Early life exposure to air pollution: how bad is it?

The association of prenatal ambient air pollution with placental epigenetic gestational age at birth

Background

Prenatal air pollutants have been associated with adverse birth outcomes, and DNA methylation (DNAm) changes in placenta may contribute to these associations. DNAm-based epigenetic gestational age (GA) estimators are emerging biomarkers for aging/biological age that can reflect early-life exposures and predict long-term health outcomes. We leveraged 103 mother-offspring pairs from the Early Autism Risk Longitudinal Investigation cohort to assess associations between prenatal air pollution and placental epigenetic GA at birth.

Methods

Prenatal air pollution concentrations (NO2, O3, PM2.5, and PM10) were estimated from weekly data from monitoring stations near maternal residence and calculated for preconception and pregnancy periods. DNAm from fetal-side placenta samples was measured on Illumina HumanMethylation450 BeadChip. Epigenetic GA was computed using Lee's robust placenta clock algorithm. GA acceleration/deceleration was the residual of predicted epigenetic GA on chronologic GA, adjusted (intrinsic) or unadjusted (extrinsic) for cell type proportions. We used linear regressions to examine associations between average air pollution levels in each period and GA acceleration/deceleration, and weekly distributed lag models to examine critical exposure windows.

Results

Higher pregnancy average O3 and PM10 exposures were associated with decelerated intrinsic (β = -0.65 and -0.79) and extrinsic GA (β = -0.69 and -0.74) at birth (per 10-unit increment). Trimester-specific analyses revealed higher O3 and PM10 exposures in trimesters 2 to 3 associated with decelerated GA at birth. Weekly distributed lag models suggested pregnancy weeks 21 to 31 and 21 to 29 were critical windows of O3 and PM10 exposures, respectively.

Conclusions

Prenatal air pollution exposures, especially during mid- to late-pregnancy, were associated with lower biological maturity at birth.

Air pollution and preterm birth: comparing trimester average and repeated threshold exposure metrics in a North Carolina birth cohort, 2003-2015

BACKGROUND

Exposures to ambient air pollutants during pregnancy are associated with preterm birth (PTB) in studies that evaluate average pollutant concentrations during potential "windows of susceptibility," referred to as critical windows.

OBJECTIVE

We evaluated associations between ozone (O3) or particulate matter <2.5 micrometers (PM2.5) during pregnancy and PTB, using continuous and categorical metrics of average exposure and repeated exceedances of threshold concentrations.

METHODS

We analyzed data from North Carolina (NC) birth certificates from the NC Birth Defects Monitoring Program, limited to live, singleton births without birth defects and delivered from 2003-2015. The EPA's Fused Air Quality Surface Using Downscaling (fCMAQ) model was used to assign exposures for trimester-average and daily threshold exceedances for O3 (daily 8-h maximum) and PM2.5 (24-h average) at different daily threshold concentrations (O3: 55-70 ppb; PM2.5: 20-35 µg/m3) during trimesters 1 and 2 of pregnancy. Descriptive statistics, including weighted kappa statistics, were evaluated. Modified Poisson regression models were used to estimate adjusted risk differences (RDs) per 10,000 births.

RESULTS

Among the cohort of 1,368,370 births, 8.4% were PTBs. The number of daily exposure exceedances ranged from 0 to 81 days over different threshold concentrations during trimester 1 or 2. There was slight to moderate agreement in risk associated with trimester average and daily threshold exposures exceedances, with decreased agreement among higher threshold concentrations. RDs ranged from -31 to 29 for average O3 exposure and from -2 to 89 for repeated O3 threshold exceedances. RDs ranged from 23 to 120 for average PM2.5 exposure and from -227 to 118 for repeated PM2.5 exposure.

SIGNIFICANCE

This study provides insights into the heterogeneity in risk of PTB when assessing different air pollution exposure metrics.

IMPACT

This study investigates the impact of O3 and PM2.5 exposures during pregnancy on the risk of PTB, using measures based on both average concentrations and repeated exceedances of threshold levels. The findings address uncertainties identified in recent NAAQS reviews and suggests that repeated exposure metrics may capture differences in exposure that are not apparent when evaluating average exposure metrics.

Association analysis of maternal exposure to air pollution during pregnancy and offspring asthma incidence

BACKGROUND

Air pollution has a significant negative impact on human health. Pregnant mothers and children are typical susceptible groups, and environmental exposure has a crucial impact on children's health. We established a childhood asthma cohort to analyze the factors influencing the development of asthma in offspring, with a focus on prenatal exposure to air pollutants. The goal was to explore potential early preventive measures to reduce the incidence of childhood asthma.

METHODS

This nested case-control study included mothers who were registered and delivered at Lianyungang Maternal and Child Health Hospital between 2015 and 2018, covering pre-pregnancy, first, second, and third trimesters. Children diagnosed with asthma before the age of four were included in the asthma group. To assess environmental exposure, we gathered data from 29 national and provincial air pollution monitoring stations and 16 meteorological monitoring sites in Lianyungang and surrounding areas. We used spatial interpolation with inverse distance weighting (IDW) to estimate individual exposure to air pollutants, including particulate matter (PM2.5, PM10), carbon monoxide (CO), nitrogen dioxide (NO2), sulfur dioxide (SO2), and ozone (O3). Univariate and multivariate regression analyses were conducted to examine the association between maternal exposure during pregnancy and the risk of childhood asthma.

RESULTS

A total of 292 mother-child pairs in the asthma group and 1423 mother-child pairs in the healthy control group were included. The second (AOR = 1.04, 95%CI 1.01-1.06) and whole gestation (AOR = 1.06, 95%CI 1.03-1.10) exposure to PM2.5 was associated with higher odds of childhood-onset asthma. Exposure during the third trimester (AOR = 1.02, 95%CI 1.01-1.03) and whole gestation (AOR = 1.02, 95%CI 1.01-1.04) of PM10 was associated with higher odds of childhood-onset asthma. The first (AOR = 1.06, 95%CI 1.02-1.09) and second (AOR = 0.95, 95%CI 0.92-0.98) trimesters exposure to NO2 was associated with higher and lower odds of childhood-onset asthma, respectively. SO2 whole pregnancy exposure (AOR = 1.04, 95%CI 1.01-1.07) was associated with higher odds of childhood-onset asthma.

CONCLUSIONS

Exposure to PM2.5, PM10, and SO2 during pregnancy can lead to an elevated risk of childhood asthma. Reducing or avoiding exposure to pollutants during pregnancy can reduce the incidence of childhood asthma. We should protect the environment and reduce the harm of environmental pollution to health.

Association between prenatal air pollutant exposure and autism spectrum disorders in young children: A matched case-control study in Canada

The direction and magnitude of association between maternal exposure to ambient air pollutants across gestational windows and offspring risk of autism spectrum disorders (ASD) remains unclear. We sought to evaluate the time-varying effects of prenatal air pollutant exposure on ASD. We conducted a matched case-control study of singleton term children born in Ontario, Canada from 1-Apr-2012 to 31-Dec-2016. Provincial birth registry data were linked with applied behavioural analysis services and ambient air pollutant datasets to ascertain prenatal exposure to nitrogen dioxide (NO2), ground-level ozone (O3), fine particulate matter (PM2.5), and ASD diagnoses. Covariate balance between cases and controls was established using coarsened exact matching. Conditional logistic regression was used to assess the association between prenatal air pollutant exposure and ASD. Distributed lag non-linear models (DLNM) were used to examine the effects of single-pollutant exposure by prenatal week. Sensitivity analyses were conducted to assess the impact of exposure period on the observed findings. The final sample included 1589 ASD cases and 7563 controls. Compared to controls, cases were more likely to be born to mothers living in urban areas, delivered by Caesarean section, and assigned male sex at birth. NO2 was a consistent and significant contributor to ASD risk after accounting for co-exposure to O3, PM2.5 and covariates. The odds ratio per interquartile range increase was 2.1 (95%CI 1.8-2.3) pre-conception, 2.2 (2.0-2.5) for the 1st trimester, 2.2 (1.9-2.5) for the 2nd trimester, and 2.1 (1.9-2.4) for the 3rd trimester. In contrast, findings for O3 and PM2.5 with ASD were inconsistent. Findings from DLNM and sensitivity analyses were similar. Exposure to NO2 before and during pregnancy was significantly associated with ASD in offspring. The relationship between prenatal O3 and PM2.5 exposure and ASD remains unclear. Further investigation into the combined effects of multi-pollutant exposure on child neurodevelopment is warranted.

Associations of PM2.5 exposure with emergency department visits and readmissions among preterm infants with bronchopulmonary dysplasia

OBJECTIVES

To quantify the association of ambient air pollution (particulate matter, PM2.5) exposure with medically attended acute respiratory illness among infants with bronchopulmonary dysplasia (BPD).

STUDY DESIGN

Single center, retrospective cohort study of preterm infants with BPD in Metropolitan Philadelphia. Multivariable logistic regression quantified associations of annual mean PM2.5 exposure (per μg/m3) at the census block group level with medically attended acute respiratory illness, defined as emergency department (ED) visits or hospital readmissions within a year after first hospital discharge adjusting for age at neonatal intensive care unit (NICU) discharge, year, sex, race, insurance, BPD severity, and census tract deprivation. As a secondary analysis, we examined whether BPD severity modified the associations.

RESULTS

Of the 378 infants included in the analysis, 189 were non-Hispanic Black and 235 were publicly insured. Census block PM2.5 level was not significantly associated with medically attended acute respiratory illnesses, ED visits, or hospital readmissions in the full study cohort. We observed significant effect modification by BPD grade; each 1 µg/m3 higher annual PM2.5 exposure was medically attended acute respiratory illness (adjusted odds ratio [aOR] 1.65, 95% CI: 1.06-2.63) among infants with Grade 1 BPD but not among infants with grade 3 BPD (aOR 0.83, 95% CI: 0.47-1.48) (interaction p = .024).

CONCLUSIONS

Cumulative PM2.5 exposure in the year after NICU discharge was not significantly associated with medically attended acute respiratory illness among infants with BPD. However, infants with Grade 1 BPD had significantly higher odds with higher exposures. If replicated, these findings could inform anticipatory guidance for families of these infants to avoid outdoor activities during high pollution days after NICU discharge.

Long-term ambient sulfur dioxide exposure during gestation and preterm birth in North Carolina, 2003-2015

BACKGROUND

Coal-fired power plants are major contributors of ambient sulfur dioxide (SO2) air pollution. Epidemiological literature suggests an adverse association between SO2 exposure during gestation and preterm birth (PTB; <37 weeks completed gestation). PTB is strongly associated with infant mortality and increased risk for later life morbidities.

OBJECTIVE

We investigated associations between SO2 and PTB in North Carolina and evaluated whether the associations were modified by race/ethnicity.

METHODS

We assembled a retrospective, administrative cohort of singleton births in North Carolina from 2003-2015. We used US EPA EQUATES data to assign long-term SO2 gestational exposures to eligible births for the entire pregnancy and by trimester. We used multivariable generalized linear regression to estimate risk differences (RD (95%CI)) per 1-ppb increase in SO2, adjusted for gestational parent education, Medicaid status, marital status, and season of conception. Multi-pollutant models were additionally adjusted for other criteria air co-pollutants (O3, PM2.5, NO2).

RESULTS

The median SO2 (24-hour average) across exposure windows was ~1.5 (IQR: 1.8) ppb. The overall baseline risk for PTB was 8,756 per 100,000 live births. When stratified by race/ethnicity, the baseline risk for PTB was 12215, 7824, and 7187 per 100,000 live births among non-Hispanic Black, non-Hispanic white, and Hispanic births, respectively. RDs per 1-ppb increase in SO2 averaged across the entire pregnancy were 317.0 (95%CI: 279.4, 354.5) and 568.2 (95%CI: 500.3, 636.1) per 100,000 live births for single- and multi-pollutant models, respectively. For the PTB multi-pollutant models, we observed similar RDs for non-Hispanic Black participants (669.6 [95%CI: 573.9, 765.2]) and non-Hispanic white participants (635.4 [95%CI: 557.2, 713.6]) with smaller RDs for Hispanic participants (336.8 [95%CI: 241.3, 432.2]).

SIGNIFICANCE

The results for our adjusted single- and multi-pollutant models showed adverse associations between SO2 and PTB, with some evidence of effect measure modification by race/ethnicity within subcategories of PTB.

Prenatal PM2.5 Exposure and Its Association with Low Birth Weight: A Systematic Review and Meta-Analysis

Exposure to PM2.5 while pregnant is associated with negative effects on low birth weight (LBW). This study employed a systematic review and meta-analysis to investigate the impact of PM2.5 exposure during pregnancy on LBW. A search of databases such as Scopus, ScienceDirect, and PubMed identified thirteen appropriate studies. This study used a random-effects model to calculate pooled odds ratios (ORs) and 95% confidence intervals (CIs) for each trimester. The findings revealed a significant relationship between PM2.5 exposure and LBW in both the first and second trimesters (OR 1.05, 95% CI 1.00-1.09, p < 0.001). There was no significant difference between trimesters (p = 0.704). The results emphasize the persistent influence of PM2.5 on fetal development throughout all stages of pregnancy. Reducing air pollution is critical for improving pregnancy outcomes and decreasing the incidence of LBW. Further study is needed to improve exposure assessments and investigate the underlying biological pathways.

Exposure to urban ambient particles (PM2.5) before pregnancy affects the expression of endometrial receptive markers to embryo implantation in mice: Preliminary results

Air pollution (AP) is one of the main recent concerns in reproductive healthy due to its potential to promote negative outcomes during pregnancy and male and female fertility. Several studies have demonstrated that AP exposure has been linked to increased embryonic implantation failures, alterations in embryonic, fetal and placental development. For a well-succeeded implantation, both competent blastocyst and receptive endometrium are required. Based on the lack of data about the effect of AP in endometrial receptivity, this study aimed to evaluate he particulate matter (PM) exposure impact on uterine receptive markers in mice and associate the alterations to increased implantation failures due to AP. For this study, ten dams per group were exposed for 39 days to either filter (F) or polluted air (CAP). At fourth gestational day (GD4), females were euthanized. Morphological, ultrastructural, immunohistochemical and molecular analysis of uterine and ovarian samples were performed. CAP-exposed females presented a reduced number of corpus luteum; glands and epithelial cells were increased with pinopodes formation impairment. Immunohistochemistry analysis revealed decreased LIF protein levels. These preliminary data suggests that PM exposure may exert negative effects on endometrial receptivity by affecting crucial parameters to embryonic implantation as uterine morphological differentiation, corpus luteum quantity and LIF expression during implantation window.

Prenatal Exposure to Air Pollution and Respiratory Distress in Term Newborns: Results from the MIREC Prospective Pregnancy Cohort

BACKGROUND

Respiratory distress is the leading cause of neonatal morbidity and mortality worldwide, and prenatal exposure to air pollution is associated with adverse long-term respiratory outcomes; however, the impact of prenatal air pollution exposure on neonatal respiratory distress has not been well studied.

OBJECTIVES

We examined associations between prenatal exposures to fine particular matter (PM 2.5 ) and nitrogen dioxide (NO 2 ) with respiratory distress and related neonatal outcomes.

METHODS

We used data from the Maternal-Infant Research on Environmental Chemicals (MIREC) Study, a prospective pregnancy cohort (n = 2,001 ) recruited in the first trimester from 10 Canadian cities. Prenatal exposures to PM 2.5 (n = 1,321 ) and NO 2 (n = 1,064 ) were estimated using land-use regression and satellite-derived models coupled with ground-level monitoring and linked to participants based on residential location at birth. We calculated odds ratios (ORs) and 95% confidence intervals (CIs) for associations between air pollution and physician-diagnosed respiratory distress in term neonates in hierarchical logistic regression models adjusting for detailed maternal and infant covariates.

RESULTS

Approximately 7 % of newborns experienced respiratory distress. Neonates received clinical interventions including oxygen therapy (6%), assisted ventilation (2%), and systemic antibiotics (3%). Two percent received multiple interventions and 4% were admitted to the neonatal intensive care unit (NICU). Median PM 2.5 and NO 2 concentrations during pregnancy were 8.81   μ g / m 3 and 18.02  ppb , respectively. Prenatal exposures to air pollution were not associated with physician-diagnosed respiratory distress, oxygen therapy, or NICU admissions. However, PM 2.5 exposures were strongly associated with assisted ventilation (OR per 1 - μ g / m 3 increase in PM 2.5 = 1.17 ; 95% CI: 1.02, 1.35), multiple clinical interventions (OR per 1 - μ g / m 3 increase in PM 2.5 = 1.16 ; 95% CI: 1.07, 1.26), and systemic antibiotics, (OR per 1 - μ g / m 3 increase in PM 2.5 = 1.12 ; 95% CI: 1.04, 1.21). These associations were consistent across exposure periods-that is, during prepregnancy, individual trimesters, and total pregnancy-and robust to model specification. NO 2 exposure was associated with administration of systemic antibiotics (OR per 1-ppb increase in NO 2 = 1.03 ; 95% CI: 1.00, 1.06).

DISCUSSION

Prenatal exposures to PM 2.5 increased the risk of severe respiratory distress among term newborns. These findings support the development and prioritization of public health and prenatal care strategies to increase awareness and minimize prenatal exposures to air pollution. https://doi.org/10.1289/EHP12880.

Associations between congenital heart disease and air pollutants at different gestational weeks: a time-series analysis

Exposure to air pollution during pregnancy has been linked to birth defects. But the directions of studies on the associations between air pollutants exposure and effect on the incidence of congenital heart disease (CHDs) were inconsistent. To date, few studies were concentrated on the effects of both particulate matter and gaseous air pollutant exposure on CHDs across the full gestational week simultaneously. Our study aimed to investigate the critical exposure windows for each air pollutant throughout 40 gestational weeks. Data on CHDs, air pollution, and meteorological factors from 2013 to 2019 were collected in Lanzhou, China. A distributed lag nonlinear model combined with a quasi-Poisson regression model was applied to evaluate the weekly exposure-lag-response association between air pollutants levels and CHDs, and the subgroup analyses were conducted by gender (baby boy and baby girl). The study included 1607 mother-infant pairs. The results demonstrated that exposure of pregnant women to particulate matter ≤ 5 μm (PM_2.5) at lag 1-4 weeks was significantly associated with the risk of CHDs, and the strongest effects were observed in the lag 1 week (1.150, 95%CI 1.059-1.248). For exposure to particulate matter ≤ 10 μm (PM₁₀) at lag 1-3 weeks, the strongest effects were observed in the lag 1 week (1.075, 95% CI 1.026-1.128). For exposure to sulfur dioxide (SO₂) at lag 1-4 weeks, the strongest effects were observed in the lag 1 week (1.154, 95% CI 1.025-1.299). For exposure to carbon monoxide (CO) at lag 1-3 weeks, the strongest effects were observed in the lag 1 week (1.089, 95% CI 1.002-1.183). For exposure to ozone (O₃) concentration at lag 9-15 weeks, the strongest effects were observed in the lag 15 weeks (1.628, 95% CI 1.001-2.649). The cumulative effects of PM_2.5, PM₁₀, SO₂, and CO along weeks with a maximum of 1.609 (95%CI 1.000-2.589), 1.286 (95%CI 1.007-1.641), 1.648 (95%CI 1.018-2.668), and 1.368 (95%CI 1.003, 1.865), respectively. The effects were obvious in the initial gestational weeks too. Through the gender stratification analysis, the air pollutants with significant effects were PM_2.5 for baby boys and PM_2.5, PM₁₀, SO₂, CO, NO₂, and O₃ for baby girl. For the relationship between CHDs and air pollution in Lanzhou, PM_2.5, PM₁₀, SO₂, CO, and O₃ played an important role in the initial gestational weeks, especially for baby girl.

No association between in utero exposure to emissions from a coalmine fire and post-natal lung function

BACKGROUND AND OBJECTIVE

Studies linking early life exposure to air pollution and subsequent impaired lung health have focused on chronic, low-level exposures in urban settings. We aimed to determine whether in utero exposure to an acute, high-intensity air pollution episode impaired lung function 7-years later.

METHOD

We conducted a prospective cohort study of children who lived in the vicinity of a coalmine fire. Respiratory function was measured using the forced oscillation technique (FOT). Z-scores for resistance at 5 Hz (R₅), reactance at 5 Hz (X₅) and area under the reactance curve (AX) were calculated. Two sets of analyses were conducted to address two separate questions: (1) whether mine fire exposure (a binary indicator; conceived after the mine fire vs in utero exposed) was associated with the respiratory Z-scores; (2) whether there was any dose-response relationship between fire-related PM_2.5 exposure and respiratory outcomes among those exposed.

RESULTS

Acceptable lung function measurements were obtained from 79 children; 25 unexposed and 54 exposed in utero. Median (interquartile range) for daily average and peak PM_2.5 for the exposed children were 4.2 (2.6 - 14.2) and 88 (52-225) µg/m³ respectively. There were no detectable differences in Z-scores between unexposed and exposed children. There were no associations between respiratory Z-scores and in utero exposure to PM_2.5 (daily average or peak).

CONCLUSION

There was no detectable effect of in utero exposure to PM_2.5 from a local coalmine fire on post-natal lung function 7-years later. However, statistical power was limited.

Can Maternal Exposure to Air Pollution Affect Post-Natal Liver Development?

Emerging evidence suggests that inhalation of particulate matter (PM) can have direct adverse effects on liver function. Early life is a time of particular vulnerability to the effects of air pollution. On that basis, we tested whether in utero exposure to residential PM has an impact on the developing liver. Pregnant mice (C57BL/6J) were intranasally administered 100 µg of PM sampled from residential roof spaces (~5 mg/kg) on gestational days 13.5, 15.5, and 17.5. The pups were euthanized at two weeks of age, and liver tissue was collected to analyse hepatic metabolism (glycogen storage and lipid level), cellular responses (oxidative stress, inflammation, and fibrosis), and genotoxicity using a range of biochemical assays, histological staining, ELISA, and qPCR. We did not observe pronounced effects of environmentally sampled PM on the developing liver when examining hepatic metabolism and cellular response. However, we did find evidence of liver genomic DNA damage in response to in utero exposure to PM. This effect varied depending on the PM sample. These data suggest that in utero exposure to real-world PM during mid-late pregnancy has limited impacts on post-natal liver development.

Air Pollution: Possible Interaction between the Immune and Nervous System?

Exposure to environmental pollutants is a serious and common public health concern associated with growing morbidity and mortality worldwide, as well as economic burden. In recent years, the toxic effects associated with air pollution have been intensively studied, with a particular focus on the lung and cardiovascular system, mainly associated with particulate matter exposure. However, epidemiological and mechanistic studies suggest that air pollution can also influence skin integrity and may have a significant adverse impact on the immune and nervous system. Air pollution exposure already starts in utero before birth, potentially causing delayed chronic diseases arising later in life. There are, indeed, time windows during the life of individuals who are more susceptible to air pollution exposure, which may result in more severe outcomes. In this review paper, we provide an overview of findings that have established the effects of air pollutants on the immune and nervous system, and speculate on the possible interaction between them, based on mechanistic data.

Prenatal exposure to fine particulate matter and the risk of spontaneous preterm birth: A population-based cohort study of twins

BACKGROUND

Studies in singletons have suggested that prenatal exposure to fine particulate matter (PM2.5) and some of its chemical components is associated with an increased risk of preterm birth (PTB). However, no study has been conducted in twins.

PURPOSE

To examine the associations of maternal exposure to total PM2.5 mass and its carbonaceous components with PTB in twin pregnancies.

METHODS

A total of 1,515 pairs of twins and their mothers were enrolled from a previous twin birth cohort that had been conducted at the Shanghai First Maternity and Infant Hospital School of Medicine of Tongji University in China. Participants who had iatrogenic PTBs were excluded. Maternal exposure to total PM2.5 mass and two carbonaceous components, namely, organic carbon (OC) and black carbon (BC), was estimated by a satellite-based model. The associations between PM2.5 exposure and the risk of spontaneous PTB were evaluated by logistic regression analysis.

RESULTS

This study found that exposure to total PM2.5 mass and OC during the second trimester of pregnancy was significantly associated with an increased risk of spontaneous PTB. An interquartile range (IQR) increase in total PM2.5 mass and OC exposure during the second trimester was associated with 48% (OR = 1.48, 95% CI, 1.06, 2.05) and 50% (OR = 1.50, 95% CI, 1.00, 2.25) increases in the odds of PTB, respectively. However, no significant association was found between BC exposure during any exposure window and the risk of PTB.

CONCLUSION

The findings suggest that exposure to ambient air pollution with fine particles may be a risk factor for spontaneous PTB in twin pregnancies. The middle stage of pregnancy seems to be a critical window for the impacts of PM2.5 exposure on PTB in twin pregnancies.

Assessing exposure to household air pollution in children under five: A scoping review

Understanding the differences in the approaches used to assess household air pollution (HAP) is crucial for evaluating HAP-related health effects and interpreting the effectiveness of stove-fuel interventions. Our review aims to understand how exposure to HAP from solid fuels was measured in epidemiological studies in children under five. We conducted a search of PubMed, EMBASE, Cochrane Central Register of Controlled Trials, Global Health Library, Web of Science, and CINAHL to identify English-language research articles published between January 1, 2000 and April 30, 2022. Two researchers applied the inclusion and exclusion criteria independently. Study region, type of measurement, study design, health outcomes, and other key characteristics were extracted from each article and analyzed descriptively. Our search strategy yielded 2229 records, of which 185 articles were included. A large proportion was published between 2018 and 2022 (42.1%), applied a cross-sectional study design (47.6%), and took place in low- or lower middle-income countries. Most studies (130/185, 70.3%) assessed HAP using questionnaires/interviews, most frequently posing questions on cooking fuel type, followed by household ventilation and cooking location. Cooking frequency/duration and children's location while cooking was less commonly considered. About 28.6% (53/185) used monitors, but the application of personal portable samplers was limited (particulate matter [PM]: 12/40, 30.0%; carbon monoxide [CO]: 13/34, 38.2%). Few studies used biomarkers or modeling approaches to estimate HAP exposure among children under five. More studies that report household and behavioral characteristics and children's location while cooking, apply personal exposure samplers, and perform biomarker analysis are needed to advance our understandings of HAP exposure among infants and young children, who are particularly susceptible to HAP-related health effects.

Machine learning-based risk factor analysis of adverse birth outcomes in very low birth weight infants

This study aimed to analyze major predictors of adverse birth outcomes in very low birth weight (VLBW) infants including particulate matter concentration (PM10), using machine learning and the national prospective cohort. Data consisted of 10,423 VLBW infants from the Korean Neonatal Network database during January 2013-December 2017. Five adverse birth outcomes were considered as the dependent variables, i.e., gestational age less than 28 weeks, gestational age less than 26 weeks, birth weight less than 1000 g, birth weight less than 750 g and small-for-gestational age. Thirty-three predictors were included and the artificial neural network, the decision tree, the logistic regression, the Naïve Bayes, the random forest and the support vector machine were used for predicting the dependent variables. Among the six prediction models, the random forest had the best performance (accuracy 0.79, area under the receiver-operating-characteristic curve 0.72). According to the random forest variable importance, major predictors of adverse birth outcomes were maternal age (0.2131), birth-month (0.0767), PM10 month (0.0656), sex (0.0428), number of fetuses (0.0424), primipara (0.0395), maternal education (0.0352), pregnancy-induced hypertension (0.0347), chorioamnionitis (0.0336) and antenatal steroid (0.0318). In conclusion, adverse birth outcomes had strong associations with PM10 month as well as maternal and fetal factors.

Gestational and Neonatal Outcomes in Cities in the Largest Coal Mining Region in Brazil

Brazil has one of the largest mineral coal reserves in the world. More than 40% of this ore is in the Candiota Mine, in the extreme south of Brazil, which was previously identified as a hotspot of environmental pollution. In addition, an important part of Brazil's population suffers from socioeconomic vulnerability. Since there is no information on unfavorable gestational and neonatal outcomes associated with these problems, we conducted a cross-sectional study with 1950 mother-child binomials, aiming to evaluate the association between these outcomes and air pollution as well as socioeconomic, demographic and health variables in seven cities in the region. Of the total births, 11.6% were preterm and 9.5% of neonates had low birth weight (<2500 g). These conditions were also associated with skin color, previous abortions, birth type and prenatal care, as well as exposure to higher levels of coarse particulate matter (PM10) during the first trimester of pregnancy. Regarding air pollutants, although the daily limits for PM10 were exceeded on less than 5% of days, the annual average overtook the values proposed by WHO. Thus, we concluded that prematurity and low birth weight in this region are related to air pollution, and to socioeconomic variables and health care.

ROS-independent cytotoxicity of 9,10-phenanthrenequinone inhibits cell cycle progression and spindle assembly during meiotic maturation in mouse oocytes

Diesel exhaust particles (DEPs) are major components of ambient particulate matter and are associated with various adverse health effects. Typically, DEPs contain a vast number of organic compounds, among which 9,10-phenanthrenequinone (9,10-PQ), the quinone derivative of the polycyclic aromatic hydrocarbon phenanthrene, is one of the most abundant and toxic. 9,10-PQ can produce excessive reactive oxygen species (ROS) via redox cycling and exhibit cytotoxicity in various cells. However, the underlying mechanisms involved in cytotoxicity of 9,10-PQ remain elusive. In this study, we investigated the effects of exposure to 9,10-PQ using mouse oocytes as a model system. We found that 9,10-PQ compromised meiotic maturation by impairing acentriolar microtubule organizing center (MTOC) assembly and subsequent spindle formation during meiotic maturation. Moreover, 9,10-PQ exposure prevented cell cycle progression by inhibiting Cdk1 activation via disturbance of cyclin B1 accumulation. Importantly, meiotic defects induced by 9,10-PQ exposure were not rescued by decreasing ROS levels, revealing that 9,10-PQ has ROS-independent activity that regulates cell cycle progression and spindle assembly. Therefore, our findings reveal that 9,10-PQ has novel activity that regulates cell-cycle progression and spindle formation in an ROS-independent manner during meiotic maturation in mouse oocytes.

How Do Transportation Influencing Factors Affect Air Pollutants from Vehicles in China? Evidence from Threshold Effect

In recent years, China has promoted a series of legal norms to reduce the environmental impact of air pollutants from vehicles. The three main vehicle emission species (carbon monoxide, hydrocarbons, nitrogen oxides) contribute significantly to air pollution. In this study, the emission factor method was used to estimate air pollutants from vehicles in 31 provinces from 2006 to 2016. The results show a trend of total vehicle carbon monoxide (CO) and hydrocarbons (HC) emissions decreasing with time; the vehicle nitrogen oxides (NOx) emission trend is divided into two stages: an upward trend between 2006 and 2012 and a downward trend after 2012. Based on a panel threshold, a regression method was used to divide the vehicle NOx and CO emissions in China into four emission zones: low emissions, medium emissions, high emissions, and extra-high emissions. Vehicle HC emissions were divided into three emission zones, which corresponded to low emissions, medium emissions, and high emissions. Overall, vehicle pollution emission efficiency and per capita GDP have a significant inhibitory effect on the three main air pollutants from vehicles (NOx, HC, CO). Both passenger and freight turnover have significant roles in promoting the three air pollutants from vehicles (NOx, HC, CO). Road density and road carrying capacity have a significant role in promoting vehicle HC and CO emissions. Increasing truck proportion inhibits vehicle CO emissions and promotes vehicle NOx emissions. The urbanization rate has a positive effect on vehicle HC and CO emissions. Moreover, there is obvious heterogeneity in different emission zones of the three air pollutants from vehicles (NOx, HC, CO).

A unified empirical modeling approach for particulate matter and NO2 in a coastal city in China

Modeling air pollutants on a fine spatiotemporal scale is necessary for health studies that focus on critical short-term exposure windows. A unified empirical modeling approach is useful for health studies; however, it is unclear whether this approach can be used in a coastal city for air pollutants driven by local emissions and regional meteorological factors. An advanced empirical modeling approach was used to develop exposure models from October 2012 to December 2019, for particulate matter with aerodynamic diameters less than or equal to 2.5 and 10 μm (PM_2.5 and PM₁₀) and nitrogen dioxide (NO₂) in the coastal city of Shanghai, China. Air pollutant concentrations were obtained from daily measurements at 55 administrative monitoring sites that were integrated into three-day average concentrations. Data on a large array of geographic variables were collected, and their dimensions were reduced using the partial least squares regression method. A geostatistical model using the land-use regression approach in a universal kriging framework was developed to estimate short-term exposure concentrations. The prediction ability of the models were determined by leave-one (site)-out cross-validation (LOOCV) and external validation (EV). Compared to the LOOCV results, the EV results for PM_2.5 and PM₁₀ were consistently reliable, but the EV for NO₂ had a larger root mean squared error. The temporal random effects involved in the model structure were interpreted using sensitivity analyses. This affected the short-term PM_2.5 and PM₁₀ model predictions. This unified empirical modeling approach was successfully used for particulate matter in Shanghai, where air pollution is affected by complex regional and meteorological conditions. These exposure models are going to be applied for making exposure predictions at residential locations for short-term exposure predictions in the "Growth trajectories and air pollution" (GAAP) study in Shanghai that focuses on maternal and early life exposure to air pollutants.

A time series analysis of ambient air pollution and low birth weight in Xuzhou, China

The objective of this study was to examine the relationship between weekly specific maternal air pollution exposures and low birth weight. We fitted a distributed lag nonlinear model (DLNM) to analyze the nonlinear exposure-response association and delayed effects of air pollutants on the risk for low birth weight. The model assumed that all live births have 40 gestational weeks.The 1st week lag was the 40th gestational week, and 40th lag week was the 1st gestational week.The study included 71,809 live births (from July 1, 2016, to June 30, 2019), of which 2,391 (3.33%) exhibited low birth weight. The results demonstrated that exposure of pregnant women to PM10 at lag 22-30 weeks was significantly associated with low birth weight risk, with the greatest impact at the lag 30 week. Exposure to SO2 at lag 29-37 weeks was significantly associated with low birth weight risk. The sensitive exposure window for NO2 began at lag 25-37 weeks of pregnancy. The lag 6-10 weeks constituted the susceptible exposure window for O3. Therefore we concluded that maternal exposures to PM10, SO2, NO2, and O3 were associated with increased risk for low birth weight.

Cows as canaries: The effects of ambient air pollution exposure on milk production and somatic cell count in dairy cows

Exposure to air pollution, including criteria pollutants such as fine particulate matter (PM_2.5) and ozone (O₃), has been associated with morbidity and mortality in mammals. As a genetically homogenous population that is closely monitored for health, dairy cattle present a unique opportunity to assess the association between changes in air pollution and mammalian health. Milk yield decreases in the summer if temperature and humidity, measured by the Temperature Humidity Index (THI). As O₃ levels increase with warmer temperatures, and summer PM_2.5 may increase with wildfire smoke, dairy cows may serve as a useful sentinel species to evaluate subacute markers of inflammation and metabolic output and ambient pollution. Over two years, we assessed summertime O₃ and PM_2.5 concentrations from local US EPA air quality monitors into an auto-regressive mixed model of the association between THI and daily milk production data and bulk tank somatic cell count (SCC). In unadjusted models, a 10 unit increase THI was associated with 28,700 cells/mL (95% CI: 17,700, 39,690) increase in SCC. After controlling for ambient air pollutants, THI was associated with a 14,500 SCC increase (95% CI: 3,400, 25,680), a 48% decrease in effect compared to the crude model. Further, in fully adjusted models, PM_2.5 was associated with a 105,500 cells/mL (95% CI: 90,030, 121,050) increase in SCC. Similar results were found for milk production. Results were amplified when high PM_2.5 days (95th percentile of observed values) associated with wildfire smoke were removed from the analyses. Our results support the hypothesis that PM_2.5 confounds the relationships between THI and milk yield and somatic cell count. The results of this study can be used to inform strategies for intervention to mitigate these impacts at the dairy level and potentially contribute to a model where production animals can act as air quality sentinels.

Harmful Effect of Intrauterine Smoke Exposure on Neuronal Control of "Fetal Breathing System" in Stillbirths

This article is aimed to contribute to the current knowledge on the role of toxic substances such as nicotine on sudden intrauterine unexplained deaths’ (SIUDS’) pathogenetic mechanisms. The in-depth histopathological examination of the autonomic nervous system in wide groups of victims of SIUDS (47 cases) and controls (20 cases), with both smoking and no-smoking mothers, highlighted the frequent presence of the hypodevelopment of brainstem structures checking the vital functions. In particular, the hypoplasia of the pontine parafacial nucleus together with hypoplastic lungs for gestational age were observed in SIUDS cases with mothers who smoked cigarettes, including electronic ones. The results allow us to assume that the products of cigarette smoke during pregnancy can easily cross the placental barrier, thus entering the fetal circulation and damaging the most sensitive organs, such as lungs and brain. In a non-negligible percentage of SIUDS, the mothers did not smoke. Furthermore, based on previous and ongoing studies conducted through analytical procedures and the use of scanning electron microscopy, the authors envisage the involvement of toxic nanoparticles (such as agricultural pesticides and nanomaterials increasingly used in biomedicine, bioscience and biotechnology) in the death pathogenesis, with similar mechanisms to those of nicotine.

Safe in the womb? Effects of air pollution to the unborn child and neonates

OBJECTIVE

In this brief review, the authors focus on the effects of gestational exposures to urban air pollution on fetal development and neonatal outcomes.

SOURCE OF DATA

In this review the authors used PubMed, Web of Science and SciELO research platforms, analyzing papers from the last 30 years.

SUMMARY OF THE FINDINGS

Epidemiological and experimental evidence agree that gestational exposure to air pollution in urban increases the risks for low birth weight, preterm birth, congenital malformation, intrauterine growth restriction, and neonatal mortality. Furthermore, exposures are associated with increased risks for preeclampsia, hypertension, gestational diabetes.

CONCLUSIONS

Therefore, it is time for greater involvement and engagement of the health sector in the discussion of public policies that may affect the quality of the environment, and that directly or indirectly impact the health of those who were not yet born.

Critical Time Windows for Air Pollution Exposure and Birth Weight in a Multicity Canadian Pregnancy Cohort

BACKGROUND

Maternal prenatal exposure to air pollution has been associated with adverse birth outcomes. However, previous studies focused on a priori time intervals such as trimesters reported inconsistent associations.

OBJECTIVES

We investigated time-varying vulnerability of birth weight to fine particulate matter (PM2.5) and nitrogen dioxide (NO2) using flexible time intervals.

METHODS

We analyzed 1,300 live, full-term births from Maternal-Infant Research on Environmental Chemicals, a Canadian prospective pregnancy cohort spanning 10 cities (2008-2011). Daily PM2.5 and NO2 concentrations were estimated from ground-level monitoring, satellite models, and land-use regression, and assigned to participants from pre-pregnancy through delivery. We developed a flexible two-stage modeling method-using a Bayesian Metropolis-Hastings algorithm and empirical density threshold-to identify time-dependent vulnerability to air pollution without specifying exposure periods a priori. This approach identified critical windows with varying lengths (2-363 days) and critical windows that fell within, or straddled, predetermined time periods (i.e., trimesters). We adjusted the models for detailed infant and maternal covariates.

RESULTS

Critical windows associated with reduced birth weight were identified during mid- to late-pregnancy for both PM2.5 and NO2: -6 g (95% credible interval: -11, -1 g) and -5 g (-10, -0.1 g) per µg/m3 PM2.5 during gestational days 91-139 and 249-272, respectively; and -3 g (-5, -1 g) per ppb NO2 during days 55-145.

DISCUSSION

We used a novel, flexible selection method to identify critical windows when maternal exposures to air pollution were associated with decrements in birth weight. Our results suggest that air pollution impacts on fetal development may not be adequately captured by trimester-based analyses.

Prenatal exposure to polycyclic aromatic hydrocarbons and effects on neonatal anthropometric indices and thyroid-stimulating hormone in a Middle Eastern population

Prenatal exposure to polycyclic aromatic hydrocarbons (PAHs) evokes extensive concerns regarding public health. Monitoring the pregnant women's exposure can be considered a suitable alternative to assess the fetus's exposure. This study aimed to monitor pregnant women's exposure (n = 126) to PAHs using a biomonitoring approach to evaluate effects on anthropometric indices and neonatal thyroid-stimulating hormone (TSH) in Shiraz, Iran. PAHs priority compounds were measured by gas chromatography-mass spectrometry (GC-MS) after separating blood serum and liquid-liquid extraction (LLE) method. Information on anthropometric indices, neonatal TSH levels, and data from the respondents was obtained from medical records and questionnaires. The mean PAHs concentrations ranged from 0.29 to 327.91 ng/g lipid. There was no significant difference between the measured PAHs in maternal serum at the seventh month and pregnancy termination except for ACY (p-Value<0.05). Regression analysis results showed a significant correlation (p-value<0.05) between exposure to passive smoke and total PAHs concentrations. There was no significant relationship between exposure to PAHs and weight, height, head circumference, and Apgar score of newborns. The results showed TSH decreased by 0.99 units as ACE increased per unit (β = -0.001). This study is the first to evaluate relationships between prenatal exposure to PAHs and effects on newborn health indicators, including TSH levels in a Middle Eastern population. Future studies are suggested to perform detailed assessments of PAHs intake sources, especially in vulnerable populations such as pregnant women and children.

Association Between Ambient Air Pollutants Exposure and Preterm Birth in Women Who Underwent in vitro Fertilization: A Retrospective Cohort Study From Hangzhou, China

Objectives: Exposure to air pollutants has been linked to preterm birth (PTB) after natural conception. However, few studies have explored the effects of air pollution on PTB in patients who underwent in vitro fertilization (IVF). We aimed to investigate the association between ambient air pollutants exposure and PTB risk in IVF patients.

Methods: This retrospective cohort study included 2,195 infertile women who underwent IVF treatment from January 2017 and September 2020 in Hangzhou Women's Hospital. Totally 1,005 subjects who underwent a first fresh embryo(s) transfer cycle were analyzed in this study. Residential exposure to ambient six air pollutants (PM_2.5, PM₁₀, SO₂, NO₂, CO, O₃) during various periods of the IVF timeline were estimated by satellite remote-sensing and ground measurement. Cox proportional hazards models for discrete time were used to explore the association between pollutants exposure and incident PTB, with adjustment for confounders. Stratified analyses were employed to explore the effect modifiers.

Results: The clinical pregnancy and PTB rates were 61.2 and 9.3%, respectively. We found that PM_2.5 exposure was significantly associated with an increased risk of PTB during 85 days before oocyte retrieval [period A, adjusted hazard ratio, HR=1.09, 95%CI: 1.02–1.21], gonadotropin start to oocyte retrieval [period B, 1.07 (1.01–1.19)], first trimester of pregnancy [period F, 1.06 (1.01–1.14)], and the entire IVF pregnancy [period I, 1.07 (1.01–1.14)], respectively. An interquartile range increment in PM₁₀ during periods A and B was significantly associated with PTB at 1.15 (1.04–1.36), 1.12 (1.03–1.28), and 1.14 (1.01–1.32) for NO₂ during period A. The stratified analysis showed that the associations were stronger for women aged <35 years and those who underwent two embryos transferred.

Conclusions: Our study suggests ambient PM_2.5, PM₁₀, and NO₂ exposure were significantly associated with elevated PTB risk in IVF patients, especially at early stages of IVF cycle and during pregnancy.

Dynamics of skin microvascular blood flow in 4-6-year-old children in association with pre- and postnatal black carbon and particulate air pollution exposure

BACKGROUND

A growing body of evidence indicates that cardiovascular health in adulthood, particularly that of the microcirculation, could find its roots during prenatal development. In this study, we investigated the association between pre- and postnatal air pollution exposure on heat-induced skin hyperemia as a dynamic marker of the microvasculature.

METHODS

In 139 children between the ages of 4 and 6 who are followed longitudinally within the ENVIRONAGE birth cohort, we measured skin perfusion by Laser Doppler probes using the Periflux6000. Residential black carbon (BC), particulate (PM₁₀ and PM_2.5) air pollution, and nitrogen dioxide (NO₂) levels were modelled for each participant's home address using a high-resolution spatiotemporal model for multiple time windows. We assessed the association between skin hyperemia and pre- and postnatal air pollution using multiple regression models while adjusting for relevant covariates.

RESULTS

Residential BC exposure during the whole pregnancy averaged (IQR) 1.42 (1.22-1.58) µg/m³, PM₁₀ 18.88 (16.64 - 21.13) µg/m³, PM_2.5 13.67 (11.5 - 15.56) µg/m³ and NO₂ 18.39 (15.52 - 20.31) µg/m³. An IQR increment in BC exposure during the third trimester of pregnancy was associated with an 11.5 % (95% CI: -20.1 to -1.9; p = 0.020) lower skin hyperemia. Similar effect estimates were retrieved for PM₁₀, PM_2.5 and NO₂ (respectively 13.9 % [95% CI: -21.9 to -3.0; p = 0.003], 17.0 % [95% CI: -26.7 to -6.1; p = 0.004] and 12.7% [95 % CI: -22.2 to -1.9; p = 0.023] lower skin hyperemia). In multipollutant models, PM_2.5 showed the strongest inverse association with skin hyperemia. Postnatal exposure to BC, PM₁₀, PM_2.5 or NO₂, was not associated with skin hyperemia at the age of 4 to 6, and did not alter the previous reported prenatal associations when taken into account.

CONCLUSION

Our findings support that BC, particulate air pollution, and NO₂ exposure, even at low concentrations, during prenatal life, can have long-lasting consequences for the microvasculature. This proposes a role of prenatal air pollution exposures over and beyond postnatal exposure in the microvascular alterations which were persistent into childhood.

The Mediating Role of Placental Weight Change in the Association Between Prenatal Exposure to Thallium and Birth Weight: A Prospective Birth Cohort Study

Background: Previous studies have demonstrated the embryotoxicity and fetotoxicity of thallium (Tl). However, the effects of prenatal exposure to Tl on birth weight and placental weight and the mediating role of placental weight in the association of Tl with birth weight remain unclear.

Methods: We recruited 2,748 participants from the ongoing Prenatal Environment and Offspring Health Cohort (PEOH Cohort) study, which was initiated in 2016 in Guangzhou, China. The Tl concentrations in maternal urine samples collected during the first and third trimester were determined by inductively coupled plasma mass spectrometry. Birth weight and placental weight were extracted from maternal medical records.

Results: Pregnant women exposed to the highest tertile of Tl in the first trimester (β = −42.7 g, 95% CI: −82.3, −3.1 g) and third trimester (β = −50.6 g, 95% CI: −99.0, −2.3 g) had babies with lower birth weights than those exposed to the lowest tertile. We also found significant negative associations of exposure to Tl concentrations in the first and third trimester with placental weight. Mediation analyses showed that 50.3% (95% CI: 15.9, 79.2%) and 33.5% (95% CI: 1.3, 80.3%) of the effects of Tl exposure in the first and third trimester on birth weight were mediated by decreased placental weight.

Conclusion: Our results suggest that prenatal exposure to Tl is negatively associated with birth weight and that this association may be mediated by decreased placental weight.

Adverse effects of prenatal exposure to residential dust on post-natal brain development

BACKGROUND

Previous studies have shown an association between prenatal exposure to particulate matter (PM) and adverse brain development. However, it is unclear whether gestational exposure to community-sampled residential PM has an impact on the developing brain.

OBJECTIVES

We aimed to test whether in utero exposure to PM from residential roof spaces (ceiling voids) alters critical foetal neurodevelopmental processes.

METHODS

Pregnant C57BL/6 mice were intranasally exposed to 100 μg of roof space particles (~5 mg kg^-1) in 50 μl of saline, or saline alone under light methoxyflurane anaesthesia, throughout mid-to-late gestation. At 2 weeks post-natal age, pups were sacrificed and assessed for body and brain growth. The brain tissue was collected and examined for a range of neurodevelopmental markers for synaptogenesis, synaptic plasticity, gliogenic events and myelination by immunohistochemistry.

RESULTS

Gestational exposure to roof space PM reduced post-natal body and brain weights. There was no significant effect of roof space PM exposure on synaptogenesis, synaptic plasticity or astrocyte density. However, PM exposure caused increased myelin load in the white matter and elevated microglial density which was dependent on the PM sample. These effects were found to be consistent between male and female mice.

CONCLUSIONS

Our data suggest that exposure to residential roof space PM during pregnancy impairs somatic growth and causes neuropathological changes in the developing brain.

Inflammasome Activation in Pollution-Induced Skin Conditions

SUMMARY

Exposure to air pollutants has been now associated with detrimental effects on a variety of organs, including the heart, lungs, GI tract, and brain. However, recently it has become clear that pollutant exposure can also promote the development/exacerbation of a variety of skin conditions, including premature aging, psoriasis, acne, and atopic dermatitis. Although the molecular mechanisms by which pollutant exposure results in these cutaneous pathological manifestations, it has been noticed that an inflammatory status is a common denominator of all those skin conditions. For this reason, recently, the activation of a cytosolic multiprotein complex involved in inflammatory responses (the inflammasome) that could promote the maturation of proinflammatory cytokines interleukin-1β and interleukin-18 has been hypothesized to play a key role in pollution-induced skin damage. In this review, we summarize and propose the cutaneous inflammasome as a novel target of pollutant exposure and the eventual usage of inflammasome inhibitor as new technologies to counteract pollution-induced skin damage. Possibly, the ability to inhibit the inflammasome activation could prevent cutaneous inflammaging and ameliorate the health and appearance of the skin.

Prenatal particulate matter exposure and Intrauterine Fetal Death

BACKGROUND

Intrauterine Fetal Death (IUFD) is a rare and tragic pregnancy complication. The main causes for IUFD are largely unknown. Particulate Matter (PM)2.5 exposure has been suggested as an IUFD risk factor.

OBJECTIVES

To study the association between maternal PM2.5 levels and IUFD risk, to address ethnicity as a possible effect modifier, and to identify a prenatal period during which PM2.5 is most harmful regarding IUFD risk.

METHODS

This is a retrospective cohort study, which included pregnant women at the Soroka University Medical Center between the years 2003-2017. Estimated PM2.5 levels were calculated per residence, using a hybrid model incorporating daily satellite remote sensing data at a 1 km spatial resolution. Multiple gestations, fetuses with congenital malformations or chromosomal abnormalities were excluded. Mean PM2.5 level was calculated per trimester, the entire pregnancy and the last gestational week. Analyses were also performed separately for the two ethnic groups in the study: Jews and Bedouin-Arabs. Multivariable analysis were applied to study the association between PM2.5 exposure at the different periods and IUFD risk.

RESULTS

The study included 87,887 pregnancies, 444 (0.5%) ended with IUFD. Mean PM2.5 levels ranged between 18.18 and 22.32 μm. First trimester and entire pregnancy PM2.5 levels were significantly associated with increased IUFD risk among Jewish women only. In a multivariable model, for every 10 μg/m³ unit increase in PM2.5 the risk for IUFD increases by 2.98 (95%CI 1.50-5.90) and by 3.61 (95%CI 1.32-9.85) during first trimester and the entire pregnancy, respectively, while adjusting for maternal age, smoking, socioeconomic score and season.

CONCLUSIONS

In this retrospective cohort an association was found between PM2.5 levels and IUFD among Jewish women only. These results strengthen the importance of addressing this effect modifier when studying air pollution effects on human health.

Household Air Pollution from Biomass Fuel for Cooking and Adverse Fetal Growth Outcomes in Rural Sri Lanka

The aim of this study was to investigate the impact of biomass fuel for cooking on adverse fetal growth outcomes in Sri Lanka. A cross-sectional study of mothers recruited at maternity clinics in rural communities in Sri Lanka’s Central Province was undertaken. Data pertaining to household air pollution and fetal growth parameters were collected using an interviewer-administered questionnaire. Logistic regression models, adjusted for potential confounders, were used to evaluate the impact of biomass fuel for cooking on low birth weight (LBW) and small for gestational age (SGA) parameters. Findings showed that exposure to biomass cooking fuels during pregnancy was associated with an increased risk of LBW adjusted odds ratio (aOR) 2.74 (95% CI 1.08–6.96) and SGA (aOR: 1.87, 95% CI 1.03–3.41) compared with the use of clean energy. The risk of LBW was highest for traditional biomass stoves compared to improved biomass stoves (aOR: 3.23, 95% 1.17–8.89) and biomass use in kitchens without a chimney compared to kitchens with a chimney (aOR: 4.63, 95% 1.54–13.93). Similar trends were observed for SGA.

Prenatal exposure to fine particulate matter and fetal growth: a cohort study from a velocity perspective

BACKGROUND

Reduced growth velocity before birth increases the risk of adverse health outcomes in adult life. However, until recently, there has been a lack of studies demonstrating the impact of prenatal PM_2.5 exposure on fetal growth velocity.

METHODS

The current study was embedded in a previous cohort built between January 1, 2014, and April 30, 2015, in Shanghai First Maternity and Infant Hospital, China, in 6129 eligible singleton pregnancies. The PM_2.5 concentration was estimated by an inverse distance weighted method according to the residential addresses of the participants. Repeated fetal biometry measurements, including head circumference (HC), abdominal circumference (AC), femur length (FL), and biparietal diameter (BPD), were measured through ultrasound between 14 and 41 gestational weeks. A principal component analysis through conditional expectation for sparse longitudinal data was used to estimate the corresponding velocities.

RESULTS

A total of 22782 ultrasound measurements were conducted among 6129 participants with a median of 2 and a maximum of 9 measurements. With each 10 μg/m³ increase in cumulative PM_2.5 exposure, the velocity of HC, AC FL and BPD decreased by 0.12 mm/week, 0.17 mm/week, 0.02 mm/week and 0.02 mm/week, respectively, on average. The results of the Generalized Functional Concurrent Model showed that the velocity decreased significantly with PM_2.5 exposure between 22 and 32 gestational weeks, which might be the potential sensitive exposure window.

CONCLUSIONS

There are negative associations between prenatal exposure to PM_2.5 and fetal growth velocity, and the late second trimester and early third trimester might be the potential sensitive window.

Impact of air pollution exposure during various periods of pregnancy on term birth weight: a large-sample, retrospective population-based cohort study

Previous studies have suggested that maternal exposure to air pollution might affect term birth weight. However, the conclusions are controversial. Birth data of all term newborns born in Xi'an city of Shaanxi, China, from 2015 to 2018 and whose mother lived in Xi'an during pregnancy were selected form the Birth Registry Database. And the daily air quality data of Xi'an city was collected from Chinese Air Quality Online Monitoring and Analysis Platform. Generalized additive models (GAM) and 2-level binary logistic regression models were used to estimate the effects of air pollution exposure on term birth weight, the risk term low birth weight (TLBW), and macrosomia. Finally, 321521 term newborns were selected, including 4369(1.36%) TLBW infants and 24,960 (7.76%) macrosomia. The average pollution levels of PM2.5, PM10, and NO2 in Xi'an city from 2015 to 2018 were higher than national limits. During the whole pregnancy, maternal exposure to PM2.5, PM10, SO2, and CO all significantly reduced the term birth weight and increased the risk of TLBW. However, NO2 and O3 exposure have significantly increased the term birth weight, and O3 even increased the risk of macrosomia significantly. Those effects were also observed in the first and second trimesters of pregnancy. But during the third trimester, high level of air quality index (AQI) and maternal exposure to PM2.5, PM10, SO2, NO2, and CO increased the term birth weight and the risk of macrosomia, while O3 exposure was contrary to this effect. The findings suggested that prenatal exposure to air pollution might cause adverse impacts on term birth weight, and the effects varied with trimesters and pollutants, which provides further pieces of evidence for the adverse effects of air pollution exposure in heavy polluted-area on term birth weight.

Household air pollution and under-five mortality in sub-Saharan Africa: an analysis of 14 demographic and health surveys

BACKGROUND

Globally, over four million deaths are attributed to exposure to household air pollution (HAP) annually. Evidence of the association between exposure to HAP and under-five mortality in sub-Saharan Africa (SSA) is insufficient. We assessed the association between exposure to HAP and under-five mortality risk in 14 SSA countries.

METHODS

We pooled Demographic and Health Survey (DHS) data from 14 SSA countries (N = 164376) collected between 2015 and 2018. We defined exposure to HAP as the use of biomass fuel for cooking in the household. Under-five mortality was defined as deaths before age five. Data were analyzed using mixed effects logistic regression models.

RESULTS

Of the study population, 73% were exposed to HAP and under-five mortality was observed in 5%. HAP exposure was associated with under-five mortality, adjusted odds ratio (OR) 1.33 (95% confidence interval (CI) [1.03-1.71]). Children from households who cooked inside the home had higher risk of under-five mortality compared to households that cooked in separate buildings [0.85 (0.73-0.98)] or outside [0.75 (0.64-0.87)]. Lower risk of under-five mortality was also observed in breastfed children [0.09 (0.05-0.18)] compared to non-breastfed children.

CONCLUSIONS

HAP exposure may be associated with an increased risk of under-five mortality in sub-Saharan Africa. More carefully designed longitudinal studies are required to contribute to these findings. In addition, awareness campaigns on the effects of HAP exposure and interventions to reduce the use of biomass fuels are required in SSA.

Maternal exposure to air pollution and the risk of low birth weight: A meta-analysis of cohort studies

Previous studies have evaluated the relationship between prenatal air pollution exposure and low birth weight, but the results are inconsistent. The purpose of this meta-analysis is to quantitatively analyze the relationship between maternal air pollutant exposure and low birth weight (LBW). PubMed and Web of Science databases were searched to obtain the studies on the relationship between the prenatal exposure of air pollutants and LBW that published as of June 2020. The pooled effects of air pollutant exposure and LBW were calculated using random-effect model (for studies with significant heterogeneity) or fixed-effect model (for studies without significant heterogeneity). Totally, 54 studies were included in this meta-analysis. The pooled effect of PM_2.5, PM₁₀, NO₂, CO, SO₂, and O₃ exposure on LBW were 1.081 (95% CI: 1.043, 1.120), 1.053 (95% CI: 1.030, 1.076), 1.030 (95% CI: 1.008, 1.053), 1.007 (95% CI: 1.001, 1.014), 1.125 (95% CI: 1.017, 1.244), and 1.045 (95% CI: 1.005, 1.086), respectively. NO₂ (per 10 ppb increase) and CO (per 100 ppb increase) exposure in the first trimester were positively correlated with LBW, of which the pooled effect was 1.022 (95% CI: 1.009, 1. 035) and 1.008 (95% CI: 1.004, 1.012), respectively. PM_2.5 (per 10 μg/m³ increase) exposure in the third trimester significantly affected the LBW, of which the pooled effect was 1.053 (95% CI: 1.010, 1.097). In addition, PM₁₀ (per 10 μg/m³ increase) exposure in the second trimester also significantly affected the LBW, with the pooled effect of 1.011 (95% CI: 1.005, 1.017). Prenatal exposure of the major air pollutants during the entire pregnancy could increase the risk of LBW, while the susceptible window of the pollutants varied.

The effect of exposure to particulate matter during pregnancy on lower respiratory tract infection hospitalizations during first year of life

BACKGROUND

Lower respiratory tract infections (LRTI) in early life, including pneumonia, bronchitis and bronchiolitis, can lead to decreased lung function, persistent lung damage and increased susceptibility to various respiratory diseases such as asthma. In-utero exposure to particulate matter (PM) during pregnancy may disrupt biological mechanisms that regulate fetal growth, maturation and development. We aimed to estimate the association between intrauterine exposure to PM of size < 2.5 μm in diameter (PM_2.5) and incidence of LRTIs during the first year of life.

METHODS

A retrospective population-based cohort study in a population of mothers and infants born in Soroka University Medical Center (SUMC) in the years 2004-2012. All infants < 1 year old that were hospitalized due to LRTIs were included. The main exposure assessment was based on a hybrid model incorporating daily satellite-based predictions at 1 km² spatial resolution. Data from monitoring stations was used for imputation of main exposure and other pollutants. Levels of environmental exposures were assigned to subjects based on their residential addresses and averaged for each trimester. Analysis was conducted by a multivariable generalized estimating equation (GEE) Poisson regression. Data was analyzed separately for the two main ethnic groups in the region, Jewish and Arab-Bedouin.

RESULTS

The study cohort included 57,331 deliveries that met the inclusion criteria. Overall, 1871 hospitalizations of infants < 1 year old due to pneumonia or bronchiolitis were documented. In a multivariable analysis, intrauterine exposure to high levels of PM_2.5 (> 24 μg/m³) in the first and second trimesters was found to be adversely associated with LRTIs in the Arab-Bedouin population (1st trimester, RR = 1.31, CI 95% 1.08-1.60; 2nd trimester: RR = 1.34, CI 95% 1.09-1.66).

CONCLUSION

Intrauterine exposure to high levels of PM_2.5 is associated with a higher risk of hospitalizations due to lower respiratory tract infections in Arab-Bedouin infants.

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.

Temporal and spatial analysis of traffic - Related pollutant under the influence of the seasonality and meteorological variables over an urban city in Peru

A four yearlong air monitoring data (since 2015 to 2018) was collected to assess the impact of meteorological parameters such as temperature, relative humidity, wind speed and wind direction on the spatial and temporal variability of CO (carbon monoxide), NO₂ (nitrogen oxide), O₃ (ozone), SO₂ (sulfur dioxide), PM₁₀ and PM_2.5 (particulate matter with diameter aerodynamic less than 2.5 μm and 10 μm respectively) in Lima Metropolitan Area (LMA). Data from eight air quality monitoring stations, currently under the supervision of the National Meteorological and Hydrological Service (SENAMHI), was used to capture traffic – related pollutants concentrations under various local traffic conditions. Effects on meteorological events on seasonal traffic-related pollutants concentration variability were identified. Using average data from the eight stations, it was found that the monthly mean traffic-related pollutants since 2015 to 2018 were higher in spring and winter and lower in autumn and summer. Low-wind speed was associated with events that contribute to elevated seasonal PM_2.5 levels. Correlation coefficients between PM_2.5 concentrations and meteorological variables fluctuated significaly across different seasons. High PM_2.5 concentrations were associated with low relative humidity and high wind conditions in spring. Results suggest that there exist a seasonal variation of PM_2.5 concentration, and set the need of future work on the understanding of the air pollution effects on human health.

A Systematic Review and Meta-Analysis of Associations between Green and Blue Spaces and Birth Outcomes

Previous studies suggest that green and blue spaces may promote several health outcomes including birth outcomes. However, no synthesis of previous work has specifically asked policy-relevant questions of how much and what type is needed in every neighborhood to elicit these benefits at the population level. A systematic review and meta-analyses were conducted to synthesize thirty-seven studies on the association between residential green and blue spaces and pregnancy outcomes. Meta-analyses were performed for birth weight (BW), small for gestational age (SGA), low birth weight (LBW) and preterm birth (PTB). Increase in residential greenness was statistically significantly associated with higher BW [β = 0.001, 95%CI: (<0.001, 0.002)] and lower odds of SGA [OR = 0.95, 95%CI: (0.92, 0.97)]. Associations between green space and LBW and PTB were as hypothesized but not statistically significant. Associations between blue spaces and pregnancy outcomes were not evident. No study explicitly examined questions of threshold, though some evidence of nonlinearity indicated that moderate amounts of green space may support more favorable pregnancy outcomes. Policy-relevant green and blue space exposures involving theory-driven thresholds warrant testing to ensure future investments in urban greening promote healthier pregnancy outcomes.

Effects of particulate matter exposure on semen quality: A retrospective cohort study

BACKGROUND

Particulate matter (PM) exposure is closely associated with male infertility. Even though an association between poor semen quality and PM exposure has been widely accepted, which and when the semen parameter could be affected are still controversial. The purpose of this study is to estimate the effects of PM exposure on semen quality in Huai'an, China.

OBJECTIVES AND METHODS

The study included 1955 men with 2073 semen samples between 2015 and 2017 with moderate to high exposure to air pollution in Huai'an, China. Three multivariable linear regression models were used to conduct exposure-response analyses for PM exposure and semen quality and to estimate the influence during different exposure periods by every 15 days period before ejaculation in all participants group and normal semen quality participants group.

RESULTS

The average age of the observations was 28.9 ± 5.4 old years and the average abstinence period was 4.2 ± 1.5 days. The results showed high correlations between both PM2.5 and PM10 exposures throughout entire spermatogenesis and the declines of sperm count (β: -0.93, p < 2 × 10-16 and β: -1.00, p < 2 × 10-16), and sperm concentration (β: -1.00, p < 2 × 10-16 and β: -1.06, p < 2 × 10-16), and PM10 exposure decreased sperm total motility (β: -0.60, p = 2.56 × 10-7), but not sperm progressive motility. Furthermore, PM2.5 exposure decreased sperm count and concentration during 15-75 lag days, and PM10 exposure showed significant association with sperm count and concentration during 0-75 lag days. PM2.5 and PM10 exposures during 45-59 lag days were both inversely associated with sperm total motility (all p value < 0.05).

CONCLUSION

The present study revealed that ambient PM exposure throughout spermatogenesis during a long period, especially at early and middle stage were adversely associated with semen quality, sperm count and sperm concentration in particular.

Urban-level environmental factors related to pediatric asthma

During the 20th century, urbanization has increasing and represented a major demographic and environmental change in developed countries. This ever-changing urban environment has an impact on disease patterns and prevalence, namely on noncommunicable diseases, such as asthma and allergy, and poses many challenges to understand the relationship between the changing urban environment and the children health. The complex interaction between human beings and urbanization is dependent not only on individual determinants such as sex, age, social or economic resources, and lifestyles and behaviors, but also on environment, including air pollution, indoors and outdoors, land use, biodiversity, and handiness of green areas. Therefore, the assessment and identification of the impact of urban environment on children's health have become a priority and many recent studies have been conducted with the goal of better understanding the impacts related to urbanization, characterizing indoor air exposure, identifying types of neighborhoods, or characteristics of neighborhoods that promote health benefits. Thus, this review focuses on the role of urban environmental factors on pediatric asthma.

Quantifying and spatial disaggregation of air pollution emissions from ground transportation in a developing country context: Case study for the Lima Metropolitan Area in Peru

Ambient air pollution contributes approximately 3.7 million premature deaths annually worldwide with air pollution from ground transportation posing a significant threat in urban areas. This concern is especially relevant in cities with fast-growing economies in the developing countries, as is the case of Lima Metropolitan Area (LMA) in Peru. Currently, there is a limited understanding of the impacts of ground transportation emissions on air pollution and population health in the LMA. In this study we quantified air pollution emissions from ground transportation, by combining local transportation and meteorological data with emission factors determined by the United States Environmental Protection Agency's (US-EPA's) Motor Vehicle Emission Simulator (MOVES). Total annual emissions of carbon monoxide, nitrogen oxides, sulfur dioxide and particulate matter (PM_2.5) were quantified, temporally resolved and then spatially disaggregated within the LMA study domain. Our study, therefore, provides an approach for quantifying transportation emissions for a large metropolitan area in a developing country where detailed data is not available. This research sets the need of future work aiming at understanding the impact of ground transportation emissions, air pollution levels and their subsequent effects on human health. CAPSULE: We provide a framework for computing and spatially disaggregating air pollution emissions from ground transportation in a rapidly growing economy in a developing country context.

Effects of prenatal exposure to air particulate matter on the risk of preterm birth and roles of maternal and cord blood LINE-1 methylation: A birth cohort study in Guangzhou, China

BACKGROUND

Epidemiological studies have found that increased risk of preterm birth (PTB) is associated with higher prenatal exposure to PM₁₀ and PM_2.5, but few studies have been conducted to assess the impacts of extremely fine particulate matter (PM₁) which may have more toxic effects than other types of ambient particulate air pollution (PM). Several studies have separately investigated the associations between DNA methylation and PTB risk and PM. Maternal LINE-1 methylation level negatively correlated with prenatal exposure to PM and risk of PTB. A comprehensive picture is lacking regarding the associations between prenatal exposure to PM, LINE-1 methylation, and risk of PTB.

OBJECTIVES

This study aimed to estimate the effects of exposure to ambient PM (PM₁₀, PM_2.5, and PM₁) of different sizes during pregnancy on risk of PTB, identify susceptible exposure windows, and illustrate the roles of LINE-1 methylation in the associations between PM and PTB risk.

METHODS

The Birth Cohort Study on Prenatal Environments and Offspring Health (PEOH) has been ongoing since 2016 in Guangzhou, China. A total of 4928 pregnant women were recruited during early pregnancy, and 4278 (86.8%) were successfully followed-up. Each individual weekly exposure to PM₁₀ and PM_2.5 from 3 months before pregnancy to childbirth was assessed using a spatiotemporal land use regression model, and the weekly PM₁ exposure was estimated by employing a generalized additive model. Maternal and cord blood LINE-1 methylation levels (%5mC) were tested using bisulfite-PCR pyrosequencing. A distributed lag nonlinear model incorporated with a Cox proportional hazard model was applied to assess the effect of weekly-specific maternal PM exposure on PTB risk, and a multiple-linear regression model was employed to investigate the associations between PM exposure and LINE-1 methylation levels of maternal and cord bloods. We also assessed the associations between LINE-1 methylation levels and PTB risk by using a logistic regression model.

RESULTS

The risk of PTB was positively associated with PM_2.5 and PM₁ concentrations during the 12th to 20th gestational weeks, and the strongest association was in the fourth quartile (Q₄) versus the first quartile (Q₁) and observed during the 16th gestational week (PM_2.5: harzard ratio [HR] = 1.18, 95%CI: 1.04-1.35, IQR = 11.94 μg/m³. PM₁: HR = 1.20, 95%CI: 1.03-1.39, IQR = 11.36 μg/m³). We observed significantly negative associations of PM₁₀(β = -0.51%5mC per 10 μg/m³, P = 0.014), PM_2.5 (β = -0.66%5mC per 10 μg/m³, P = 0.032) and PM₁ (β = -0.67%5mC per 10 μg/m³, P = 0.032) concentrations with cord blood LINE-1 methylation levels, and a negative association between PM₁ concentration and maternal LINE-1 methylation level (β = -0.86%5mC per 10 μg/m³, P = 0.034).

CONCLUSION

Higher prenatal exposure to PM₁ and PM_2.5 during the 12th to 20th gestational weeks was associated with increased risk of PTB. Maternal and fetal LINE-1 methylation alternation might be an underlying mechanism of PM that increasing the risk of PTB.

Associations between PM2.5 and risk of preterm birth among liveborn infants

PURPOSE

Studies suggest exposure to ambient particulate matter less than 2.5 μg/m3 in aerodynamic diameter (PM2.5) may be associated with preterm birth (PTB), but few have evaluated how this is modified by ambient temperature. We investigated the relationship between PM2.5 exposure during pregnancy and PTB in infants without birth defects (1999-2006) and enrolled in the National Birth Defects Prevention Study and how it is modified by concurrent temperature.

METHODS

PTB was defined as spontaneous or iatrogenic delivery before 37 weeks. Exposure was assigned using inverse distance weighting with up to four monitors within 50 kilometers of maternal residence. To account for state-level variations, a Bayesian two-level hierarchal model was developed.

RESULTS

PTB was associated with PM2.5 during the third and fourth months of pregnancy (range: (odds ratio (95% confidence interval) = 1.00 (0.35, 2.15) to 1.49 (0.82, 2.68) and 1.31 (0.56, 2.91) to 1.62 (0.7, 3.32), respectively); no week of exposure conveyed greater risk. Temperature may modify this relationship; higher local average temperatures during pregnancy yielded stronger positive relationships between PM2.5 and PTB compared to nonstratified results.

CONCLUSIONS

Results add to literature on associations between PM2.5 and PTB, underscoring the importance of considering co-exposures when estimating effects of PM2.5 exposure during pregnancy.

Prenatal and postnatal exposure to air pollution and emotional and aggressive symptoms in children from 8 European birth cohorts

BACKGROUND

The association between air pollution exposure and emotional and behavioural problems in children is unclear. We aimed to assess prenatal and postnatal exposure to several air pollutants and child's depressive and anxiety symptoms, and aggressive symptoms in children of 7-11 years.

METHODS

We analysed data of 13182 children from 8 European population-based birth cohorts. Concentrations of nitrogen dioxide (NO₂), nitrogen oxides (NO_x), particulate matter (PM) with diameters of ≤10 μm (PM₁₀), ≤ 2.5 μm (PM_2.5), and between 10 and 2.5 μm (PM_coarse), the absorbance of PM_2.5 filters (PM_2.5abs), and polycyclic aromatic hydrocarbons (PAHs) were estimated at residential addresses of each participant. Depressive and anxiety symptoms and aggressive symptoms were assessed at 7-11 years of age using parent reported tests. Children were classified in borderline/clinical range or clinical range using validated cut offs. Region specific models were adjusted for various socio-economic and lifestyle characteristics and then combined using random effect meta-analysis. Multiple imputation and inverse probability weighting methods were applied to correct for potential attrition bias.

RESULTS

A total of 1896 (14.4%) children were classified as having depressive and anxiety symptoms in the borderline/clinical range, and 1778 (13.4%) as having aggressive symptoms in the borderline/clinical range. Overall, 1108 (8.4%) and 870 (6.6%) children were classified as having depressive and anxiety symptoms, and aggressive symptoms in the clinical range, respectively. Prenatal exposure to air pollution was not associated with depressive and anxiety symptoms in the borderline/clinical range (e.g. OR 1.02 [95%CI 0.95 to 1.10] per 10 μg/m³ higher NO₂) nor with aggressive symptoms in the borderline/clinical range (e.g. OR 1.04 [95%CI 0.96 to 1.12] per 10 μg/m³ higher NO₂). Similar results were observed for the symptoms in the clinical range, and for postnatal exposures to air pollution.

CONCLUSIONS

Overall, our results suggest that prenatal and postnatal exposure to air pollution is not associated with depressive and anxiety symptoms or aggressive symptoms in children of 7 to 11 years old.

Associations between ambient air pollution and mortality from all causes, pneumonia, and congenital heart diseases among children aged under 5 years in Beijing, China: A population-based time series study

BACKGROUND

Previous studies have mainly focused on the associations between particulate matters and infant mortality. However, evidence regarding the associations between gaseous pollutants and mortality among children aged <5 years remains sparse.

OBJECTIVES

The aim of this study was to investigate the associations between ambient air pollution and death among children aged <5 years in Beijing, China, and explore the impact of age, gender and specific causes of death on these associations.

METHODS

Concentrations of ambient air pollution and the number of deaths among children aged <5 years in Beijing from January 2014 to September 2016 were extracted from authoritative electronic databases. The associations were estimated for a single-month lag from the current month up to the previous 5 months (lag0-lag5) and moving averages of the current and previous months (lag01-lag05) using generalized additive Poisson regression (adjusted for time trends, season, meteorological variables and holidays). Subgroup analyses related to age, gender and specific diseases were performed. Two-pollutant models were used to evaluate the possible role of single pollutants.

RESULTS

Sulfur dioxide (SO₂), nitrogen dioxide (NO₂) and carbon monoxide (CO) demonstrated the strongest associations with death among children aged <5 years at lag0, and the estimates decreased or even turned negative with the increasing lag periods. For an interquartile range increase in SO₂, NO₂ and CO at lag0, the odds ratios (OR) were 1.332 (95% CI 1.152-1.539), 1.383 (95% CI 1.113-1.718) and 1.273 (95% CI 1.028-1.575). However, CO lost significance after adjusting for SO₂ and NO₂, and PM_2.5 gained significance (OR 1.548, 95% CI 1.061-2.258) after adjusting for PM₁₀. The ORs for SO₂ and NO₂ remained the most stable across all two-pollutant models. The associations for children aged 1-5 years were stronger than those reported for infants at lag0 but lower at the other lag months. The pollutant associations were stronger for congenital heart disease-related death than overall and pneumonia-related death. We did not find significant differences in terms of gender.

CONCLUSION

Exposure to air pollution may increase the incidence of death among children aged <5 years. SO₂ and NO₂ may be the most stable pollutants reflecting associations between air pollution and death, deserving further attention. Children with congenital heart diseases are more susceptible to air pollution. Therefore, it is urgent to implement the clean air targets established by WHO and reduce the exposure of children to air pollution.

Exposure of trophoblast cells to fine particulate matter air pollution leads to growth inhibition, inflammation and ER stress

Ambient air pollution is considered a major environmental health threat to pregnant women. Our previous work has shown an association between exposure to airborne particulate matter (PM) and an increased risk of developing pre-eclamspia. It is now recognized that many pregnancy complications are due to underlying placental dysfunction, and this tissue plays a pivotal role in pre-eclamspia. Recent studies have shown that PM can enter the circulation and reach the human placenta but the effects of PM on human placental function are still largely unknown. In this work we investigated the effects of airborne PM on trophoblast cells. Human, first trimester trophoblast cells (HTR-8/SV) were exposed to urban pollution particles (Malmö PM2.5; Prague PM10) for up to seven days in vitro and were analysed for uptake, levels of hCGβ and IL-6 secretion and proteomic analysis. HTR-8/SVneo cells rapidly endocytose PM within 30 min of exposure and particles accumulate in the cell in perinuclear vesicles. High doses of Prague and Malmö PM (500-5000 ng/ml) significantly decreased hCGβ secretion and increased IL-6 secretion after 48 h exposure. Exposure to PM (50 ng/ml) for 48h or seven days led to reduced cellular growth and altered protein expression. The differentially expressed proteins are involved in networks that regulate cellular processes such as inflammation, endoplasmic reticulum stress, cellular survival and molecular transport pathways. Our studies suggest that trophoblast cells exposed to low levels of urban PM respond with reduced growth, oxidative stress, inflammation and endoplasmic reticulum stress after taking up the particles by endocytosis. Many of the dysfunctional cellular processes ascribed to the differentially expressed proteins in this study, are similar to those described in PE, suggesting that low levels of urban PM may disrupt cellular processes in trophoblast cells. Many of the differentially expressed proteins identified in this study are involved in inflammation and may be potential biomarkers for PE.

The Modifying Role of Socioeconomic Position and Greenness on the Short-Term Effect of Heat and Air Pollution on Preterm Births in Rome, 2001-2013

Urban green spaces have been associated with health benefits, but few studies have evaluated the role of greenness on pregnancy outcomes. We examined how the association between short-term exposure to heat and air pollution on the probability of preterm delivery is affected by the spatial variation of socioeconomic position (SEP) and greenness. We analyzed a cohort of newborns in Rome, from April to October of 2001-2013, defining preterm as births between the 22nd and the 36th week of gestation. We used a time series approach, with maximum apparent temperature (MAT), PM10, NO2, and O3 as exposure variables. As greenness indicators, we considered maternal residential proximity to green spaces and the Normalized Difference Vegetation Index (NDVI) within a 100 m buffer around each woman's residential address. We enrolled 56,576 newborns (5.1% preterm). The effect of a 1 °C increase in temperature on the daily number of preterm births was higher in women with low SEP (+2.49% (90% CI: 1.29-3.71)) and among those living within 100 m from green spaces (+3.33% (90% CI: 1.82-4.87)). No effect modification was observed for NDVI or PM10. SEP was an important effect modifier of the heat-preterm birth relationship. The role of greenness in modifying this association between heat and preterm delivery should be further investigated.