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

Air pollution and children's mental health in rural areas: compositional spatio-temporal model

Air pollution stands as an environmental risk to child mental health, with proven relationships hitherto observed only in urban areas. Understanding the impact of pollution in rural settings is equally crucial. The novelty of this article lies in the study of the relationship between air pollution and behavioural and developmental disorders, attention deficit hyperactivity disorder (ADHD), anxiety, and eating disorders in children below 15 living in a rural area. The methodology combines spatio-temporal models, Bayesian inference and Compositional Data (CoDa), that make it possible to study areas with few pollution monitoring stations. Exposure to nitrogen dioxide (NO2), ozone (O3), and sulphur dioxide (SO2) is related to behavioural and development disorders, anxiety is related to particulate matter (PM10), O3 and SO2, and overall pollution is associated to ADHD and eating disorders. To sum up, like their urban counterparts, rural children are also subject to mental health risks related to air pollution, and the combination of spatio-temporal models, Bayesian inference and CoDa make it possible to relate mental health problems to pollutant concentrations in rural settings with few monitoring stations. Certain limitations persist related to misclassification of exposure to air pollutants and to the covariables available in the data sources used.

Associations of air pollution exposures in preconception and pregnancy with birth outcomes and infant neurocognitive development: analysis of the Complex Lipids in Mothers and Babies (CLIMB) prospective cohort in Chongqing, China

OBJECTIVES

To investigate the associations of traffic-related air pollution exposures in early pregnancy with birth outcomes and infant neurocognitive development.

DESIGN

Cohort study.

SETTING

Eligible women attended six visits in the maternity clinics of two centres, the First Affiliated Hospital of Chongqing Medical University and Chongqing Health Centre for Women and Children.

PARTICIPANTS

Women who were between 20 and 40 years of age and were at 11-14 weeks gestation with a singleton pregnancy were eligible for participation. Women were excluded if they had a history of premature delivery before 32 weeks of gestation, maternal milk allergy or aversion or severe lactose intolerance. 1273 pregnant women enrolled in 2015-2016 and 1174 live births were included in this analysis.

EXPOSURES

Air pollution concentrations at their home addresses, including particulate matter with diameter ≤2.5 µm (PM2.5) and nitrogen dioxide (NO2), during pre-conception and each trimester period were estimated using land-use regression models.

OUTCOME MEASURES

Birth outcomes (ie, birth weight, birth length, preterm birth, low birth weight, large for gestational age and small for gestational age (SGA) status) and neurodevelopment outcomes measured by the Chinese version of Bayley Scales of Infant Development.

RESULTS

An association between SGA and per-IQR increases in NO2 was found in the first trimester (OR: 1.57, 95% CI: 1.06 to 2.32) and during the whole pregnancy (OR: 1.33, 99% CI: 1.01 to 1.75). Both PM2.5 and NO2 exposure in the 90 days prior to conception were associated with lower Psychomotor Development Index scores (β: -6.15, 95% CI: -8.84 to -3.46; β: -2.83, 95% CI: -4.27 to -1.39, respectively). Increased NO2 exposure was associated with an increased risk of psychomotor development delay during different trimesters of pregnancy.

CONCLUSIONS

Increased exposures to NO2 during pregnancy were associated with increased risks of SGA and psychomotor development delay, while increased exposures to both PM2.5 and NO2 pre-conception were associated with adverse psychomotor development outcomes at 12 months of age.

TRIAL REGISTRATION NUMBER

ChiCTR-IOR-16007700.

Pre-pregnancy ozone and ultrafine particulate matter exposure during second year of life associated with decreased cognitive and adaptive functioning at aged 2-5 years

BACKGROUND

This study sought to investigate the association of prenatal and early life exposure to a mixture of air pollutants on cognitive and adaptive outcomes separately in children with or without autism spectrum disorder (ASD).

METHODS

Utilizing data from the CHARGE case-control study (birth years: 2000-2016), we predicted daily air concentrations of NO2, O3, and particulate matter <0.1 μm (PM0.1), between 0.1 and 2.5 μm (PM0.1-2.5), and between 2.5 and 10 μm (PM2.5-10) using chemical transport models with ground-based monitor adjustments. Exposures were evaluated for pre-pregnancy, each trimester, and the first two years of life. Individual and combined effects of pollutants were assessed with Vineland Adaptive Behavior Scales (VABS) and Mullen Scales of Early Learning (MSEL), separately for children with ASD (n = 660) and children without ASD (typically developing (TD) and developmentally delayed (DD) combined; n = 753) using hierarchical Bayesian Kernel Machine Regression (BKMR) models with three groups: PM size fractions (PM0.1, PM0.1-2.5, PM2.5-10), NO2, and O3.

RESULTS

Pre-pregnancy Ozone was strongly negatively associated with all scores in the non-ASD group (group posterior inclusion probability (gPIP) = 0.83-1.00). The PM group during year 2 was also strongly negatively associated with all scores in the non-ASD group (gPIP = 0.59-0.93), with PM0.1 driving the group association (conditional PIP (cPIP) = 0.73-0.96). Weaker and less consistent associations were observed between PM0.1-2.5 during pre-pregnancy and ozone during year 1 and VABS scores in the ASD group.

CONCLUSIONS

These findings prompt further investigation into ozone and ultrafine PM as potential environmental risk factors for neurodevelopment.

Association of Exposure to Ambient Air Pollutants With Cognitive Performance and Dementia Risk and the Mediating Role of Pulmonary Function: Evidence From the UK Biobank

BACKGROUND

The pathways by which air pollution affects cognition remain to be explored. This study aimed to explore how single air pollutants [including nitrogen oxide (NOX), nitrogen dioxide (NO2), particulate matter with a diameter of 2.5 micrometers (PM2.5), PM10, and PM2.5-10], and air pollution mixture could affect cognitive function and the incidence of dementia, and determine whether pulmonary function (PF) could play a mediating role in the relationship.

METHODS

Multiple statistical methods were employed to evaluate association of 5 air pollutants (NOX, NO2, PM2.5, PM10, and PM2.5-10) with cognitive function. Bootstrap method was used to estimate mediating role of PF in the association of air pollutants with cognition or the incidence of dementia.

RESULTS

A mixture of air pollutants was associated with performance on 5 cognitive tests, and global cognition (p < .05). Significantly negative association was also identified between mixture of air pollutants and PF (β= -0.020, 95% confidence interval (CI) = -0.029 to -0.011). In addition, as PF scores increase, performance on all cognitive tests significantly improve, although the risk of dementia correspondingly decreases. It was noted that PF was shown to mediate the effects of air pollution mixtures on all cognitive tests as well as global cognition. For global cognition, PF mediated 6.08% of the association. PF was also found to have a mediating role in the association between NOX, NO2, PM2.5, and the risk of dementia.

CONCLUSIONS

Mixed air pollution may impact cognitive function, with PF potentially mediating this relationship.

Maternal occupational exposure to carbonaceous nanoscale particles and neurodevelopmental outcomes in early childhood: Analysis of the French Longitudinal Study of Children - Elfe study

OBJECTIVE

To investigate the association between occupational exposures to carbonaceous unintentionally emitted nanoscale particles (UNPs) during pregnancy and the child's language development and behaviour at two years old.

METHODS

Using data from the French Longitudinal Study of Childhood - ELFE, we selected mothers who worked during pregnancy and their children. Exposure to carbonaceous UNPs was assessed by the MatPUF (job-exposure matrix for ultrafine particles). Children's lexical development was analysed using 'the Mac Arthur - Bates communicative development inventories-words and sentences-short form' (MB-CDI) in a multivariate binary logistic regression. Their risk for autism spectrum disorders was studied using 'the Modified-CHecklist for Autism in Toddler' (M-CHAT) according to the recommended thresholds (low risk = 0-2; intermediate risk = 3-6 and high risk = 7-23) in unordered multinomial logistic regression models.

RESULTS

Maternal occupational exposure to carbonaceous UNPs was associated with delayed child language development (ORadj: 1.34; 95 % CI: 1.00, 1.80) but not with behavioural disorders (autism spectrum disorders) at two years old.

CONCLUSION

This is the first epidemiological study to show a significant association between maternal occupational exposure to carbonaceous nanoscale particles and child language development at 2 years old.

Sensitive development windows of prenatal air pollution and cognitive functioning in preschool age Mexican children

Introduction

Neurotoxicity resulting from air pollution is of increasing concern. Considering exposure timing effects on neurodevelopmental impairments may be as important as the exposure dose. We used distributed lag regression to determine the sensitive windows of prenatal exposure to fine particulate matter (PM2.5) on children's cognition in a birth cohort in Mexico.

Methods

Analysis included 553 full-term (≥37 weeks gestation) children. Prenatal daily PM2.5 exposure was estimated using a validated satellite-based spatiotemporal model. McCarthy Scales of Children's Abilities (MSCA) were used to assess children's cognitive function at 4-5 years old (lower scores indicate poorer performance). To identify susceptibility windows, we used Bayesian distributed lag interaction models to examine associations between prenatal PM2.5 levels and MSCA. This allowed us to estimate vulnerable windows while testing for effect modification.

Results

After adjusting for maternal age, socioeconomic status, child age, and sex, Bayesian distributed lag interaction models showed significant associations between increased PM2.5 levels and decreased general cognitive index scores at 31-35 gestation weeks, decreased quantitative scale scores at 30-36 weeks, decreased motor scale scores at 30-36 weeks, and decreased verbal scale scores at 37-38 weeks. Estimated cumulative effects (CE) of PM2.5 across pregnancy showed significant associations with general cognitive index (C E ^ = -0.35, 95% confidence interval [CI] = -0.68, -0.01), quantitative scale (C E ^ = -0.27, 95% CI = -0.74, -0.02), motor scale (C E ^ = -0.25, 95% CI = -0.44, -0.05), and verbal scale (C E ^ = -0.2, 95% CI = -0.43, -0.02). No significant sex interactions were observed.

Conclusions

Prenatal exposure to PM2.5, particularly late pregnancy, was inversely associated with subscales of MSCA. Using data-driven methods to identify sensitive window may provide insight into the mechanisms of neurodevelopmental impairment due to pollution.

Associations between maternal exposure to air pollution during pregnancy and trajectories of infant growth: A birth cohort study

OBJECTIVE

We examined the relationships between infants' growth trajectories and prenatal exposure to air pollution, which is still under-investigated.

METHODS

A birth cohort study was constructed using medical records of pregnant women and infants born between 2015 and 2019 in Foshan, China. Using satellite-based spatial-temporal models, prenatal exposure to air pollutants including particulate matter with an aerodynamic dimension of < 2.5 µm (PM2.5), sulfur dioxide (SO2), nitrogen dioxide (NO2), and ozone (O3) was assessed at each woman's residence. Latent class growth modeling was used to identify trajectories of physical (body length and weight) growth and neurodevelopment, which were repeatedly measured within 1 year after birth. Logistic regression models were used to investigate the associations between prenatal exposure to air pollution and the risks of growth disorders, adjusting for an array of potential confounders.

RESULTS

We identified two growth trajectories for body length [normal: 3829 (93%); retardation: 288 (7%)], three for weight [normal: 2475 (59.6%); retardation: 390 (9.4%); overgrowth: 1287 (31%)], and two for neurodevelopment [normal: 956 (66.1%); retardation: 491 (33.9%)]. For exposure over whole pregnancy, SO2 was associated with an increased risk of body length retardation (OR for per 1 µg/m3 increment: 1.09, 95%CI: 1.01-1.17); PM2.5 (OR: 1.05, 95%CI: 1.03-1.07), SO2 (OR: 1.15, 95%CI: 1.08-1.22), and NO2 (OR: 1.05, 95%CI: 1.03-1.07) were positively associated with neurodevelopmental retardation. Such associations appeared stronger for exposures over the first and second trimesters. No significant associations were detected for weight growth.

CONCLUSIONS

Maternal exposure to air pollution during pregnancy was associated with higher risks of impairments in both physical growth, particularly body length, and neurodevelopment.

Association of air pollution exposure during pregnancy and early childhood with children's cognitive performance and behavior at age six

BACKGROUND

The impact of air pollution on neurodevelopment in children has attracted much attention in recent times. We aim to clarify the association between prenatal and postnatal air pollutant exposure and children's cognitive performance and behavior at age six.

METHODS

This study was conducted based on a birth cohort study in Japan. Children's intelligence quotient (IQ) was assessed using the Wechsler Intelligence Scale for Children and a score <85 was deemed as low intelligence. A score ≥60 on the Child Behavior Checklist indicated behavioral problems. Exposure to outdoor fine particulate matter (PM2.5) during pregnancy and early childhood was estimated using a spatiotemporal model, while indoor concentrations of air pollutants inside subjects' homes were measured for a week when the child was of ages 1.5 and 3. The associations of exposure to air pollution during pregnancy and after childbirth with cognitive performance and behavior were analyzed using logistic regression models.

RESULTS

The estimated exposure to outdoor PM2.5 during pregnancy and early childhood was not associated with decreased cognitive performance. However, exposure during the first trimester, 0-1 and 3-5 years of age was associated with children's externalizing problems (odds ratios (ORs) were 2.77 [95% confidence interval (CI): 1.05-7.29], 1.66 [95%CI: 1.05-2.62], and 1.80 [95%CI: 1.19-2.74] per interquartile range (IQR) increase, respectively). Exposure to indoor PM2.5 and coarse particles after childbirth was associated with lower full scale IQ (ORs were 1.46 [95%CI: 1.03-2.08] and 1.85 [95%CI: 1.12-3.07] per IQR increase, respectively). However, some inverse associations were also observed.

CONCLUSIONS

These results suggest associations between prenatal and postnatal exposure to outdoor air pollution and behavioral problems, and between indoor air pollution after childbirth and cognitive performance at age six. However, the effects of exposure to outdoor PM2.5 during pregnancy on cognitive performance were not observed.

Indoor air pollution exposure and early childhood development in the Upstate KIDS Study

BACKGROUND

Limited human studies have investigated the impact of indoor air pollution on early childhood neurodevelopment among the US population. We aimed to examine the associations between prenatal and postnatal indoor air pollution exposure and early childhood development in a population-based birth cohort.

METHODS

This analysis included 4735 mother-child pairs enrolled between 2008 and 2010 in the Upstate KIDS Study. Indoor air pollution exposure from cooking fuels, heating fuels, and passive smoke during pregnancy, and at 12 and 36 months after birth were assessed by questionnaires. Five domains of child development were assessed by the Ages and Stages Questionnaire at 4, 8, 12, 18, 24, 30, and 36 months. Generalized estimating equations were used to estimate odds ratios (ORs) and 95% confidence intervals (CIs), adjusting for potential confounders.

RESULTS

Exposure to unclean cooking fuels (natural gas, propane, or wood) throughout the study period was associated with increased odds of failing any development domain (OR = 1.28, 95% CI 1.07, 1.53), the gross motor domain (OR = 1.52, 95% CI: 1.09, 2.13), and the personal-social domain (OR = 1.36, 95% CI: 1.00, 1.85), respectively. Passive smoke exposure throughout the study period increased the odds of failing the problem-solving domain by 71% (OR = 1.71, 95% CI 1.01, 2.91) among children of non-smoking mothers. No association was found between heating fuel use and failing any or specific domains.

CONCLUSION

Unclean cooking fuel use and passive smoke exposure during pregnancy and early life were associated with developmental delays in this large prospective birth cohort.

Air pollution during the perinatal period and neurodevelopment in children: A national population study in Taiwan

AIM

To evaluate the association between ambient particulate matter no larger than 2.5 μm in diameter (PM2.5 ) during the prenatal and postnatal periods and infant neurodevelopmental parameters.

METHOD

We conducted a population-based birth cohort study using the Taiwan Birth Cohort Study. Participants were assessed for developmental conditions through home interviews at 6 months and 18 months of age. Exposure to PM2.5 of mothers and infants during perinatal periods was estimated using hybrid kriging/land-use regression. The exposure was linked to each participant by home address. Logistic regression was then conducted to determine the risk of neurodevelopmental delay in relation to PM2.5 .

RESULTS

A total of 17 683 term singletons without congenital malformations were included in the final analysis. PM2.5 during the second trimester was associated with increased risks of delays in gross motor neurodevelopmental milestones (adjusted odds ratio [aOR] 1.09 per 10 μg/m3 increase in exposure to PM2.5 ). Delayed fine motor development was also found to be related to exposure to PM2.5 in the second and third trimesters (aOR 1.06), as was personal-social skill (aOR 1.11 for the second trimester and 1.06 for the third). These neurodevelopmental parameters were unrelated to postnatal PM2.5 exposure.

INTERPRETATION

Exposure to ambient PM2.5 during pregnancy was significantly related to delay in gross motor, fine motor, and personal-social development in this population-based study.

WHAT THIS PAPER ADDS

Prenatal exposure to higher PM2.5 was associated with increased risk of delayed early neurodevelopment. The critical period for delayed gross motor development was the second trimester. The critical period for fine motor and personal-social development was the second and third trimesters.

Iodine Deficiency, Maternal Hypothyroxinemia and Endocrine Disrupters Affecting Fetal Brain Development: A Scoping Review

This scoping review critically discusses the publications of the last 30 years on the impact of mild to moderate iodine deficiency and the additional impact of endocrine disrupters during pregnancy on embryonal/fetal brain development. An asymptomatic mild to moderate iodine deficiency and/or isolated maternal hypothyroxinemia might affect the development of the embryonal/fetal brain. There is sufficient evidence underlining the importance of an adequate iodine supply for all women of childbearing age in order to prevent negative mental and social consequences for their children. An additional threat to the thyroid hormone system is the ubiquitous exposure to endocrine disrupters, which might exacerbate the effects of iodine deficiency in pregnant women on the neurocognitive development of their offspring. Ensuring adequate iodine intake is therefore essential not only for healthy fetal and neonatal development in general, but it might also extenuate the effects of endocrine disruptors. Individual iodine supplementation of women of childbearing age living in areas with mild to moderate iodine deficiency is mandatory as long as worldwide universal salt iodization does not guarantee an adequate iodine supply. There is an urgent need for detailed strategies to identify and reduce exposure to endocrine disrupters according to the "precautional principle".

Cognitive Development and Prenatal Air Pollution Exposure in the CHAMACOS Cohort

BACKGROUND

Because fine particulate matter [PM, with aerodynamic diameter ≤2.5μm (PM2.5)] is a ubiquitous environmental exposure, small changes in cognition associated with PM2.5 exposure could have great societal costs. Prior studies have demonstrated a relationship between in utero PM2.5 exposure and cognitive development in urban populations, but it is not known whether these effects are similar in rural populations and whether they persist into late childhood.

OBJECTIVES

In this study, we tested for associations between prenatal PM2.5 exposure and both full-scale and subscale measures of IQ among a longitudinal cohort at age 10.5 y.

METHODS

This analysis used data from 568 children enrolled in the Center for the Health Assessment of Mothers and Children of Salinas (CHAMACOS), a birth cohort study in California's agricultural Salinas Valley. Exposures were estimated at residential addresses during pregnancy using state of the art, modeled PM2.5 surfaces. IQ testing was performed by bilingual psychometricians in the dominant language of the child.

RESULTS

A 3-μg/m3 higher average PM2.5 over pregnancy was associated with -1.79 full-scale IQ points [95% confidence interval (CI): -2.98, -0.58], with decrements specifically in Working Memory IQ (WMIQ) and Processing Speed IQ (PSIQ) subscales [WMIQ -1.72 (95% CI: -2.98, -0.45) and PSIQ -1.19 (95% CI: -2.54, 0.16)]. Flexible modeling over the course of pregnancy illustrated mid-to-late pregnancy (months 5-7) as particularly susceptible times, with sex differences in the timing of susceptible windows and in which subscales were most affected [Verbal Comprehension IQ (VCIQ) and WMIQ in males; and PSIQ in females].

DISCUSSION

We found that small increases in outdoor PM2.5 exposure in utero were associated with slightly lower IQ in late childhood, robust to many sensitivity analyses. In this cohort there was a larger effect of PM2.5 on childhood IQ than has previously been observed, perhaps due to differences in PM composition or because developmental disruption could alter the cognitive trajectory and thus appear more pronounced as children get older. https://doi.org/10.1289/EHP10812.

Prenatal exposure to concentrated ambient PM2.5 results in spatial memory defects regulated by DNA methylation in male mice offspring

Ambient fine particulate matter (PM_2.5) exposures during pregnancy could lead to adverse birth outcomes, including neurobehavioral development defects. However, limited studies explored the effects and potential epigenetic mechanisms of maternal PM_2.5 exposure on offspring spatial memory defects. This study aims to explore the effects and underlying epigenetic mechanisms of maternal concentrated ambient PM_2.5 exposure in male mice offspring with spatial memory defects. Pregnant female C57BL/6 mice were exposed daily to concentrated ambient PM_2.5 (CAP) or filtered air (FA) throughout gestation, with the concentration of particulates (102.99 ± 78.74 μg/m³) and (2.78 ± 1.19 μg/m³), respectively. Adult male mice offspring were subsequently assessed for spatial learning and memory ability using Morris Water Maze tests and locomotor activities in open field tests. The hippocampus of the male mice offspring was harvested to test mRNA expression and DNA methylation. Results from the probe test of Morris Water Maze showed that the mice offspring in the CAP group had shorter swimming distance travelled in the target quadrant, shorter duration in the target quadrant, and less number of entries into the target quadrant (p < 0.05), suggesting spatial memory impairments. The acquisition trials of Morris Water Maze did not show a significant difference in learning ability between the groups. The mRNA level of interleukin 6 (IL-6) in the CAP group hippocampus (10.80 ± 7.03) increased significantly compared to the FA group (1.08 ± 0.43). Interestingly, the methylation levels of the CpG sites in the IL-6 promoter region declined significantly in the CAP group, (5.66 ± 0.83)% vs. (4.79 ± 0.48)%. Prenatal exposure to concentrated ambient PM_2.5 induced long-lasting spatial memory defects in male mice offspring. The underlying biological mechanism might be mediated by an inflammatory reaction which is regulated by DNA methylation.

Exposure to PM10, PM2.5, and NO2 and gross motor function in children: a systematic review and meta-analysis

Air pollution exposure has been related to negative gross motor development in children. However, there is currently a lack of conclusive evidence for such a relationship. We carried out a systematic review and meta-analysis using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) criteria to examine whether exposure to air pollution has an impact on children's gross motor development. Of the 9746 papers found, 7 studies examined the impact of air pollutant characteristics, such as PM_2.5, PM₁₀, and NO₂, on children's gross motor development. The results of the study reveal a significant association between air pollutants and an increased likelihood of negative gross motor development. PM₁₀ was discovered to be considerably riskier for children's gross motor development (effect: - 1.83, 95% CI: - 3.04, - 0.62, p value = 0.002). Additionally, NO₂ exhibited indications of a tendency to be connected to a detrimental impact on children's gross motor development (effect - 0.18, 95% CI: - 0.42, 0.07, p value = 0.097).  Conclusion: Our study indicates that exposure to PM₁₀, PM_2.5, and NO₂, especially PM_2.5 and PM₁₀, is negatively associated with children's gross motor development. However, further research is required to determine how exposure to prenatal air pollution affects children's gross motor development. What is Known - What is New: • In this study, we provide an overview of emerging data related to PM10, PM2.5, and NO2 exposure in child development, especially on the gross motor function that continues to emerge, and key findings are highlighted. • Additionally, we summarize the evidence on the underlying effect of air pollution on gross motor function from human studies.. • Overall, we emphasize that evidence from human studies is critical in suggesting detrimental child health outcomes of an action to promote preventive strategies that will effectively protect children's health..

Prenatal exposure to ambient air pollution is associated with neurodevelopmental outcomes at 2 years of age

BACKGROUND

Higher prenatal ambient air pollution exposure has been associated with impaired neurodevelopment in preschoolers and school-aged children. The purpose of this study was to explore the relationships between prenatal ambient air pollution exposure and neurodevelopment during infancy.

METHODS

This study examined 161 Latino mother-infant pairs from the Southern California Mother's Milk Study. Exposure assessments included prenatal nitrogen dioxide (NO₂) and particulate matter smaller than 2.5 and 10 microns in diameter (PM_2.5 and PM₁₀, respectively). The pregnancy period was also examined as three windows, early, mid, and late, which describe the first, middle, and last three months of pregnancy. Infant neurodevelopmental outcomes at 2 years of age were measured using the Bayley-III Scales of Infant and Toddler Development. Multivariable linear models and distributed lag linear models (DLM) were used to examine relationships between prenatal exposures and neurodevelopmental scores, adjusting for socioeconomic status, breastfeeding frequency, time of delivery, pre-pregnancy body mass index, and infant birthweight and sex.

RESULTS

Higher prenatal exposure to PM₁₀ and PM_2.5 was negatively associated with composite cognitive score (β = -2.01 [-3.89, -0.13] and β = -1.97 [-3.83, -0.10], respectively). In addition, higher average prenatal exposure to PM₁₀ was negatively associated with composite motor (β = -2.35 [-3.95, -0.74]), scaled motor (β = -0.77 [-1.30, -0.24]), gross motor (β = -0.37 [-0.70, -0.04]), fine motor (β = -0.40 [-0.71, -0.09]), composite language (β = -1.87 [-3.52, -0.22]), scaled language (β = -0.61 [-1.18, -0.05]) and expressive communication scaled scores (β = -0.36 [-0.66, -0.05]). DLMs showed that higher prenatal air pollution exposure during mid and late pregnancy was inversely associated with motor, cognitive, and communication language scores.

CONCLUSIONS

Higher exposure to air pollutants during pregnancy, particularly in the mid and late prenatal periods, was inversely associated with scaled and composite motor, cognitive, and language scores at 2 years. These results indicate that prenatal ambient air pollution may negatively impact neurodevelopment in early life.

The association of air pollutants with hospital outpatient visits for child and adolescence psychiatry in Shenzhen, China

BACKGROUND

Although exposure to ambient air pollution has been associated with mental disorder, little is known about its potential effects on children and adolescents, especially in Chinese population. We aimed to reveal the relationship of air pollutants with hospital outpatient visits for child and adolescence psychiatry (HOVCAP) in Shenzhen.

METHODS

A case-crossover study based on time-series data was applied, and a distributed lag non-linear model (DLNM) was used to evaluate the non-linear and delayed effects of 4 major air pollutants (NO₂, PM_2.5, SO₂ and O₃) on HOVCAP. Least absolute shrinkage and selection operator (LASSO) regression was used to control the multicollinearity between covariates and to filter variables.

RESULT

A total of 94,660 cases aged 3-18 were collected from 2014 to 2019 in the Mental Health Center of Shenzhen. Results of pollutants at mode value (M₀) showed that in the single lag effect result, when the average daily concentration of NO₂ at 24 μg/m³, there was a significant effect on HOVCAP over lag 1, lag 4 and lag 5, respectively. The cumulative RR of NO₂ M₀ value to the outpatient visits were 1.438 (1.137-1.818) over lag 0-2, 1.454 (1.120-1.887) over lag 0-3, 1.466 (1.084-1.982) over lag 0-4, 1.680 (1.199-2.354) over lag 0-5, 1.993 (1.369-2.903) over lag 0-6, and 2.069 (1.372-3.119) over lag 0-7. However, PM_2.5, SO₂, O₃ were not associated with HOVCAP over neither single lag effects nor cumulative effects. The RR values both shown an increase either when NO₂ increases by 10 units or when the maximum concentration of NO₂ is reached.

CONCLUSION

Our study suggests that exposure to the normal air quality of NO2 in Shenzhen may associated with the risk of HOVCAP. However, PM2.5, SO2, O3 were not associated with HOVCAP.

Acute effects of ambient nitrogen dioxide exposure on serum biomarkers of nervous system damage in healthy older adults

Ambient nitrogen dioxide (NO₂)-induced adverse health effects have been studied, but documented evidence on neural systems is limited. This study aimed to determine the acute effect of NO₂ exposure on nervous system damage biomarker levels in healthy older adults. Five rounds of follow-up among 34 healthy retired people were scheduled from December 2018 to April 2019 in Xinxiang, China. The real-time NO₂ concentrations were measured using a fixed site monitor. Serum samples were acquired during each round to measure nervous system damage biomarker levels: brain-derived neurotrophic factor (BDNF), neurofilament light chain (NfL), neuron-specific enolase (NSE), protein gene product 9.5 (PGP9.5), and S100 calcium-binding protein B (S100B). A linear mixed-effect model was incorporated to analyze the association between short-term NO₂ exposure and serum concentrations of the above-mentioned biomarkers. Stratification analysis based on sex, educational attainment, glutathione S-transferase theta 1 gene (GSTT1) polymorphism, and physical activity intensity was conducted to explore their potential modification effect. The NO₂ concentration ranged from 34.7 to 59.0 µg/m³ during the study period. Acute exposure to ambient NO₂ was significantly associated with elevated serum levels of NfL, PGP9.5, and BDNF. In response to a 10 µg/m³ increase in NO₂ concentration, NfL and PGP9.5 levels increased by 76 % (95 % confidence interval [CI]: 12-140 %) and 54 % (95 % CI: 1-107 %) on the lag0 day, respectively, while BDNF levels increased by 49 % (95 % CI: 2-96 %) at lag4 day. The estimated effect of NO₂ on NSE levels in GSTT1-sufficient participants was significantly higher than that in GSTT1-null participants. Intriguingly, the estimation of NO₂ on PGP9.5 levels in females was significantly higher than that in males. Most two-pollutant models showed robust results, except for O₃, which might have had confounding effects on NO₂-induced BDNF stimulation. In summary, acute exposure to NO₂ was associated with increased levels of serum nervous system damage biomarker levels including NFL, PGP9.5, and BDNF. The present study provided insights into NO₂ exposure-induced adverse neural effects.

Neurodevelopmental toxicity induced by airborne particulate matter

Airborne particulate matter (PM), the primary component associated with health risks in air pollution, can negatively impact human health. Studies have shown that PM can enter the brain by inhalation, but data on the exact quantity of particles that reach the brain are unknown. Particulate matter exposure can result in neurotoxicity. Exposure to PM poses a greater health risk to infants and children because their nervous systems are not fully developed. This review paper highlights the association between PM and neurodevelopmental toxicity (NDT). Exposure to PM can induce oxidative stress and inflammation, potentially resulting in blood-brain barrier damage and increased susceptibility to development of neurodevelopmental disorders (NDD), such as autism spectrum disorders and attention deficit disorders. In addition, human and animal exposure to PM can induce microglia activation and epigenetic alterations and alter the neurotransmitter levels, which may increase risks for development of NDD. However, the systematic comparisons of the effects of PM on NDD at different ages of exposure are deficient. The elucidation of PM exposure risks and NDT in children during the early developmental stages are of great importance. The synthesis of current research may help to identify markers and mechanisms of PM-induced neurodevelopmental toxicity, allowing for the development of strategies to prevent permanent damage of developing brain.

Effects of prenatal exposure to PM2.5 and its composition on cognitive and motor functions in children at 12 months of age: The Shanghai Birth Cohort Study

BACKGROUND

Prenatal fine particulate matter (PM_2.5) exposure has been linked to infant cognitive and motor functions, but the effects of PM_2.5 chemical composition remain unclear.

OBJECTIVES

We aimed to explore the associations of prenatal PM_2.5 and its composition exposure with infant cognitive and motor functions.

METHODS

We studied 2,435 mother-infant pairs in the Shanghai Birth Cohort Study. PM_2.5 and its seven compositions [primary particles (black carbon, mineral dust and sea salts) and secondary particles (NH₄⁺, NO₃^-, SO₄^2- and organic matter)] during thethreetrimesters ofpregnancy were retrieved from the V4.CH.03 product developed by using a combined geoscience-statistical method. At the 12-month-old follow-up, infant cognitive and motor functions in five domains were assessed using the Ages and Stages Questionnaire (ASQ). We used multivariable linear regressions to estimate the effects of PM_2.5 and its composition on the ASQ scores, for all infants and stratifying by sex and breastfeeding duration.

RESULTS

PM_2.5 exposure was negatively associated with gross motor, problem-solving and personal-social scores for all infants. PM_2.5 compositions were inversely associated with ASQ scores in all five domains, and the effects of different compositions varied across domains. Specifically, all compositions except organic matter were correlated with lower problem-solving scores [e.g., ( [Formula: see text]  =  - 10.79, 95 % CI: -17.40, -4.18) ∼ ( [Formula: see text]  =  - 4.68, 95 % CI: -7.84, -1.53); for each 10 μg/m³ increase in PM_2.5 compositions during the third trimester]. Primary and some secondary particles (organic matter, NO₃^-) were related to lower gross motor scores. Secondary particles were also inversely associated with communication (organic matter and NO₃^-), fine motor (NH₄⁺, NO₃^-, SO₄^2-) and personal-social (NH₄⁺) scores. Additionally, boys and infants breastfed for < 6 months appeared to be more susceptible.

CONCLUSIONS

We found negative associations of PM_2.5 and its compositions with infant cognitive and motor functions over a range of domains, especially the problem-solving domain.

Air quality improvement and cognitive function benefit: Insight from clean air action in China

INTRODUCTION

Epidemiological evidence suggests associations between long-term exposure to air pollution and accelerated cognitive decline. China implemented a strict clean air action plan in 2013; however, it is unclear whether the improvement of air quality has alleviated cognitive impairment in the population.

METHODS

From the China Health and Retirement Longitudinal Study, 8536 Chinese adults were enrolled in 2011 and followed up in 2015. Satellite-based spatiotemporal models were used to estimate exposure to air pollutants (including particles with diameters ≤1.0 μm [PM₁], ≤2.5 μm [PM_2.5], ≤10 μm [PM₁₀], nitrogen dioxide [NO₂], and ozone [O₃]). Cognitive function was evaluated using a structured questionnaire in three dimensions: episodic memory, orientation and attention, and visuoconstruction. The associations between changes in the levels of air pollutants and cognitive function were elucidated by a logistic model. The Bayesian Kernel Machine Regression (BKMR) model was applied to evaluate the cumulative effect of air pollutants.

RESULTS

The mean (standard deviation) age of all participants was 58.6 (8.7) years. The odds ratio (95% confidence interval) between the highest and the lowest quartile of PM₁ exposure reduction for cognitive impairment was 0.46 (0.41, 0.53) after adjusting for confounders. Similar protective effects of cognitive function were observed with the decrease in the level of PM_2.5 (0.34 [0.30, 0.39]), PM₁₀ (0.54 [0.48, 0.62]), and NO₂ (0.59 [0.51, 0.67]), while the reduction in O₃ appeared to be less related to changes in cognitive function (OR: 0.97 [0.85, 1.10]). The protective association of PM₁ reduction was stronger in males than in females. Decreased in PM_2.5 dominate the cognitive function benefit relative to PM₁, PM₁₀, NO₂.

CONCLUSIONS

The implementation of the clean air action plan led to a significant reduction in PM₁, PM_2.5, PM₁₀, and NO₂, which could slow the decline of cognitive function, while a reduction in O₃ may not.

The effect of air pollution and emotional and behavioral problems on preschoolers' overweight and obesity

Childhood overweight and obesity (OWO) has risen dramatically in both developed and developing countries over the past few decades, creating a huge burden of disease. Ambient air pollution and emotional and behavioral problems are important influencing factors of OWO in preschoolers, but few studies have evaluated the impact of air pollution and emotional and behavioral problems on OWO of preschoolers in rural areas and their potential interactions. This study selected 3802 preschool children from 26 kindergartens in 4 rural areas of Anhui Province for a cross-sectional study. A total of 3636 individuals were included in the final analysis. In this study, outdoor air pollutants (PM_2.5 and O₃) were derived from the China Air Pollution Tracking (TAP) data set, matching preschoolers' external air pollution exposure according to their kindergarten address codes to neighborhoods or administrative villages. OWO were assessed based on WHO Child Growth and Development Standards. Generalized linear model (GLM) and interplot model were used to evaluate the separate effects and potential interactions of air pollutants and emotional and behavioral problems on preschoolers' OWO. In the separate analysis, we found a significant positive association between air pollution and emotional and behavioral problems and OWO among preschoolers. In the interaction analysis, air pollution could enhance the positive effect of emotional and behavioral problems on OWO in preschoolers. In addition, the effect of air pollution and emotional and behavioral problems on overweight and obesity was stronger in preschoolers aged 5 to 6 years. Finally, we also found a stronger positive association between emotional and behavioral problems among girls, macrosomia, non-left-behind children, and preschoolers without eating problems. This study provided a scientific basis for the control of air pollution and overweight and obesity among preschool children in Anhui Province.

Maternal exposure to air pollution during pregnancy and child's cognitive, language, and motor function: ECLIPSES study

Prenatal exposure to air pollution, even at low levels, has been associated with negative effects on a child's neuropsychological functioning. The present work aimed to investigate the associations between prenatal exposure to air pollution on a child's cognitive, language, and motor function at 40 days of age in a highly exposed area of Spain. From the ECLIPSES study population, the present work counted 473 mother-child pairs. Traffic-related air pollution levels at home addresses during the whole pregnancy were estimated including particulate matter (PM) with an aerodynamic diameter <2.5 μm (PM_2.5), <10 μm (PM₁₀) and 2.5-10 μm (PM_coarse), PM_2.5absorbance, nitrogen dioxide (NO₂), other nitrogen oxides (NO_x), and ozone (O₃) using land-use regression models developed within ESCAPE and ELAPSE projects. Children's cognitive, language, and motor functions were assessed using the Bayley Scales of Infant Development 3rd edition (BSID-III) at around 40 days of age. Linear regression models were adjusted for maternal biological, sociodemographic and lifestyle characteristics, area deprivation index, and amount of greenness around the home's address. All air pollutants assessed, except PM_2.5 absorbance, were associated with lower motor function in children, while no association was observed between prenatal exposure to air pollution and cognitive and language functions. This finding highlights the need to continue raising awareness of the population-level impact that maternal exposure to air pollution even at low levels can have on the neuropsychological functions of children.

In-utero exposure to indoor air pollution or tobacco smoke and cognitive development in a South African birth cohort study

BACKGROUND AND AIMS

There is increasing evidence indicating that air pollution exposure is associated with neuronal damage. Since pregnancy is a critical window of vulnerability, air pollution exposure during this period could have adverse effects on neurodevelopment. This study aims 1) to analyze associations of prenatal exposure to indoor air pollution (particulate matter with diameters ≤10 μm, PM10) and tobacco smoke with neurodevelopment and 2) to determine whether these associations are mediated by deviations of epigenetic gestational age from chronological gestational age (ΔGA).

METHODS

Data of 734 children from the South African Drakenstein Child Health Study were analyzed. Prenatal PM10 exposure was measured using devices placed in the families' homes. Maternal smoking during pregnancy was determined by maternal urine cotinine measures. The Bayley Scales of Infant and Toddler Development III (BSID-III) was used to measure cognition, language and motor development and adaptive behavior at two years of age. Linear regression models adjusted for maternal age, gestational age, sex of child, ancestry, birth weight/length, and socioeconomic status were used to explore associations between air pollutants and BSID-III scores. A mediation analysis was conducted to analyze if these associations were mediated by ΔGA using DNA methylation measurements from cord blood.

RESULTS

An increase of one interquartile range in natural-log transformed PM10 (lnPM10; 1.58 μg/m3) was significantly associated with lower composite scores in cognition, language, and adaptive behavior sub-scores (composite score β-estimate [95%-confidence interval]: -0.950 [-1.821, -0.120]). Maternal smoking was significantly associated with lower adaptive behavior scores (-3.386 [-5.632, -1.139]). Associations were not significantly mediated by ΔGA (e.g., for PM10 and cognition, proportion mediated [p-value]: 4% [0.52]).

CONCLUSION

We found an association of prenatal exposure to indoor air pollution (PM10) and tobacco smoke on neurodevelopment at two years of age, particularly cognition, language, and adaptive behavior. Further research is needed to understand underlying biological mediators.

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

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

Early-life environmental exposures and anaemia among children under age five in Sub-Saharan Africa: An insight from the Demographic & Health Surveys

BACKGROUND

Reports show that the majority (60%) of children under age five years in Sub-Saharan Africa are anaemic. Studies in the region have mainly focused on the effect of individual, maternal and household socioeconomic status on the prevalence of anaemia. Currently, there is limited understanding of the association between early-life environmental exposures and anaemia among children in Sub-Saharan Africa.

OBJECTIVE

The study examines the association between early-life environmental exposures and anaemia among children under five in Sub-Saharan Africa.

METHODS

The study used health and demographic data from the Demographic and Health Survey (DHS) program and environmental data from NASA's Geospatial Interactive Online Visualization ANd aNalysis Infrastructure (GIOVANNI) and Atmospheric Composition Analysis Group. Three exposure periods were defined for the study, namely: in-utero, post-utero and cumulative life exposures. Multilevel mixed-effect models were used to assess the associations between environmental exposures and anaemia in each exposure period.

RESULTS

The findings show that 63% of children in the study were anaemic. It also reveals that mean PM 2.5 exposure for in-utero (34.93 μgm^-3), post-utero (35.23 μgm^-3) and cumulative exposure (35.08 μgm^-3) were seven times higher than the new air quality guideline WHO recommended. A 10 μgm^-3 increase in in-utero, post-utero and cumulative PM 2.5 exposures was associated with 4% to 5% increase in the prevalence of anaemia among children. A 10ppbv increase in in-utero, post-utero and cumulative carbon monoxide exposures was associated with 1% increase in the prevalence of anaemia among children. The spatial risk distribution maps show that socioeconomic factors modify the spatial risk distribution pattern.

CONCLUSION

The findings of the study suggest that early-life exposure to ambient air pollution is significantly associated with anaemia among children in Sub-Saharan Africa. Thus, policies aimed at addressing air quality should be incorporated into targeted interventions for anaemia among children in the region.

Combined toxicity of air pollutants related to e-waste on inflammatory cytokines linked with neurotransmitters and pediatric behavioral problems

E-waste usually refers to the discarded electrical or electronic equipment that is no longer used. Informal e-waste recycling methods, such as burning, roasting, acid leaching, and shredding, had resulted in serious air pollution, which is a prominent risk factor for children's health. However, the combined toxicity of air pollutants on children's behavioral health remains unclear. This study collected data on air pollution exposure, calculated the average daily dose (ADD) based on these air pollutants for children in Guiyu (e-waste group, n = 112) and Haojiang (reference group, n = 101), then assessed children's behavioral health using the Strengths and Difficulties Questionnaire (SDQ), and further estimated the associations of ADD, inflammatory cytokines, neurotransmitters, and children's behavioral problems. Compared with Haojiang, Guiyu has poorer air quality and higher levels of ADD, inflammatory cytokines (such as IL-1β, IL-6, and TNF-α), neurotransmitters (such as DA and SP), and SDQ scores, but lower levels of serum neuropeptide Y (NPY) levels. Spearman correlation analyses indicated that there were significant relationships among inflammatory cytokines, neurotransmitters, and behavioral scores. Multiple linear regression analyses showed that each unit increase in ADD was associated with serum levels of DA and SP, the serum NPY subsequently changed by B (95% CI): 0.99 (0.14, 1.84) nmol/L, 0.25 (0.08, 0.42) ng/mL, and - 0.16 (-0.26, -0.05) ng/mL, respectively. After adjustment for confounders, logistic regression analyses suggested that with each one-fold increase in ADD was associated with the risk of emotional symptoms [OR (95% CI): 18.15 (2.72, 121.06)], hyperactivity-inattention [13.64 (2.28, 81.65)] and total difficulties [8.90 (1.60, 49.35)] and prosocial behavior [- 7.32 (-44.37, -1.21)]. Taken together, this study demonstrates that combined exposure to air pollutants may alter the levels of inflammatory cytokines and serum neurotransmitter to subsequently impact behavioral health in children.

Prenatal and early postnatal exposure to ambient particulate matter and early childhood neurodevelopment: A birth cohort study

Adverse impacts of prenatal or postnatal ambient particulate matter exposure have been identified on offspring neurodevelopment. However, it is unclear whether the effect in the two exposure periods is different for early childhood neurodevelopment. This study aimed to evaluate and compare the associations of prenatal and early postnatal exposure to ambient particulate matter with offspring neurodevelopment at 2 years of age and to identify which period was more sensitive to the effects of ambient particulate matter on offspring neurodevelopment. A total of 1331 mother-child pairs from a birth cohort were included in this study from October 2013 to September 2014 in Wuhan, China. The concentrations of ambient daily fine particulate matter (PM_2.5) and particulate matter less than 10 μm in aerodynamic diameter (PM₁₀) at each participant's home address during pregnancy and the first two years after birth were estimated by land-use regression models (LUR). Offspring neurodevelopment was measured by the Chinese revision of Bayley Scale of Infant Development (BSID-CR) for each child at 2 years of age. Mental developmental index (MDI) and psychomotor developmental index (PDI) from the BSID-CR were used as outcome variables. A generalized estimating equation (GEE) model was used to estimate the associations of prenatal and postnatal PM_2.5 and PM₁₀ exposure with offspring neurodevelopment. After adjusting for potential confounders, we found that both prenatal and early postnatal exposure to PM_2.5 and PM₁₀ were associated with decreased offspring MDI and PDI scores. Compared with prenatal exposure, the associations of early postnatal exposure to PM_2.5 and PM₁₀ with offspring MDI and PDI were stronger. This study indicates that exposure to ambient particulate matters, mainly during early postnatal period and to a lesser extent prenatally, is associated with impaired offspring neurodevelopment.

In-utero exposure to air pollution and early-life neural development and cognition

Air pollution remains one of the major health threats around the world. Compared to adults, foetuses and infants are more vulnerable to the effects of environmental toxins. Maternal exposure to air pollution causes several adverse birth outcomes and may lead to life-long health consequences. Given that a healthy intrauterine environment is a critical factor for supporting normal foetal brain development, there is a need to understand how prenatal exposure to air pollution affects brain health and results in neurological dysfunction. This review summarised the current knowledge on the adverse effects of prenatal air pollution exposure on early life neurodevelopment and subsequent impairment of cognition and behaviour in childhood, as well as the potential of early-onset neurodegeneration. While inflammation, oxidative stress, and endoplasmic reticulum are closely involved in the physiological response, sex differences also occur. In general, males are more susceptible than females to the adverse effect of in-utero air pollution exposure. Considering the evidence provided in this review and the rising concerns of global air pollution, any efforts to reduce pollutant emission or exposure will be protective for the next generation.

Associations of Pre- and Postnatal Air Pollution Exposures with Child Behavioral Problems and Cognitive Performance: A U.S. Multi-Cohort Study

BACKGROUND

Population studies support the adverse associations of air pollution exposures with child behavioral functioning and cognitive performance, but few studies have used spatiotemporally resolved pollutant assessments.

OBJECTIVES

We investigated these associations using more refined exposure assessments in 1,967 mother-child dyads from three U.S. pregnancy cohorts in six cities in the ECHO-PATHWAYS Consortium.

METHODS

Pre- and postnatal nitrogen dioxide (NO2) and particulate matter (PM) ≤2.5μm in aerodynamic diameter (PM2.5) exposures were derived from an advanced spatiotemporal model. Child behavior was reported as Total Problems raw score using the Child Behavior Checklist at age 4-6 y. Child cognition was assessed using cohort-specific cognitive performance scales and quantified as the Full-Scale Intelligence Quotient (IQ). We fitted multivariate linear regression models that were adjusted for sociodemographic, behavioral, and psychological factors to estimate associations per 2-unit increase in pollutant in each exposure window and examined modification by child sex. Identified critical windows were further verified by distributed lag models (DLMs).

RESULTS

Mean NO2 and PM2.5 ranged from 8.4 to 9.0 ppb and 8.4 to 9.1 μg/m3, respectively, across pre- and postnatal windows. Average child Total Problems score and IQ were 22.7 [standard deviation (SD): 18.5] and 102.6 (SD: 15.3), respectively. Children with higher prenatal NO2 exposures were likely to have more behavioral problems [β: 1.24; 95% confidence interval (CI): 0.39, 2.08; per 2 ppb NO2], particularly NO2 in the first and second trimester. Each 2-μg/m3 increase in PM2.5 at age 2-4 y was associated with a 3.59 unit (95% CI: 0.35, 6.84) higher Total Problems score and a 2.63 point (95% CI: -5.08, -0.17) lower IQ. The associations between PM2.5 and Total Problems score were generally stronger in girls. Most predefined windows identified were not confirmed by DLMs.

DISCUSSION

Our study extends earlier findings that have raised concerns about impaired behavioral functioning and cognitive performance in children exposed to NO2 and PM2.5 in utero and in early life. https://doi.org/10.1289/EHP10248.

Air pollution, children's academic achievement and the potential mediating role of preterm birth

INTRODUCTION

Previous research has observed relationships between higher prenatal exposure to air pollutants and neurodevelopmental and academic outcomes later in childhood. Identifying intermediate outcomes mediating this relationship would inform prevention and intervention efforts. We aimed to investigate if previously observed associations between prenatal exposure to common urban air pollutants, diesel and perchloroethylene, and performance on third grade standardized tests were mediated through increased risk of preterm birth.

METHODS

Data from the 1994-1998 birth cohorts within the New York City Longitudinal Study of Early Development were included in this analysis. Exposure was determined by linking the mother's residence at the time of delivery to the U.S. EPA's 1996 National Air Toxic Assessment of estimated ambient concentrations of diesel and perchloroethylene. Children's third grade standardized math and language tests were used as the markers for academic achievement. Missing data on covariates were imputed, while participants with missing information on gestational age and test scores were excluded. Linear regression models and causal mediation analysis were used to examine potential mediation by preterm birth.

RESULTS

In total, 187,723 and 196,122 participants were included in language and math analyses, respectively. Children with exposure to the fourth quartile of diesel or perchloroethylene had approximately 0.03 (95%CI: 0.02, 0.04) lower math z-scores when compared to individuals with exposure in the first quartile, although there was no consistent decreasing trend in math z-scores over increasing quartiles of diesel or perchloroethylene. We did not find evidence of mediation by preterm birth or exposure-mediator interaction in our models.

CONCLUSION

We did not find evidence that observed relationships between exposure to common urban air pollutants and test z-scores in childhood were mediated through an increased risk of preterm birth. This suggests other pathways between early exposure to air pollution and neurodevelopment should be investigated with causal mediation approaches.

Prenatal exposure to air pollution and neurodevelopmental delay in children: A birth cohort study in Foshan, China

BACKGROUND

Prenatal exposure to air pollution may have adverse effects on neurodevelopment in children, but epidemiological evidence remains inconclusive.

OBJECTIVE

To investigate the associations between prenatal air pollution exposure and neurodevelopmental delay.

METHODS

We conducted a birth cohort study based on pregnancy and birth registry in Foshan, China. Exposure to particulate matter of aerodynamic diameter < 1 μm, 2.5 μm, 10 μm (PM₁, PM_2.5, PM₁₀), nitrogen dioxide (NO₂) and sulfur dioxide (SO₂) over pregnancy (trimester 1, 2, 3 and entire pregnancy) was estimated at each woman's residential address using spatial-temporal models. Neurodevelopmental assessment was performed by pediatricians using a five-domain scale and developmental quotient (DQ) was calculated as a global measure. Logistic regression models were used to investigate the associations between prenatal air pollution exposure and neurodevelopmental delay (DQ < 75) with adjustment for potential confounders.

RESULTS

We included 15,778 child-mother pairs in this analysis, including 1013 children with neurodevelopmental delay. We observed positive associations between prenatal exposure to air pollution and higher risk of neurodevelopmental delay in children. The adjusted odds ratios (ORs) per 10 μg/m³ elevation in PM₁, PM_2.5, PM₁₀, NO₂ and SO₂ in entire pregnancy were 1.12 [95% confidence interval (CI): 1.01, 1.25], 1.15 (95% CI: 1.03, 1.29), 1.12 (95% CI: 1.02, 1.24), 1.06 (95% CI: 0.94, 1.19) and 1.58 (95% CI: 1.11, 2.23), respectively. The associations were more robust for trimester 1 and trimester 2, especially trimester 1.

CONCLUSIONS

Exposure to air pollution during pregnancy, especially early-to-mid pregnancy, was associated with increased risk of neurodevelopmental delay in young children, indicating its adverse neurodevelopmental effects in early-life stage.

Prenatal Exposure to Traffic-Related Air Pollution and the DNA Methylation in Cord Blood Cells: MOCEH Study

Particulate matter with a diameter of ≤10 µm (PM₁₀) and nitrogen dioxide (NO₂) affect the DNA methylation in the fetus, but epigenetic studies regarding prenatal exposure to air pollution in Asia are lacking. Therefore, this study aimed to assess whether there is any association between the ambient concentrations of PM₁₀ and NO₂ and CpG methylation in the cord blood DNA by using a Korean birth cohort. The concentrations of the air pollutants were incorporated into the final LUR model by using the maternal address data. The methylation level was determined using HumanMethylationEPIC BeadChip and a linear regression analysis model. A multipollutant model including both PM₁₀ and NO₂ and models with single pollutants were used for each trimester exposure. The number of differentially methylated positions was the largest for midpregnancy exposure in both the single pollutant models and the multipollutant regression analysis. Additionally, gene-set analysis regarding midpregnancy exposure revealed four gene ontology terms (cellular response to staurosporine, positive regulation of cytoskeleton organization, neurotransmitter transport, and execution phase of apoptosis). In conclusion, these findings show an association between prenatal PM₁₀ and NO₂ exposure and DNA methylation in several CpG sites in cord blood cells, especially for midpregnancy exposure.

Assessing the causal effects of long-term exposure to PM2.5 during pregnancy on cognitive function in the adolescence: Evidence from a nationwide cohort in China

The effects of air pollution on adolescents need further consideration. Although there is evidence that maternal exposure to air pollution may affect the cognitive function of offspring, relevant studies remain limited and inconsistent, with a lack of studies assessing the causal effects and evidence from developing countries. Using data from Chinese Family Panel Studies, a representative Chinese nationwide cohort study, OLS combined with instrumental variable + two-stage least square (IV+2SLS) was used to explore the causal effects of exposure to PM_2.5 concentrations during pregnancy on the cognitive function of offspring when they become adolescents. After detailed argumentation and multiple testing, Planetary Boundary Layer Height (PBLH) and Surface Pressure (SP) were selected as the instrumental variables for this study. One thousand five hundred fifty-five adolescents participated in this study, with a mean age of 13.3 years (sd = 2.3). There were 706 females (45.4%), the mean maternal PM_2.5 exposure concentration was 64.9 μg/m³, and recorded a mean cognitive function score of 38.1 (sd = 9.4). The OLS results found that maternal exposure to air pollution increased cognitive function in offspring adolescents, corroborating the presence of endogeneity. Multi-domain knowledge, the results of the weak instrumental variable assessments of F-tests (F = 237 > 10) and Stock-yogo tests (minimum eigenvalue statistic = 153.16 > 16.38), and the results of the Hansen J overidentification test (p > 0.05) verified the plausibility and validity of the instrumental variables. The IV+2SLS results, following causal modeling, showed that PM_2.5 exposure during pregnancy impairs the cognitive ability of offspring adolescents (β = -0.040, p < 0.05). Robustness tests also validated the results. This study provides important policy implications for developing countries on protecting their adolescents and reminds parents that the protection of adolescents from air pollution should begin from conception.

Maternal and Childhood Ambient Air Pollution Exposure and Mental Health Symptoms and Psychomotor Development in Children: An Australian Population-Based Longitudinal Study

BACKGROUND

Accumulating evidence indicates early life exposure to air pollution, a suspected neurotoxicant, is negatively associated with children's neurodevelopment.

OBJECTIVES

To explore the role of multiple exposure periods to ambient particulate matter with diameter <2.5 μm (PM_2.5) and nitrogen dioxide (NO₂) on emotion and behaviour, and early development in children <13 years.

METHODS

We used data from Mothers and their Children's Health (MatCH) study, a 2016/17 sub-study from a prospective longitudinal study, the Australian Longitudinal Study on Women's Health. Annual PM_2.5 and NO₂ estimates since 1996 were obtained from a land-use regression model. Maternal residential proximity to roadways were used as a proxy measure of exposure to traffic-related air pollution. Child outcomes were maternal-rated emotional and behavioural problems (Strengths and Difficulties Questionnaire; SDQ, aged 2-12 years, n = 5471 children) and developmental delay in communication and gross motor skills (Ages and Stages Questionnaire; ASQ, aged 1-66 months, n = 1265 children). Defined exposure periods were early life exposure ('during pregnancy' and 'first year of life') and 'children's lifetime exposure'. Ambient air pollution was divided into tertiles and logistic regression was performed to estimate odds ratio (OR) for each child outcome, adjusting for potential confounders.

RESULTS

Children exposed to moderate and high PM_2.5 exposure, compared to low exposure, across all periods, had higher odds of emotional and behavioural problems, and gross motor delay. Children's lifetime exposure to moderate levels of PM_2.5 (5.9-7.1 µg/m³) was associated with 1.27 (95% confidence interval 1.03, 1.57) fold higher odds of emotional/behavioural problems. Similar associations were found for moderate PM_2.5 levels at 'first year of life' in a two-pollutant model only (OR: 1.30; 1.05, 1.60). However, there was insufficient evidence to suggest that NO₂ exposure or living within 200 m of major roads was associated with emotional and behaviour problems or developmental delay across any exposure periods.

CONCLUSION

We found isolated evidence that early life and childhood exposure to PM_2.5 may be associated with emotional and behavioural problems and delays in gross motor skills, but most associations were null. Due to the limited number of longitudinal studies on low-exposure settings, further studies with more temporally refined exposure assessment are warranted.

Association between Exposure to Particulate Matter during Pregnancy and Multidimensional Development in School-Age Children: A Cross-Sectional Study in Italy

Air pollutants can potentially affect the development of children. However, data on the effect of exposure to air pollution during pregnancy and developmental outcomes in school children are rare. We investigated the link between prenatal exposure to particulate matters smaller than 10 microns (PM₁₀) and the development of school-age children in multiple domains. Cross-sectional data were collected in Italy between 2013 and 2014. Children aged between 5 and 8 years (n = 1187) were assessed on cognitive, communication, socio-emotional, adaptive, and motor developmental domains using the Developmental Profile 3 questionnaire. The monthly average concentration of PM₁₀ during the entire fetal period was linked to the municipality of residence of the children. The increase in the prenatal PM₁₀ was associated with a decrease in the cognitive score during the second (+13.2 µg/m³ PM₁₀ increase: −0.30 points; 95%CI: −0.12–−0.48) and third trimesters of pregnancy (−0.31 points; 95%CI: −0.11–−0.50). The communicative domain was also negatively influenced by PM₁₀ increases in the second trimester. The development of cognitive and communicative abilities of children was negatively associated with the exposure to PM₁₀ during the period of fetal development, confirming that exposure to air pollution during pregnancy can potentially hinder the development of the brain.

Exposure of particulate matter (PM10) induces neurodevelopmental toxicity in zebrafish embryos

Particulate matter with 10 μm or less in diameter (PM₁₀) exposure is a major threat to health and environment around the world. Even though a number of clinical and experimental studies have focused on the cardiopulmonary effects of PM₁₀, its impact on neurovascular development and the underlying toxicity is relatively less studied. The present study is therefore undertaken to evaluate the potential toxic effects of PM₁₀ on neurodevelopment and the associated gene expression profiles in the zebrafish embryo/larvae. During 2017-2018, PM₁₀ samples (24 h sampling, 180 sampling days) were collected in an urban downtown site of Jinan, Shandong province, China. To delineate the potential toxic effects of PM₁₀ during neurodevelopment, zebrafish embryos/larvae were exposed to different concentrations viz., 25, 50, 100, 200, and 400 μg/mL of PM₁₀ solution for 24-120 h post-fertilization (hpf) and the effects on the mortality, morphology, swimming behavior, electroencephalogram discharges, growth of dopaminergic neurons, neurovasculature development and gene expression profiles of dopaminergic and neurodevelopment-related genes using qRT-PCR were studied. A significant increase in the mortality rate and morphological abnormalities were observed in 200 μg/mL of the PM₁₀ treated group at 120 hpf. High concentrations (≥100 μg/mL) of PM₁₀ exposure reduced locomotor behavior, caused abnormal electroencephalogram discharges, degeneration of dopaminergic neurons, inhibition of neurovascular development, cerebral hemorrhage, and significant changes in the expression pattern of genes involved in dopaminergic pathway and neurodevelopment such as (th1, dat, drd1, drd2a, drd3, drd4b, syn2a, gap43, α1-tubulin, gfap, map2, elavl3, eno2, neurog1, sox2, shha, and mbp). Taken together, all these parameters collectively imply developmental neurotoxicity and dysfunction of the dopaminergic neurons which provides the first evidence of PM₁₀-induced neurodevelopmental toxicity in the zebrafish embryo/larvae.

Non-nutritive suck and airborne metal exposures among Puerto Rican infants

Air pollution has been shown to impact multiple measures of neurodevelopment in young children. Its effects on particularly vulnerable populations, such as ethnic minorities, however, is less studied. To address this gap in the literature, we assess the associations between infant non-nutritive suck (NNS), an early indicator of central nervous system integrity, and air pollution exposures in Puerto Rico. Among infants aged 0-3 months enrolled in the Center for Research on Early Childhood Exposure and Development (CRECE) cohort from 2017 to 2019, we examined associations between exposure to fine particulate matter (PM_2.5) and its components on infant NNS in Puerto Rico. NNS was assessed using a pacifier attached to a pressure transducer, allowing for real-time visualization of NNS amplitude, frequency, duration, cycles/burst, cycles/min and bursts/min. These data were linked to 9-month average prenatal concentrations of PM_2.5 and components, measured at three community monitoring sites. We used linear regression to examine the PM_2.5-NNS association in single pollutant models, controlling for infant sex, maternal age, gestational age, and season of birth in base and additionally for household smoke exposure, age at testing, and NNS duration in full models. Among 198 infants, the average NNS amplitude and burst duration was 17.1 cmH₂O and 6.1 s, respectively. Decreased NNS amplitude was consistently and significantly associated with 9-month average exposure to sulfur (-1.026 ± 0.507), zinc (-1.091 ± 0.503), copper (-1.096 ± 0.535) vanadium (-1.157 ± 0.537), and nickel (-1.530 ± 0.501). Decrements in NNS frequency were associated with sulfur exposure (0.036 ± 0.018), but not other examined PM components. Our findings provide new evidence that prenatal maternal exposure to specific PM components are associated with impaired neurodevelopment in Puerto Rican infants soon after birth.

Air Pollution during Pregnancy and Childhood Autism Spectrum Disorder in Taiwan

Air pollutants have been linked to some diseases in humans, but their effects on the nervous system were less frequently evaluated. Autism spectrum disorder (ASD) is a group of neurondevelopmental disorders of which the etiology is still unknown. We conducted a study in Taiwan to evaluate the possible associations between prenatal exposure to air pollutants and ASD. From a random sample of one million people in the National Insurance Research Database, we identified all the infants born between 1996 and 2000. We followed them till the end of 2013 and identified cases of ASD. We traced back the mothers’ residence and assessed the exposure to air pollutants using the data obtained from the air quality monitoring database maintained by the government, which included ozone (O₃), carbon monoxide (CO), nitrogen dioxide (NO₂), sulfur dioxide (SO₂), and particulate matters with diameter less than 10 µm (PM₁₀). Cox proportional hazard models were constructed to evaluate the associations between childhood ASD and exposures to the pollutants in the three trimesters and the whole gestation. We identified a total of 63,376 newborns and included 62,919 as the study cohort. After adjusting for other risk factors, we observed trimester-specific associations between levels of CO, NO₂, and PM₁₀ and the risk of childhood ASD. An increase of 1 ppm of CO in the first, second, and third trimester was associated with a hazard ratio (HR) of 1.93 (95% confidence interval [CI]: 1.55–2.39), 1.77 (95%CI: 1.41–2.22), and 1.75 (95%CI: 1.39–2.21), respectively. An increase of 10 ppb in the level of NO₂ in the first, second, and third trimester was associated with an HR of 1.39 (95%CI: 1.22–1.58), 1.25 (95%CI: 1.10–1.42), and 1.18 (95%CI: 1.03–1.34), respectively. In conclusion, we found that exposures to CO and NO₂ in all three trimesters were associated with increased risks of developing ASD.

Preconceptional and the first trimester exposure to PM2.5 and offspring neurodevelopment at 24 months of age: Examining mediation by maternal thyroid hormones in a birth cohort study

Prenatal fine particulate matter (PM_2.5) exposure has been associated with impaired offspring neurodevelopment; however, the association of PM_2.5 exposure during preconception with offspring's neurodevelopment and factors responsible for this association are still unclear. This study estimated the associations of PM_2.5 exposure during preconception and the first trimester with offspring neurodevelopment and evaluated whether maternal thyroid hormones mediate these associations. We recruited 1329 mother-child pairs between 2013 and 2015 in Wuhan, China. PM_2.5 exposure levels of each woman during the 3 months preconception and the first trimester were estimated using land-use regression models. Offspring neurodevelopment characterized by mental developmental index (MDI) and psychomotor developmental index (PDI) were measured at 24 months of age. Maternal serum levels of free thyroxine (FT3), free triiodothyronine (FT4), and thyroid-stimulating hormone (TSH) during early pregnancy were measured of a subset of the 1329 women (551 women). Generalized estimation equation and general linear regression models were used to estimate the associations between maternal PM_2.5 exposure, thyroid hormones, and offspring neurodevelopment. After adjusting for potential confounders, we found that either among all participants or the subset, PM_2.5 exposure during preconception and the first trimester was negatively associated with offspring PDI. Double increment in the first trimester PM_2.5 exposure was significantly associated with 3.43 and 6.48 points decrease in offspring MDI. In the subset, each doubling of PM_2.5 exposure during preconception and the first trimester was significantly associated with 7.93 and 8.02 points decrease in maternal FT4 level, respectively. Increased maternal FT4, in turn, was associated with increased PDI (β = 16.69, 95% CI: 5.39, 27.99). About 7.7% (95% CI: 2.0%-19.4%) and 8.6% (95% CI: 3.0%, 22.1%) of the effect of PM_2.5 exposure during preconception on offspring PDI was mediated through maternal FT4 and the FT4/FT3 ratio, respectively.

Prenatal exposure to ambient fine particulate matter and early childhood neurodevelopment: A population-based birth cohort study

Although previous studies have reported the adverse effect of air pollution exposure during pregnancy on neurodevelopment in children, epidemiological evidence is limited, and the results are inconsistent. This study aimed to explore the association between prenatal ambient fine particulate matter (PM_2.5) exposure and early childhood neurodevelopment in a large birth cohort study of 4009 maternal-child pairs. Prenatal daily PM_2.5 exposure concentrations at 1 km spatial revolution were estimated using high-performance machine-learning models. Neurodevelopmental outcomes of children at ages 2, 6, 12, and 24 months were assessed using the Ages and Stages Questionnaire (ASQ). Distributed lag nonlinear models were used to identify critical windows of prenatal PM_2.5 exposure. General linear mixed models with binomially distributed errors were used to estimate the effect of prenatal PM_2.5 exposure on suspected developmental delay (SDD) in five developmental domains based on the longitudinal design. Prenatal PM_2.5 exposure was significantly associated with decreased scores for all neurodevelopmental domains of children at ages 2, 6, and 24 months. Each 10-μg/m³ increase in PM_2.5 exposure was significantly associated with increased risk of SDD for all subjects (RR: 1.52 95% CI: 1.19, 2.03), specifically, in problem-solving domain for girls (RR: 2.23, 95% CI: 1.22, 4.35). Prenatal PM_2.5 exposure in weeks 18 to 34 was significantly associated with both ASQ scores and SDDs. Our study proposed that prenatal PM_2.5 exposure affected early childhood neurodevelopment evaluated with the ASQ scale. PM_2.5 exposure might increase the risk of SDD for boys and girls, specifically in the problem-solving domain for girls.

Effects of air pollution, land-use type, and maternal mental health on child development in the first two years of life in the Greater Taipei area

INTRODUCTION

Few studies have investigated the associations of child development with air pollution, land-use type, and maternal mental health simultaneously. Therefore, we evaluated the effect of exposure to air pollutants during several critical periods of life, with adjustment for land-use type and maternal mental status, on child development at 6, 12, and 24 months of age in the Greater Taipei area.

METHODS

Participants were selected from an ongoing Taiwanese birth cohort study. We analyzed the data of the participants who had been recruited from January 2011 to April 2014. Self-administered standardized questionnaires were used to collect information on sociodemographic factors, infant development and health, maternal mental status, etc. Air pollution levels in pre- and postnatal periods were estimated using a spatial interpolation technique (ordinary kriging) at children's residential addresses. Land-use types around participants' homes were evaluated using buffer analysis. We used multiple logistic regression analysis to examine the relationships between child development delay and environmental factors.

RESULTS

In total, 228, 361, and 441 families completed child development forms at 6, 12, and 24 months of age, respectively. Our results indicated that prenatal exposure to particulate matter with aerodynamic diameter ≤10 μm and O₃ and postnatal exposure to NO₂ were negatively associated with child development. Traffic-related land-use types, gas stations, and power generation areas around participants' homes were also adversely correlated with child development. Moreover, poor maternal mental health was associated with child development delay.

CONCLUSION

Prenatal exposure and postnatal exposure to air pollution were associated with development delay in children under 2 years of age, specifically those under 1 year of age, even after adjustment for land-use type and maternal mental status. Living environment is critical for the development of children under 2 years of age.

Prenatal air pollution exposure and neurodevelopment: A review and blueprint for a harmonized approach within ECHO

BACKGROUND

Air pollution exposure is ubiquitous with demonstrated effects on morbidity and mortality. A growing literature suggests that prenatal air pollution exposure impacts neurodevelopment. We posit that the Environmental influences on Child Health Outcomes (ECHO) program will provide unique opportunities to fill critical knowledge gaps given the wide spatial and temporal variability of ECHO participants.

OBJECTIVES

We briefly describe current methods for air pollution exposure assessment, summarize existing studies of air pollution and neurodevelopment, and synthesize this information as a basis for recommendations, or a blueprint, for evaluating air pollution effects on neurodevelopmental outcomes in ECHO.

METHODS

We review peer-reviewed literature on prenatal air pollution exposure and neurodevelopmental outcomes, including autism spectrum disorder, attention deficit hyperactivity disorder, intelligence, general cognition, mood, and imaging measures. ECHO meta-data were compiled and evaluated to assess frequency of neurodevelopmental assessments and prenatal and infancy residential address locations. Cohort recruitment locations and enrollment years were summarized to examine potential spatial and temporal variation present in ECHO.

DISCUSSION

While the literature provides compelling evidence that prenatal air pollution affects neurodevelopment, limitations in spatial and temporal exposure variation exist for current published studies. As >90% of the ECHO cohorts have collected a prenatal or infancy address, application of advanced geographic information systems-based models for common air pollutant exposures may be ideal to address limitations of published research.

CONCLUSIONS

In ECHO we have the opportunity to pioneer unifying exposure assessment and evaluate effects across multiple periods of development and neurodevelopmental outcomes, setting the standard for evaluation of prenatal air pollution exposures with the goal of improving children's health.

Review of epidemiological studies on air pollution and health effects in children

There is a growing body of literature on the adverse health effects of ambient air pollution. Children are more adversely affected by air pollution due to their biological susceptibility and exposure patterns. This review summarized the accumulated epidemiologic evidence with emphasis on studies conducted in Korea and heterogeneity in the literature. Based on systematic reviews and meta-analyses, there is consistent evidence on the association between exposure to ambient air pollution and children's health, especially respiratory health and adverse birth outcomes, and growing evidence on neurodevelopmental outcomes. Despite these existing studies, the mechanism of the adverse health effects of air pollution and the critical window of susceptibility remain unclear. There is also a need to identify causes of heterogeneity between studies in terms of measurement of exposure/outcome, study design, and the differential characteristics of air pollutants and population.

Inflammatory effects of particulate matter air pollution

Air pollution is an important cause of non-communicable diseases globally with particulate matter (PM) as one of the main air pollutants. PM is composed of microscopic particles that contain a mixture of chemicals and biological elements that can be harmful to human health. The aerodynamic diameter of PM facilitates their deposition when inhaled. For instance, coarse PM having a diameter of < 10 μm is deposited mainly in the large conducting airways, but PM of < 2.5 μm can cross the alveolar-capillary barrier, traveling to other organs within the body. Epidemiological studies have shown the association between PM exposure and risk of disease, namely those of the respiratory system such as lung cancer, asthma, and chronic obstructive pulmonary disease (COPD). However, cardiovascular and neurological diseases have also been reported, including hypertension, atherosclerosis, acute myocardial infarction, stroke, loss of cognitive function, anxiety, and Parkinson's and Alzheimer's diseases. Inflammation is a common hallmark in the pathogenesis of many of these diseases associated with exposure to a variety of air pollutants, including PM. This review focuses on the main effects of PM on human health, with an emphasis on the role of inflammation.

The Relationship Between Air Pollution and Cognitive Functions in Children and Adolescents: A Systematic Review

Air pollution has a negative impact on one's health and on the central nervous system. We decided to assess studies that evaluated the relationship between air pollution and cognitive functions in children and adolescents by reviewing studies that had been published between January 2009 and May 2019. We searched three major databases for original works (26 studies) and for studies using brain imaging methods based on MRI (six studies). Adverse effects of air pollutants on selected cognitive or psychomotor functions were found in all of the studies. Exposure to nitrogen dioxide, for example, was linked to impaired working memory, general cognitive functions, and psychomotor functions; particulate matter 2.5 was linked to difficulties in working memory, short-term memory, attention, processing speed, and fine motor function; black carbon was linked to poor verbal intelligence, nonverbal intelligence, and working memory; airborne copper was linked to impaired attentiveness and fine motor skills; isophorone was linked to lower mathematical skills; and polycyclic aromatic hydrocarbons in fetal life were linked to lower intelligence scores. The studies using MRI showed that high concentrations of air pollutants were linked to changes in the brain's white matter or lower functional integration and segregation in children's brain networks. In view of the global increase in air pollution, there is a need for further research to elucidate the relationship between air pollution and cognitive and motor development in children. According to some studies, neuroinflammation, the e4 allele of the apolipoprotein E gene, and gutathione-S-transferase gene polymorphism processes may play a role.

Identifying critical exposure windows for ambient air pollution and semen quality in Chinese men

Emerging studies documented the association between ambient air pollution exposure and semen quality, but the critical exposure windows have not been comprehensively studied. To identify susceptible windows for associations of exposure to ambient respirable particulate matter (PM₁₀), nitrogen dioxide (NO₂), sulfur dioxide (SO₂), and ozone (O₃) with sperm concentration, sperm count, total motility, and progressive motility, we recruited 1061 men attending an infertility clinic in Wuhan, China, between 2011 and 2013. We used a distributed lag multivariate linear regression to assess the exposure-lag-response relationship between semen quality and weekly air pollution exposure. The critical exposure windows were during the 6th to 12th sperm development weeks for PM₁₀, 10th to 11th weeks for O₃, and 0 to 5th weeks for SO₂. Over the entire 12 weeks of spermatogenesis period, an interquartile range increase (IQR) increase in PM₁₀ was associated with declined sperm concentration [-45.64% (95% CI: -59.97%, -26.18%) percent decrease], declined sperm count [-49.42% (95% CI: -64.42%, -28.09%) percent decrease], reduced total motility [-12.42 (95% CI: -20.47, -4.37)], and reduced progressive motility [-8.81 (95% CI: -16.00, -1.61)], SO₂ per IQR increase was associated with reduced sperm concentration [-39.73% (95% CI: -55.96%, -17.51%) percent decrease] and total motility [-8.64 (95% CI: -16.90, -0.38)], but NO₂ and O₃ were not associated with any of the four sperm quality parameters. Our findings suggest that exposure to PM₁₀ during spermatidogenesis period, exposure to SO₂ during spermatocytogenesis period, and exposure to O₃ during spermiogenesis period were associated with impaired semen quality, which implies air pollutants impair semen quality through varied pathways.

Effects of prenatal exposure to NO2 on children's neurodevelopment: a systematic review and meta-analysis

The neurotoxicity of NO₂ exposure is well-known and potentially causes impaired of neural functions. This review aimed to estimate associations between prenatal NO₂ exposure and neurodevelopment for children. Articles published until May 2019 reported prenatal NO₂ exposure and children's cognition, psychomotor, language, attention, IQ, and behavior function were searched according to all related terms. The main databases we retrieved included PubMed, Web of Science, Embase, and Cochrane Library. Coefficient was extracted, conversed, and synthesized by random effects meta-analysis. Meanwhile, qualitatively describe would be used for some studies which cannot be synthesized quantitatively for lack of quantity or methods inconsistency. Finally, a total of 3848 citations were searched, and only 10 studies were included. We estimated that per 10 μg/m³ increase of NO₂ during pregnancy was associated with a - 0.76 point decrease in global psychomotor (95% CI, - 1.34, - 0.18) and a - 0.62 point decrease in fine psychomotor for children (95% CI, - 1.09, - 0.16). But no significant association found in general cognitive and language. In addition, through the literature review, it seemed that prenatal exposure to NO₂ might cause adverse impacts on children's attention, IQ, and different behaviors, but this requires confirmation from further researches. Our study indicated that prenatal exposure to NO₂ seems to be associated with impaired neural development for children, especially for fine psychomotor. However, further studies are needed for determining the effects of prenatal air pollution exposure on attention, IQ, and behavior.

Effects of early life exposure to traffic-related air pollution on brain development in juvenile Sprague-Dawley rats

Epidemiological studies link traffic-related air pollution (TRAP) to increased risk for various neurodevelopmental disorders (NDDs); however, there are limited preclinical data demonstrating a causal relationship between TRAP and adverse neurodevelopmental outcomes. Moreover, much of the preclinical literature reports effects of concentrated ambient particles or diesel exhaust that do not recapitulate the complexity of real-world TRAP exposures. To assess the developmental neurotoxicity of more realistic TRAP exposures, we exposed male and female rats during gestation and early postnatal development to TRAP drawn directly from a traffic tunnel in Northern California and delivered to animals in real-time. We compared NDD-relevant neuropathological outcomes at postnatal days 51-55 in TRAP-exposed animals versus control subjects exposed to filtered air. As indicated by immunohistochemical analyses, TRAP significantly increased microglial infiltration in the CA1 hippocampus, but decreased astrogliosis in the dentate gyrus. TRAP exposure had no persistent effect on pro-inflammatory cytokine levels in the male or female brain, but did significantly elevate the anti-inflammatory cytokine IL-10 in females. In male rats, TRAP significantly increased hippocampal neurogenesis, while in females, TRAP increased granule cell layer width. TRAP had no effect on apoptosis in either sex. Magnetic resonance imaging revealed that TRAP-exposed females, but not males, also exhibited decreased lateral ventricular volume, which was correlated with increased granule cell layer width in the hippocampus in females. Collectively, these data indicate that exposure to real-world levels of TRAP during gestation and early postnatal development modulate neurodevelopment, corroborating epidemiological evidence of an association between TRAP exposure and increased risk of NDDs.