatal, Early-Life, and Childhood Exposure to Air Pollution and Lung Function: The ALSPAC Cohort

Rationale: Exposure to air pollution during intrauterine development and through childhood may have lasting effects on respiratory health.Objectives: To investigate lung function at ages 8 and 15 years in relation to air pollution exposures during pregnancy, infancy, and childhood in a UK population-based birth cohort.Methods: Individual exposures to source-specific particulate matter ≤10 μm in aerodynamic diameter (PM₁₀) during each trimester, 0-6 months, 7-12 months (1990-1993), and up to age 15 years (1991-2008) were examined in relation to FEV₁% predicted and FVC% predicted at ages 8 (n = 5,276) and 15 (n = 3,446) years using linear regression models adjusted for potential confounders. A profile regression model was used to identify sensitive time periods.Measurements and Main Results: We did not find clear evidence of a sensitive exposure period for PM₁₀ from road traffic. At age 8 years, 1 μg/m³ higher exposure during the first trimester was associated with lower FEV₁% predicted (-0.826; 95% confidence interval [CI], -1.357 to -0.296) and FVC% predicted (-0.817; 95% CI, -1.357 to -0.276), but similar associations were seen for exposures for other trimesters, 0-6 months, 7-12 months, and 0-7 years. Associations were stronger among boys, as well as children whose mother had a lower education level or smoked during pregnancy. For PM₁₀ from all sources, the third trimester was associated with lower FVC% predicted (-1.312; 95% CI, -2.100 to -0.525). At age 15 years, no adverse associations with lung function were seen.Conclusions: Exposure to road-traffic PM₁₀ during pregnancy may result in small but significant reductions in lung function at age 8 years.

Asthma: New Integrative Treatment Strategies for the Next Decades

Asthma is a chronic disease whose main anatomical-functional alterations are grouped into obstruction, nonspecific bronchial hyperreactivity, inflammation and airway remodeling. Currently, the Global Initiative of Asthma 2020 (GINA 2020) suggests classifying it into intermittent cases, slightly persistent, moderately persistent and severely persistent, thus determining the correct guidelines for its therapy. In general, the drugs used for its management are divided into two groups, those with a potential bronchodilator and the controlling agents of inflammation. However, asthmatic treatments continue to evolve, and notable advances have been made possible in biological therapy with monoclonal antibodies and in the relationship between this disease and oxidative stress. This opens a new path to dietary and herbal strategies and the use of antioxidants as a possible therapy that supports conventional pharmacological treatments and reduces their doses and/or adverse effects. This review compiles information from different published research on risk factors, pathophysiology, classification, diagnosis and the main treatments; likewise, it synthesizes the current evidence of herbal medicine for its control. Studies on integrative medicine (IM) therapies for asthmatic control are critically reviewed. An integrative approach to the prevention and management of asthma warrants consideration in clinical practice. The intention is to encourage health professionals and scientists to expand the horizons of basic and clinical research (preclinical, clinical and integrative medicine) on asthma control.

Prenatal exposure to VOCs and NOx and lung function in preschoolers

BACKGROUND

Several studies have shown that exposure to air pollutants affects lung growth and development and can result in poor respiratory health in early life.

METHODS

We included a subsample of 772 Mexican preschoolers whose mothers participated in a Prenatal Omega-3 fatty acid Supplements, GRowth, And Development birth cohort study with the aim to evaluate the impact of prenatal exposure to volatile organic compounds and nitrogen oxides on lung function measured by oscillation tests. The preschoolers were followed until 5 years of age. Anthropometric measurements and forced oscillation tests were performed at 36, 48, and 60 months of age. Information on sociodemographic and health characteristics was obtained during follow up. Prenatal exposure to volatile organic compounds and nitrogen oxides was evaluated using a land use regression models and the association between them was tested using a lineal regression and longitudinal linear mixed effect models adjusting for potential confounders.

RESULTS

Overall, the mean (standard deviation) of the measurements of respiratory system resistance and respiratory system reactance at 6, 8, and 10 Hz during the follow-up period was 11.3 (2.4), 11.1 (2.4), 10.3 (2.2) and -5.2 (1.6), -4.8 (1.7), and -4.6 hPa s L^-1 (1.6), respectively. We found a significantly positive association between respiratory resistance (β_Rrs6  = 0.011; 95%CI: 0.001, 0.023) (P < .05) and prenatal exposure to nitrogen dioxide and a marginally negatively association between respiratory reactance (β_Xrs6  = -11.40 95%CI: -25.26, 1.17 and β_Xrs8  = -11.91 95%CI: -26.51, 1.43) (P = .07) and prenatal exposure to xylene.

CONCLUSION

Prenatal exposure to air pollutants was significantly associated with the alteration of lung function measured by oscillation tests in these preschool children.

Low lung function in the developing world is analogous to stunting: a review of the evidence

Background: Low vital capacity, one of the consequences of restricted lung growth, is a strong predictor of cardiovascular mortality. Vital capacity is lower in the developing world than the developed world, even after adjusting for height, weight and gender. This difference is typically dismissed as ethnic variation, adjusted for by redefining normal. Whether this is a consequence of stunted lung growth, rather than genetically smaller lungs, has not been investigated in detail. Therefore, we sought to compare factors implicated in both stunting and lung development, particularly in the developing world. Methods: We conducted a manual screen of articles identified through Google Scholar and assessed risk of bias. No language restrictions were applied, so long as there was an associated English abstract. We queried VizHub (Global Burden of Disease Visualization Tool) and Google Dataset search engines for disease burden and genome wide association studies.  The scope of the article and the heterogeneity of the outcome measures reported required a narrative review of available evidence. To the extent possible, the review follows PRISMA reporting guidelines. Results: Early life influences operate in synergism with environmental and nutritional factors to influence lung growth and development in children.  Low lung function and stunting have common anthropometric, environmental and nutritional correlates originating during early development. Similar anthropometric correlates and shared chronic inflammatory pathways indicated that the two conditions were analogous. Conclusion: The analogy between poor lung function and stunting is conspicuous in the developing world, where malnutrition lies at the center of non -achievement of growth potential, susceptibility to infectious diseases and intrauterine programming for metabolic syndrome. The common pathological mechanisms governing stunting and lung function deficits counter the idea of redefining the normal for lung function measurements.

Spatiotemporal Variations in Ambient Ultrafine Particles and the Incidence of Childhood Asthma

Rationale: Little is known regarding the impact of ambient ultrafine particles (UFPs; <0.1 μm) on childhood asthma development. Objectives: To examine the association between prenatal and early postnatal life exposure to UFPs and development of childhood asthma. Methods: A total of 160,641 singleton live births occurring in the City of Toronto, Canada between April 1, 2006, and March 31, 2012, were identified from a birth registry. Associations between exposure to ambient air pollutants and childhood asthma incidence (up to age 6) were estimated using random effects Cox proportional hazards models, adjusting for personal- and neighborhood-level covariates. We investigated both single-pollutant and multipollutant models accounting for coexposures to particulate matter ≤2.5 μm in aerodynamic diameter (PM_2.5) and NO₂. Measurements and Main Results: We identified 27,062 children with incident asthma diagnosis during the follow-up. In adjusted models, second-trimester exposure to UFPs (hazard ratio per interquartile range increase, 1.09; 95% confidence interval, 1.06-1.12) was associated with asthma incidence. In models additionally adjusted for PM_2.5 and nitrogen dioxide, UFPs exposure during the second trimester of pregnancy remained positively associated with childhood asthma incidence (hazard ratio per interquartile range increase, 1.05; 95% confidence interval, 1.01-1.09). Conclusions: This is the first study to evaluate the association between perinatal exposure to UFPs and the incidence of childhood asthma. Exposure to UFPs during a critical period of lung development was linked to the onset of asthma in children, independent of PM_2.5 and NO₂.

What is the impact of outdoor pollution on children's asthma?

Outdoor pollution is a complex mix of more than 200 air contaminants. Among these pollutants, ozone, nitrogen dioxide and fine particles may generate bronchial inflammation and hyperreactivity. The hypothesis that pollution contributes to the development of asthma in children is based on epidemiological, clinical and experimental data. Many risk factors during the in utero and postnatal period have been identified in the aetiology of childhood asthma. During pregnancy, outdoor pollution was identified as a causal factor of respiratory disease in neonatal cohort studies. Several epidemiological studies also demonstrate that outdoor pollution is a trigger of asthma exacerbations. This review aims to highlight the current knowledge on outdoor pollution and asthma.

Traffic-related Air Pollution, Lung Function, and Host Vulnerability. New Insights from the PARIS Birth Cohort

RATIONALE

Although the effects of traffic-related air pollution on respiratory exacerbations have been well documented, its impact on lung function in childhood remains unclear.

OBJECTIVES

Our aim was to investigate the associations of prenatal, early, and lifetime traffic-related air pollution exposure with lung function at 8-9 years studying possible effect modification by sex, sensitization at 8-9 years, and early lower respiratory tract infections.

METHODS

We conducted this study among 788 children from the PARIS (Pollution and Asthma Risk: an Infant Study) birth cohort. Lung function tests were performed during the medical examination at 8-9 years. Traffic-related air pollution exposure during each trimester of pregnancy was estimated using nitrogen oxides background measurements. Postnatal traffic-related air pollution exposure was assessed by a nitrogen oxides air dispersion model at both residential and daycare/school addresses. Associations between lung function and traffic-related air pollution exposure were analyzed by multiple linear regression models.

RESULTS

Higher prenatal nitrogen oxides levels, especially during the second trimester of pregnancy, were associated with a lower forced expiratory flow at 25-75% of the forced vital capacity, but there were no significant associations between prenatal nitrogen oxide levels and forced vital capacity, forced expiratory volume during 1 second, or the forced expiratory volume during 1 second/forced vital capacity ratio overall. Postnatal traffic-related air pollution exposure was associated with lower lung function among children with early lower respiratory tract infections or sensitization at 8-9 years, but not in the full cohort. In children with early repeated lower respiratory tract infections, an interquartile increase in lifetime nitrogen oxides exposure was associated with both a lower forced expiratory volume during 1 second (-62.6 ml; 95% confidence interval = -107.0 to -18.1) and forced vital capacity (-55.7 ml; 95% confidence interval = -109.5 to -1.8), but was not associated with the forced expiratory volume during 1 second/forced vital capacity ratio. There was an association between greater early postnatal nitrogen oxide exposure and a lower forced expiratory volume during 1 second/forced vital capacity ratio among sensitized children (-0.65%; 95% confidence interval = -1.25 to -0.05).

CONCLUSIONS

This study sheds new light, suggesting associations between postnatal traffic-related air pollution exposure and reduced lung function may be enhanced by early, repeated lower respiratory tract infections or allergic sensitization.

Exposure to moderate air pollution and associations with lung function at school-age: A birth cohort study

BACKGROUND

Adverse effects of higher air pollution levels before and after birth on subsequent lung function are often reported in the literature. We assessed whether low-to-moderate levels of air pollution during preschool-age impact upon lung function at school-age.

METHODS

In a prospective birth cohort of 304 healthy term-born infants, 232 (79%) completed lung function at follow-up at six years. Using spatial-temporal models, levels of individual air pollution (nitrogen dioxide (NO₂) and ozone (O₃), particulate matter with a diameter <10 μm (PM₁₀)) were estimated for the time windows pregnancy, first up to the sixth year of life separately, and birth until follow-up at six years. Time window means were compared to World Health Organization (WHO) guideline limits. Associations of exposure windows with spirometry and body plethysmography indices were analyzed using regression models, adjusting for potential confounders. For subgroup analysis, air pollution exposure was categorized into quartiles (four groups of 52 children).

RESULTS

Mean NO₂ level from birth until follow-up was [mean (range)] [11.8 (4.9 to 35.9 μg/m³)], which is almost 4-times lower than the WHO suggested limit of 40 μg/m³. In the whole population, increased air pollution levels from birth until follow-up were associated with reduced lung function at six years. In the subgroup analysis, the 52 children exposed to NO₂ levels from the highest quartile during pregnancy, the first and second years of life and from birth until follow-up, had a significant decrease in forced expiratory volume in 1 s (FEV₁). Per interquartile range increase of NO₂, FEV₁ decreased by [z-score change (95% confidence interval)] [-1.07 (-1.67 to -0.47)], [-1.02 (-1.66 to -0.39)], [-0.51 (-0.86 to -0.17)] and [-0.80 (-1.33 to -0.27)], respectively. Air pollution exposure during pregnancy and childhood resulted in a non-significant decrease in lung volume at six years, as assessed by functional residual capacity measured by body plethysmography (FRC_pleth).

CONCLUSION

Our results suggest that exposure to higher NO₂ levels, which are still much lower than WHO guideline limits, especially during the sensitive period of early lung development, may be associated with reduced lung function at school-age. These findings support the concept of age and dose-dependent pollution effects on lung function in healthy school-aged children and underline the importance of pollution reduction measures.

Factors associated with parent-reported wheeze and cough in children living in an industrial area of Gauteng, South Africa

We examined the factors associated with mother-reported wheeze and dry cough in children living in Tembisa, a residential and industrial community in South Africa. A cross-sectional sample of parents reported wheezing and dry cough in children (aged 1 to 26 months) by completing the standardised International Study of Asthma and Allergies in Childhood questionnaire with additional questions concerning tobacco use, income, living conditions, and mothers' educational level. Data were analysed using chi-square, univariate, and multivariable logistic regressions. Of the 493 children who participated, 81 (16.4%) had wheeze ever and 186 (37.7%) had dry cough ever. We observed that children had a higher probability of wheezing if mothers had lived in the area for longer periods (aOR 1.05; 95% CI 1.01-1.08). Children who had trucks passing on their streets frequently were more likely to have had dry cough ever compared to those with no trucks passing on their streets (aOR 3.88; 95% CI 2.29-6.57). In Tembisa, dry cough in a child was associated with the frequency of trucks passing in front of the child's home. Children were also more likely have wheeze if their mothers had been living in the community for longer times.

Lung function growth trajectories in non-asthmatic children aged 4-9 in relation to prenatal exposure to airborne particulate matter and polycyclic aromatic hydrocarbons - Krakow birth cohort study

BACKGROUND

Patterns of lung function development during childhood can be helpful in understanding the pathogenesis of respiratory diseases. A variety of environmental and lifestyle factors, present from the prenatal period to adulthood, may affect or modulate lung function growth. The aim of this study was to investigate, the associations between individual growth trajectories of children's lung function during childhood and prenatal exposure to airborne fine particulate matter (PM_2.5) and polycyclic aromatic hydrocarbons (PAH), which were hypothesized to adversely affect spirometry parameters.

MATERIAL AND METHODS

The study group comprised 294 non-asthmatic, full term children from the Krakow birth cohort, who underwent annual spirometry testing at the ages of 4-9 years. Individual personal air monitoring of PM_2.5 and PAH were performed over 48 h in the second trimester of pregnancy. Possible confounders or modifiers such as child's gender, height, atopic status and exposure to environmental tobacco smoke (ETS) were considered. Polynomial multilevel mixed models were used to assess the growth rates of children's lung functions.

RESULTS

Lung function trajectories differed significantly for boys and girls for FVC, FEV1 and FEF25-75. Girls had lower rates of increase than boys: - 20.5 (95%CI: - 32.4; - 8.6) ml/year (FVC); - 19.9 (95%CI: -30.7;-9.0) ml/year (FEV1); and - 32.5 (95%CI: - 56.9; - 8.2) ml/year (FEF25-75). Spirometry functions increased with age; however the growth rate decelerated over time. Significant lung function impairment (lower FVC and FEV1 levels) was observed from 4 to 9 years among subjects prenatally exposed to higher levels of PM_2.5 as well as PAH, but not in the case of FEF25-75. No significant differences were observed in the rates of increase over time in relation to prenatal PM_2.5 and PAH exposure.

CONCLUSION

Our results indicate that in non-asthmatic children high prenatal exposure to airborne PM_2.5 and PAH is associated with lower trajectories of FVC and FEV1, but not the rate of increase over time, suggesting that the initial effect is not diminishing in time.

Maternal exposure to PM2.5 in south Texas, a pilot study

In this study, we characterized personal exposure to fine particulate matter (PM_2.5), black carbon (BC), and nicotine in pregnant women in Hidalgo County, where the hospitalization rates of childhood asthma are the highest in the state of Texas. The measurements were conducted over three non-consecutive sampling days for 17 participants in their third trimester. Measurements were partitioned into four microenvironments, i.e., Residential, Vehicular, Commercial, and Other, on the basis of GPS coordinates and temperature and humidity measurements. The daily average PM_2.5 mass concentration was 24.2 (standard deviation=22.0) μg/m³, with the highest daily mass concentration reaching 126.0μg/m³. The daily average BC concentration was 1.44 (SD=0.82) μg/m³, ranging from 0.5 to 5.4μg/m³. Hair nicotine concentrations were all near the detection level (i.e., 49.2pg/mg), indicating that the participants were not routinely exposed to tobacco smoke. The Residential microenvironment contributed dominantly to the mass concentration since the participants chiefly remained at home and cooking activities contributed significantly to the total PM_2.5. When compared to an ambient monitoring station, the person-specific PM_2.5 was frequently more than double the ambient measurement (10.4μg/m³ overall), revealing that even in regions where ambient concentrations are below national standards, individuals may be still be exposed to elevated PM_2.5 mass concentrations.

Maternal exposure to particulate matter alters early post-natal lung function and immune cell development

BACKGROUND

In utero exposure to particulate matter (PM) from a range of sources is associated with adverse post-natal health; however, the effect of maternal exposure to community-sampled PM on early post-natal lung and immune development is poorly understood.

OBJECTIVES

Using a mouse model, we aimed to determine whether in utero exposure to PM alters early post-natal lung function and immune cell populations. We used PM collected from ceiling voids in suburban houses as a proxy for community PM exposure.

METHODS

Pregnant C57BL/6 mice were intranasally exposed to ceiling derived PM, or saline alone, at gestational day (E) 13.5, 15.5, and 17.5. When mice were two weeks old, we assessed lung function by the forced oscillation technique, and enumerated T and B cell populations in the spleen and thymus by flow cytometry.

RESULTS

Maternal exposure to PM impaired somatic growth of male offspring resulting in reduced lung volume and deficits in lung function. There was no effect on thymic T cell populations in dams and their male offspring but PM decreased the CD4 +CD25 + T cell population in the female offspring. In contrast, maternal exposure to PM increased splenic CD3 +CD4 + and CD3 +CD8 + T cells in dams, and there was some evidence to suggest inhibition of splenic T cell maturation in male but not female offspring.

CONCLUSIONS

Our findings suggested that maternal exposure to ceiling void PM has the capacity to impair early somatic growth and alter early life immune development in a sex specific manner.

Air pollutants and early origins of respiratory diseases

Air pollution is a global health threat and causes millions of human deaths annually. The late onset of respiratory diseases in children and adults due to prenatal or perinatal exposure to air pollutants is emerging as a critical concern in human health. Pregnancy and fetal development stages are highly susceptible to environmental exposure and tend to develop a long-term impact in later life. In this review, we briefly glance at the direct impact of outdoor and indoor air pollutants on lung diseases and pregnancy disorders. We further focus on lung complications in later life with early exposure to air pollutants. Epidemiological evidence is provided to show the association of prenatal or perinatal exposure to air pollutants with various adverse birth outcomes, such as preterm birth, lower birth weight, and lung developmental defects, which further associate with respiratory diseases and reduced lung function in children and adults. Mechanistic evidence is also discussed to support that air pollutants impact various cellular and molecular targets at early life, which link to the pathogenesis and altered immune responses related to abnormal respiratory functions and lung diseases in later life.

Lifetime exposure to particulate air pollutants is negatively associated with lung function in non-asthmatic children

BACKGROUND

Pulmonary function is known to be affected by acute and subacute exposure to ambient air pollution. However, the impacts of lifetime exposure to air pollution on the pulmonary function of children have been inconsistent. The present study investigated the impact of lifetime residential exposure to intermediate levels of air pollution on the pulmonary function of schoolchildren.

METHODS

In 2011, a survey of children aged 6-15 years was conducted in 44 schools in Taiwan. Atopic history, residential history, and environmental factors were recorded. Spirograms were obtained from a random sample of children without asthma. A total of 535 girls and 481 boys without a history of asthma were enrolled. Lifetime residential exposure to air pollutants, including particulate matter with an aerodynamic diameter less than 10 μm (PM₁₀), ozone (O₃), sulfur dioxide (SO₂), nitrogen dioxide (NO₂), and carbon monoxide (CO), was estimated using the kriging method, based on monitored data from the Taiwan Environmental Protection Administration. Multiple linear regression was used to analyze the association between lifetime air pollution exposure and pulmonary function, after adjustment for potential confounders and recent exposure.

RESULTS

After adjustment for 7-day average air pollutant levels, a 10 μg/m³ increase in PM₁₀ was related to reductions in the forced expiratory volume in 1 s (-2.00%; 95% confidence interval [CI] -3.09% to -0.90%), forced vital capacity (-1.86%; CI: -2.96% to -0.75%), and maximal midexpiratory flow (-2.28%; CI: -4.04% to -0.51%). These associations were independent of the other pollutants.

CONCLUSION

Lifetime exposure to 25-85 μg/m³ of PM₁₀ has negative impacts on the pulmonary function of children.

Local- and regional-scale air pollution modelling (PM10) and exposure assessment for pregnancy trimesters, infancy, and childhood to age 15 years: Avon Longitudinal Study of Parents And Children (ALSPAC)

We established air pollution modelling to study particle (PM₁₀) exposures during pregnancy and infancy (1990-1993) through childhood and adolescence up to age ~15 years (1991-2008) for the Avon Longitudinal Study of Parents And Children (ALSPAC) birth cohort. For pregnancy trimesters and infancy (birth to 6 months; 7 to 12 months) we used local (ADMS-Urban) and regional/long-range (NAME-III) air pollution models, with a model constant for local, non-anthropogenic sources. For longer exposure periods (annually and the average of birth to age ~8 and to age ~15 years to coincide with relevant follow-up clinics) we assessed spatial contrasts in local sources of PM₁₀ with a yearly-varying concentration for all background sources. We modelled PM₁₀ (μg/m³) for 36,986 address locations over 19 years and then accounted for changes in address in calculating exposures for different periods: trimesters/infancy (n = 11,929); each year of life to age ~15 (n = 10,383). Intra-subject exposure contrasts were largest between pregnancy trimesters (5^th to 95^th centile: 24.4-37.3 μg/m³) and mostly related to temporal variability in regional/long-range PM₁₀. PM₁₀ exposures fell on average by 11.6 μg/m³ from first year of life (mean concentration = 31.2 μg/m³) to age ~15 (mean = 19.6 μg/m³), and 5.4 μg/m³ between follow-up clinics (age ~8 to age ~15). Spatial contrasts in 8-year average PM₁₀ exposures (5^th to 95^th centile) were relatively low: 25.4-30.0 μg/m³ to age ~8 years and 20.7-23.9 μg/m³ from age ~8 to age ~15 years. The contribution of local sources to total PM₁₀ was 18.5%-19.5% during pregnancy and infancy, and 14.4%-17.0% for periods leading up to follow-up clinics. Main roads within the study area contributed on average ~3.0% to total PM₁₀ exposures in all periods; 9.5% of address locations were within 50 m of a main road. Exposure estimates will be used in a number of planned epidemiological studies.

Effect modification of perinatal exposure to air pollution and childhood asthma incidence

Perinatal exposure to ambient air pollution has been associated with childhood asthma incidence, however, less is known regarding the potential effect modifiers in this association. We examined whether maternal and infant characteristics modified the association between perinatal exposure to air pollution and development of childhood asthma.761 172 births occurring between 2006 and 2012 were identified in the province of Ontario, Canada. Associations between exposure to ambient air pollutants and childhood asthma incidence (up to age 6) were estimated using Cox regression models.110,981 children with asthma were identified. In models adjusted for postnatal exposures, second trimester exposures to particulate matter with a diameter ≤2.5 μm (PM2.5) (Hazard Ratio (HR) per interquartile (IQR) increase=1.07, 95% CI: 1.06-1.09) and nitrogen dioxide (NO2) (HR per IQR increase=1.06, 95% CI: 1.03-1.08) were associated with childhood asthma development. Enhanced impacts were found among children born to mothers with asthma, those who smoked during pregnancy, boys, those born preterm, of low birth weight and among those born to mothers living in urban areas during pregnancy.Prenatal exposure to air pollution may have a differential impact on the risk of asthma development according to maternal and infant characteristics.

Ultrafine, fine, and black carbon particle concentrations in California child-care facilities

Although many U.S. children spend time in child care, little information exists on exposures to airborne particulate matter (PM) in this environment, even though PM may be associated with asthma and other respiratory illness, which is a key concern for young children. To address this data gap, we measured ultrafine particles (UFP), PM_2.5 , PM₁₀ , and black carbon in 40 California child-care facilities and examined associations with potential determinants. We also tested a low-cost optical particle measuring device (Dylos monitor). Median (interquartile range) concentrations for indoor UFP, gravimetric PM_2.5 , real-time PM_2.5 , gravimetric PM₁₀ , and black carbon over the course of a child-care day were 14 000 (11 000-29 000) particles/cm³ , 15 (9.6-21) μg/m³ , 15 (11-23) μg/m³ , 48 (33-73) μg/m³ , and 0.43 (0.25-0.65) ng/m³ , respectively. Indoor black carbon concentrations were inversely associated with air exchange rate (Spearman's rho = -.36) and positively associated with the sum of all Gaussian-adjusted traffic volume within a one-kilometer radius (Spearman's rho = .45) (P-values <.05). Finally, the Dylos may be a valid low-cost alternative to monitor PM levels indoors in future studies. Overall, results indicate the need for additional studies examining particle levels, potential health risks, and mitigation strategies in child-care facilities.

Asthma disease as cause of admission to hospitals due to exposure to ambient oxidants in Mashhad, Iran

Nowadays, asthma is one of the most common chronic respiratory diseases, worldwide. Many reports have emphasized the correlation between the short-term exposure to the ambient air pollutants and acute respiratory diseases, especially among children with asthmatic symptoms. The aim of this study was to evaluate the relationship between the exposure to three atmospheric antioxidants (NO₂, SO₂, and O₃) and hospital admission due to asthmatic disease (HAAD) in the city of Mashhad, Iran. The concentrations of atmospheric antioxidants were obtained from the real-time monitoring stations located in the city. The collected data were employed for developing predictive models in the AirQ software. In order to investigate the association between short-term exposure to air pollutants and HAAD, the study participants were categorized into two age groups: less than 15 and from 15 to 64 years old. The results indicated that in people less than 15 years increase in NO₂ (attributable proportion (AP) = 3.775%, 95% CI 0.897-6.883%), SO₂ (AP = 3.649%, 95% CI 1.295-5.937%), and O₃ (AP = 0.554%,95% CI 0.00-3.321) results in increase in HAAD. While for those aged between 15 and 64 years, the AP was 4.192% (95% CI 0.450-7.662%) for NO₂; 0.0% (95% CI 0.00-1.687%) for SO₂; and 0.236% (95% CI 0.00-1.216%) for O₃. The number of asthmatic cases who were less than 15 years admitted to the hospitals during the study period was higher than that of those within the age groups between 15 and 64 years as a consequence of exposure to NO₂ (101 vs. 75), SO₂ (98 vs. 0), and O₃ (15 vs. 3), respectively. To the best of our knowledge, the AirQ model has not been applied before to estimate the effect of atmospheric antioxidant exposure on hospital admission because of asthma disease. Eventually, this model is proposed to be applicable for other cities around the world.

Maternal Exposure of BALB/c Mice to Indoor NO2 and Allergic Asthma Syndrome in Offspring at Adulthood with Evaluation of DNA Methylation Associated Th2 Polarization

BACKGROUND

Fetal stress has been proposed to be associated with diseases in both children and adults. Epidemiological studies suggest that maternal exposure to nitrogen dioxide (NO2) contributes to increased morbidity and mortality of offspring with allergic asthma later in life.

OBJECTIVES

We aimed to test whether maternal NO2 exposure causes allergic asthma-related consequences in offspring absent any subsequent lung provocation and whether this exposure enhances the likelihood of developing allergic asthma or the intensity of developed allergic airway disease following postnatal allergic sensitization and challenge. In addition, if such consequences and enhancements occurred, we sought to determine the mechanism(s) of these responses.

METHODS

Pregnant BALB/c mice were exposed to either NO2 (2.5 ppm, 5 h/day) or air daily throughout the gestation period. Offspring were sacrificed on postnatal days (PNDs) 1, 7, 14, 21, and 42, and remaining offspring were sensitized by ovalbumin (OVA) injection followed by OVA aerosol challenge during postnatal wk 7-9. We analyzed the lung histopathology, inflammatory cell infiltration, airway hyper-responsiveness (AHR), immune responses, and gene methylation under different treatment conditions.

RESULTS

Maternal exposure to NO2 caused a striking increase in inflammatory cell infiltration and the release of type 2 cytokines in the lungs of offspring at PNDs 1 and 7; however, these alterations were reversed during postnatal development. Following OVA sensitization and challenge, the exposure enhanced the levels of allergic asthma-characterized OVA-immunoglobulin (Ig) E, AHR, and airway inflammation in adult offspring. Importantly, differentiation of T-helper (Th) 2 cells and demethylation of the interleukin-4 (IL4) gene occurred during the process.

CONCLUSIONS

Maternal exposure to indoor environmental NO2 causes allergic asthma-related consequences in offspring absent any subsequent lung provocation and potentiates the symptoms of allergic asthma in adult offspring following postnatal allergic sensitization and challenge; this response is associated with the Th2-based immune response and DNA methylation of the IL4 gene. https://doi.org/10.1289/EHP685.

Air pollution during pregnancy and lung development in the child

Air pollution exposure has increased extensively in recent years and there is considerable evidence that exposure to particulate matter can lead to adverse respiratory outcomes. The health impacts of exposure to air pollution during the prenatal period is especially concerning as it can impair organogenesis and organ development, which can lead to long-term complications. Exposure to air pollution during pregnancy affects respiratory health in different ways. Lung development might be impaired by air pollution indirectly by causing lower birth weight, premature birth or disturbed development of the immune system. Exposure to air pollution during pregnancy has also been linked to decreased lung function in infancy and childhood, increased respiratory symptoms, and the development of childhood asthma. In addition, impaired lung development contributes to infant mortality. The mechanisms of how prenatal air pollution affects the lungs are not fully understood, but likely involve interplay of environmental and epigenetic effects. The current epidemiological evidence on the effect of air pollution during pregnancy on lung function and children's respiratory health is summarized in this review. While evidence for the adverse effects of prenatal air pollution on lung development and health continue to mount, rigorous actions must be taken to reduce air pollution exposure and thus long-term respiratory morbidity and mortality.

Gestational diabetes is associated with changes in placental microbiota and microbiome

BACKGROUND

The human microbiota is a modulator of the immune system. Variations in the placental microbiota could be related with pregnancy disorders. We profiled the placental microbiota and microbiome in women with gestational diabetes (GDM) and studied its relation to maternal metabolism and placental expression of anti-inflammatory cytokines.

METHODS

Placental microbiota and microbiome and expression of anti-inflammatory cytokines (IL10, TIMP3, ITGAX, and MRC1MR) were analyzed in placentas from women with GDM and from control women. Fasting insulin, glucose, O'Sullivan glucose, lipids, and blood cell counts were assessed at second and third trimester of pregnancy.

RESULTS

Bacteria belonging to the Pseudomonadales order and Acinetobacter genus showed lower relative abundance in women with GDM compared to control (P < 0.05). In GDM, lower abundance of placental Acinetobacter associated with a more adverse metabolic (higher O'Sullivan glucose) and inflammatory phenotype (lower blood eosinophil count and lower placental expression of IL10 and TIMP3) (P < 0.05 to P = 0.001). Calcium signaling pathway was increased in GDM placental microbiome.

CONCLUSION

A distinct microbiota profile and microbiome is present in GDM. Acinetobacter has been recently shown to induce IL-10 in mice. GDM could constitute a state of placental microbiota-driven altered immunologic tolerance, making placental microbiota a new target for therapy in GDM.

Exposure to outdoor air pollution during trimesters of pregnancy and childhood asthma, allergic rhinitis, and eczema

BACKGROUND

Mounting evidence suggests that exposure to ambient air pollution is associated with the development of childhood allergic diseases, but the effect of prenatal exposure to air pollution on the risk of childhood asthma and allergy is unclear.

OBJECTIVES

We evaluated the association between maternal exposure to outdoor air pollution during different trimesters of pregnancy and incidence of asthma, allergic rhinitis, and eczema in 2598 preschool children aged 3-6 years in China.

METHODS

Children's lifetime incidence of allergic diseases was obtained using questionnaire. Individual exposure to outdoor air pollutants during trimesters of pregnancy was estimated by an inverse distance weighted (IDW) method based on the measured concentrations at monitoring stations. We used multiple logistic regression method to estimate the odds ratio (OR) of asthma, allergic rhinitis, and eczema for per interquartile range (IQR) increase in the exposure to air pollutant in each trimester, which was adjusted for the effect of other air pollutants and its effect in other trimesters by a multi-pollutant/trimester model.

RESULTS

Incidence of asthma (6.8%), allergic rhinitis (7.3%), and eczema (28.6%) in children was associated with maternal exposure to traffic-related pollutant NO2 during entire pregnancy with OR (95% confidence interval [CI]) respectively 1.63 (0.99-2.70), 1.69 (1.03-2.77), and 1.37 (1.04-1.80). After adjustment for other pollutants and trimesters, we found the association was significant only in specific trimester: the first trimester for eczema (1.54, 1.14-2.09), the second trimester for asthma (1.72, 1.02-2.97), and the third trimester for allergic rhinitis (1.77, 1.09-2.89). Sensitivity analysis indicated that the trimester sensitive to the development of allergic diseases was stable.

CONCLUSION

Maternal exposure to traffic-related air pollutant NO2 during pregnancy, especially in specific trimesters, is associated with an increased risk of developing asthma, rhinitis, and eczema in children. Our results support the hypothesis that childhood allergic diseases originate in fetal life and are triggered by traffic-related air pollution in sensitive trimesters.

Preconceptional, prenatal and postnatal exposure to outdoor and indoor environmental factors on allergic diseases/symptoms in preschool children

BACKGROUND

Environmental factors have been found to be associated with allergic diseases, but it is unclear which environmental factor during which exposure window causes what kind of allergic diseases.

OBJECTIVES

We investigated association between exposure to some predominant outdoor and indoor environmental factors during preconceptional, prenatal, and postnatal periods and allergic diseases/symptoms in 2598 children in China.

METHODS

Children's lifetime incidence of allergic diseases and current prevalence of allergic symptoms and exposure to indoor new furniture/redecoration and mold/dampness was surveyed by a questionnaire. Exposure to outdoor air pollutants was estimated by the concentrations measured at air quality monitoring stations. Multiple logistic regression model was used to evaluate the associations between outdoor air pollutants and indoor environmental factors and allergic diseases (asthma, allergic rhinitis, and eczema) and symptoms (wheezing, night cough, and rhinitis-like).

RESULTS

We found that preconceptional, prenatal, and postnatal exposure to outdoor industrial and traffic air pollutants were significantly associated with increase in the risk of childhood asthma, and also positively associated with allergic rhinitis and eczema. However, we cannot distinguish the effect of outdoor air pollutants and exposure windows because of their high correlations. New furniture was associated with eczema and allergic rhinitis during postnatal exposure, but redecoration associated with asthma and eczema during prenatal exposure. Indoor visible mold/damp stains was significant for eczema during prenatal exposure and asthma during postnatal exposure respectively, but window condensation was significant for all childhood allergic diseases during both prenatal and postnatal exposures. Allergic symptoms in children were found to be associated with exposure to indoor factors only.

CONCLUSIONS

Associations between outdoor air pollutants and indoor environmental factors and childhood allergic diseases/symptoms were divergent and related to the timing of exposure.

Volatile organic compounds and particulate matter in child care facilities in the District of Columbia: Results from a pilot study

BACKGROUND

Many young children in the U.S. spend a significant portion of their day in child care facilities where they may be exposed to contaminants linked to adverse health effects. Exposure data on volatile organic compounds (VOCs) and particulate matter (PM) in these settings is scarce.

OBJECTIVE

To guide the design of a larger exposure assessment study in urban child care facilities, we conducted a pilot study in which we characterized indoor concentrations of select VOCs and PM.

METHODS

We recruited 14 child care facilities in the District of Columbia (Washington, DC) and measured indoor concentrations of seven VOCs (n=35 total samples; 2-5 samples per facility): benzene, carbon tetrachloride, chloroform, ethylbenzene, o-xylene, p-xylene, and toluene in all facilities; and collected real-time PM measurements in seven facilities. We calculated descriptive statistics for contaminant concentrations and computed intraclass correlation coefficients (ICC) to evaluate the variability of VOC levels indoors. We also administered a survey to collect general health information on the children attending these facilities, and information on general housekeeping practices and proximity of facilities to potential sources of target contaminants.

RESULTS

We detected six of the seven VOCs in the majority of child care facilities with detection frequencies ranging from 71% to 100%. Chloroform and toluene were detected in all samples. Median (range) concentrations for toluene, chloroform, benzene, o-xylene, ethylbenzene, and carbon tetrachloride were: 5.6µg/m(3) (0.6-16.5µg/m(3)), 2.8µg/m(3) (0.4-53.0µg/m(3)), 1.4µg/m(3) (below the limit of detection or <LOD - 4.4µg/m(3)), 1.1µg/m(3) (<LOD - 35.7µg/m(3)), 1.0µg/m(3) (<LOD - 28.5µg/m(3)), and 1.0µg/m(3) (<LOD - 1.6µg/m(3)), respectively. The ICCs for the VOCs measured ranged from 0.32 to 0.75. Child care facility median concentrations for PM2.5 and PM10 were 20.1µg/m(3) and 26.3µg/m(3), respectively. Chlorine bleach, a source of chloroform, was used in almost all facilities, air fresheners and/or scented candles were used in half of the facilities, and at least one child in each facility had physician-diagnosed asthma (median asthma prevalence rate=10.2%).

CONCLUSION

We found quantifiable levels of VOCs and PM in the child care facilities sampled. Given that exposures to environmental contaminants during critical developmental stages may have long lasting impacts on children's health, larger studies are needed to characterize and identify sources of exposures to these and other indoor contaminants to develop exposure mitigation strategies.