Exposure to coarse particulate matter during gestation and term low birthweight in California: Variation in exposure and risk across region and socioeconomic subgroup

An Ensemble Machine Learning Model to Enhance Extrapolation Ability of Predicting Coarse Particulate Matter with High Resolutions in China

Accurate exposure assessment is important for conducting PM10-2.5-related epidemiological studies, which have been limited thus far. In this study, we aimed to develop an ensemble machine learning method to estimate PM10-2.5 concentrations in mainland China during 2013-2020. The study was conducted in two stages. In the first stage, we developed two methods: the indirect method refers to developing models for PM2.5 and PM10 separately and subsequently calculating PM10-2.5 as the difference between them; and the direct method refers to establishing a model between PM10-2.5 measurements and relevant predictors directly. In the second stage, we employed an ensemble method by integrating predictions from both indirect and direct methods. Internal and external cross-validation (CV) were performed to validate the extrapolation capacity of models. The ensemble method demonstrated enhanced extrapolation accuracy in both internal and external CV compared to indirect and direct methods. The predictions produced by the ensemble method captured the spatiotemporal pattern of PM10-2.5, even in the sand and dust storm seasons. Our study introduces an ensemble strategy leveraging the strengths of both indirect and direct methods to estimate PM10-2.5 concentrations, which holds significant potential to support future epidemiological studies to address knowledge gaps in understanding the health effects of PM10-2.5.

Does Exposure to Ambient Air Pollution Affect Gestational Age and Newborn Weight?-A Systematic Review

Current evidence suggests that airborne pollutants have a detrimental effect on fetal growth through the emergence of small for gestational age (SGA) or term low birth weight (TLBW). The study's objective was to critically evaluate the available literature on the association between environmental pollution and the incidence of SGA or TLBW occurrence. A comprehensive literature search was conducted across Pubmed/MEDLINE, Web of Science, Cochrane Library, EMBASE, and Google Scholar using predefined inclusion and exclusion criteria. The methodology adhered to the PRISMA guidelines. The systematic review protocol was registered in PROSPERO with ID number: CRD42022329624. As a result, 69 selected papers described the influence of environmental pollutants on SGA and TLBW occurrence with an Odds Ratios (ORs) of 1.138 for particulate matter ≤ 10 μm (PM10), 1.338 for particulate matter ≤ 2.5 μm (PM2.5), 1.173 for ozone (O3), 1.287 for sulfur dioxide (SO2), and 1.226 for carbon monoxide (CO). All eight studies analyzed validated that exposure to volatile organic compounds (VOCs) is a risk factor for SGA or TLBW. Pregnant women in the high-risk group of SGA occurrence, i.e., those living in urban areas or close to sources of pollution, are at an increased risk of complications. Understanding the exact exposure time of pregnant women could help improve prenatal care and timely intervention for fetuses with SGA. Nevertheless, the pervasive air pollution underscored in our findings suggests a pressing need for adaptive measures in everyday life to mitigate worldwide environmental pollution.

Influence of gestational hypertension and maternal air pollutant exposure on birth outcomes

The relationship between exposure to air pollutants and fetal growth outcomes has shown inconsistency, and only a limited number of studies have explored the impact of air pollution on gestational hypertension and birth outcomes. This study aimed to evaluate how maternal exposure to air pollutants and blood pressure could influence fetal birth outcomes. A total of 55 women with gestational hypertension and 131 healthy pregnant women were enrolled in this study. Data pertaining to personal characteristics, prenatal examinations, outdoor air pollutant exposure, and fetal birth outcomes were collected. The study revealed that fetal birth weight and abdominal circumference exhibited a significant reduction among women with gestational hypertension compared to healthy pregnant women, even after adjustments for body mass index, gestational age, and exposure to air pollutants had been made. Moreover, maternal exposure to outdoor air pollutants displayed a notable correlation with decreased birth length of fetuses. Consequently, the study concluded that maternal blood pressure and exposure to outdoor air pollutants during pregnancy potentially stand as pivotal factors influencing fetal birth outcomes.

Prenatal exposure to air pollutant mixtures and birthweight in the upstate KIDS cohort

BACKGROUND

Single-pollutant models have linked prenatal PM2.5 exposure to lower birthweight. However, analyzing air pollutant mixtures better captures pollutant interactions and total effects. Unfortunately, strong correlations between pollutants restrict traditional methods.

OBJECTIVES

We explored the association between exposure to a mixture of air pollutants during different gestational age windows of pregnancy and birthweight.

METHODS

We included 4,635 mother-infant dyads from a New York State birth cohort born 2008-2010. Air pollution data were sourced from the EPA's Community Multiscale Air Quality model and matched to the census tract centroid of each maternal home address. Birthweight and gestational age were extracted from vital records. We applied linear regression to study the association between prenatal exposure to PM2.5, PM10, NOX, SO2, and CO and birthweight during six sensitive windows. We then utilized Bayesian kernel machine regression to examine the non-linear effects and interactions within this five-pollutant mixture. Final models adjusted for maternal socio-demographics, infant characteristics, and seasonality.

RESULTS

Single-pollutant linear regression models indicated that most pollutants were associated with a decrement in birthweight, specifically during the two-week window before birth. An interquartile range increase in PM2.5 exposure (IQR: 3.3 µg/m3) from the median during this window correlated with a 34 g decrement in birthweight (95 % CI: -54, -14), followed by SO2 (IQR: 2.0 ppb; β: -31), PM10 (IQR: 4.6 µg/m3; β: -29), CO (IQR: 60.8 ppb; β: -27), and NOX (IQR: 7.9 ppb; β: -26). Multi-pollutant BKMR models revealed that PM2.5, NOX, and CO exposure were negatively and non-linearly linked with birthweight. As the five-pollutant mixture increased, birthweight decreased until the median level of exposure.

DISCUSSION

Prenatal exposure to air pollutants, notably PM2.5, during the final two weeks of pregnancy may negatively impact birthweight. The non-linear relationships between air pollution and birthweight highlight the importance of studying pollutant mixtures and their interactions.

Neonatal outcomes in preterm infants with severe congenital heart disease: a national cohort analysis

Background

Prematurity and congenital heart disease (CHD) are the leading causes of neonatal mortality and morbidity. Limited data are available about the outcomes of premature infants with severe CHD.

Methods

We queried The National Inpatient Database using ICD-10 codes for premature patients (<37 weeks) with severe CHD from 2016 to 2020. Severe CHDs were grouped into three categories: A. left-sided lesions with impaired systemic output, B. Cyanotic CHD, and C. Shunt lesions with pulmonary overcirculation. Patients with isolated atrial or ventricular septal defects and patent ductus arteriosus were excluded. We also excluded patients with chromosomal abnormalities and major congenital anomalies. Patients' demographics, clinical characteristics, and outcomes were evaluated by comparing premature infants with vs. without CHD adjusting for gestational age (GA), birth weight, and gender.

Results

A total of 27710 (1.5%) out of 1,798,245 premature infants had severe CHD. This included 27%, 58%, and 15% in groups A, B, and C respectively. The incidence of severe CHD was highest between 25 and 28 weeks of gestation and decreased significantly with increasing GA up to 36 weeks (p < 0.001). Premature infants with severe CHD had a significantly higher incidence of neonatal morbidities including necrotizing enterocolitis (NEC) [OR = 4.88 (4.51-5.27)], interventricular hemorrhage [OR = 6.22 (5.57-6.95)], periventricular leukomalacia [OR = 3.21 (2.84-3.64)] and bronchopulmonary dysplasia [OR = 8.26 (7.50-10.06) compared to preterm infants of similar GA without CHD. Shunt lesions had the highest incidence of NEC (8.5%) compared to 5.3% in cyanotic CHD and 3.7% in left-sided lesions (p < 0.001). Mortality was significantly higher in premature infants with CHD compared to control [11.6% vs. 2.5%, p < 0.001]. Shunt lesions had significantly higher mortality (11.0%) compared to those with left-sided lesions (8.3%) and cyanotic CHD (6.4%), p < 0.001.

Conclusion

Premature infants with severe CHD are at high risk of neonatal morbidity and mortality. Morbidity remains increased across all GA groups and in all CHD categories. This significant risk of adverse outcomes is important to acknowledge when managing this patient population and when counseling their families. Future research is needed to examine the impact of specific rather than categorized congenital heart defects on neonatal outcomes.

Methods in Public Health Environmental Justice Research: a Scoping Review from 2018 to 2021

PURPOSE OF REVIEW

The volume of public health environmental justice (EJ) research produced by academic institutions increased through 2022. However, the methods used for evaluating EJ in exposure science and epidemiologic studies have not been catalogued. Here, we completed a scoping review of EJ studies published in 19 environmental science and epidemiologic journals from 2018 to 2021 to summarize research types, frameworks, and methods.

RECENT FINDINGS

We identified 402 articles that included populations with health disparities as a part of EJ research question and met other inclusion criteria. Most studies (60%) evaluated EJ questions related to socioeconomic status (SES) or race/ethnicity. EJ studies took place in 69 countries, led by the US (n = 246 [61%]). Only 50% of studies explicitly described a theoretical EJ framework in the background, methods, or discussion and just 10% explicitly stated a framework in all three sections. Among exposure studies, the most common area-level exposure was air pollution (40%), whereas chemicals predominated personal exposure studies (35%). Overall, the most common method used for exposure-only EJ analyses was main effect regression modeling (50%); for epidemiologic studies the most common method was effect modification (58%), where an analysis evaluated a health disparity variable as an effect modifier. Based on the results of this scoping review, current methods in public health EJ studies could be bolstered by integrating expertise from other fields (e.g., sociology), conducting community-based participatory research and intervention studies, and using more rigorous, theory-based, and solution-oriented statistical research methods.

Health risk assessment for particulate matter: application of AirQ+ model in the northern Caribbean region of Colombia

Air pollution is considered the world's most important environmental and public health risk. The annual exposure for particulate matter (PM) in the northern Caribbean region of Colombia between 2011 and 2019 was determined using PM records from 25 monitoring stations located within the area. The impact of exposure to particulate matter was assessed through the updated Global Burden of Disease health risk functions using the AirQ+ model for mortality attributable to acute lower respiratory disease (in children ≤ 4 years); mortality in adults aged > 18 years old attributable to chronic obstructive pulmonary disease, ischaemic heart disease, lung cancer, and stroke; and all-cause post-neonatal infant mortality. The proportions of the prevalence of bronchitis in children and the incidence of chronic bronchitis in adults attributable to PM exposure were also estimated for the population at risk. Weather Research and Forecasting-California PUFF (WRF-CALPUFF) modeling systems were used to estimate the spatiotemporal trends and calculate mortality relative risk due to prolonged PM2.5 exposure. Proportions of mortality attributable to long-term exposure to PM2.5 were estimated to be around 11.6% of ALRI deaths in children ≤ 4 years of age, 16.1% for COPD, and 26.6% for IHD in adults. For LC and stroke, annual proportions attributable to PM exposure were estimated to be 9.1% and 18.9%, respectively. An estimated 738 deaths per year are directly attributed to particulate matter pollution. The highest number of deaths per year is recorded in the adult population over 18 years old with a mean of 401 events. The mean risk in terms of the prevalence of bronchitis attributable to air pollution in children was determined to be 109 per 100,000 inhabitants per year. The maximum RR values for mortality (up 1.95%) from long-term PM2.5 exposure were predicted to correspond to regions downwind to the industrial zone.

Supplementary information

The online version contains supplementary material available at 10.1007/s11869-023-01304-5.

Risks of preterm birth and low birth weight and maternal exposure to NO2/PM2.5 acquired by dichotomous evaluation: a systematic review and meta-analysis

No consistent results from past studies have been found on the relationship between the effects of air pollutant exposure, preterm birth (PTB) and low birth weight (LBW) in fetuses. This study aimed to analyze the impact of high concentrations of air pollutants on the health outcomes of fetuses, especially regarding PTB and LBW. This study used keywords related to air pollutants, pregnancy, and birth outcomes, to search the literature within the databases of the Cochrane Library, PubMed, and Embase, which were published as of July 26, 2022. A total of 24 studies were included in this meta-analysis. This meta-analysis revealed that nitrogen dioxide (NO₂) exposure throughout pregnancy was associated with an increased risk of PTB. Maternal exposure to PM_2.5 (particulate matter sized less than 2.5 μm) during gestation was associated with the risk of LBW. The findings of this meta-analysis provide an important foundation for evaluating the relationship between exposure of air pollutants and fetal birth outcomes in countries with severe air pollution in the future.

Association Between Ambient Air Pollution and Birth Weight by Maternal Individual- and Neighborhood-Level Stressors

IMPORTANCE

Fetal growth is precisely programmed and could be interrupted by environmental exposures during specific times during pregnancy. Insights on potential sensitive windows of air pollution exposure in association with birth weight are needed.

OBJECTIVE

To examine the association of sensitive windows of ambient air pollution exposure with birth weight and heterogeneity by individual- and neighborhood-level stressors.

DESIGN, SETTING, AND PARTICIPANTS

Data on a cohort of low-income Hispanic women with singleton term pregnancy were collected from 2015 to 2021 in the ongoing Maternal and Developmental Risks from Environmental and Social Stressors cohort in Los Angeles, California.

EXPOSURES

Daily ambient particulate matter with aerodynamic diameter less than 10 μm (PM10) and aerodynamic diameter less than 2.5 μm (PM2.5), nitrogen dioxide (NO2), and 8-hour maximum ozone were assigned to residential locations. Weekly averages from 12 weeks before conception to 36 gestational weeks were calculated. Individual-level psychological stressor was measured by the Perceived Stress Scale. Neighborhood-level stressor was measured by the CalEnviroScreen 4.0.

MAIN OUTCOMES AND MEASURES

Sex-specific birth weight for gestational age z score (BWZ). The associations between air pollutant and BWZ were estimated using distributed lag models to identify sensitive windows of exposure, adjusting for maternal and meteorologic factors. We stratified the analyses by Perceived Stress Scale and CalEnviroScreen 4.0. We converted the effect size estimation in BWZ to grams to facilitate interpretation.

RESULTS

The study included 628 pregnant women (mean [SD] age, 22.18 [5.92] years) and their newborns (mean [SD] BWZ, -0.08 [1.03]). On average, an interquartile range (IQR) increase in PM2.5 exposure during 4 to 22 gestational weeks was associated with a -9.5 g (95% CI, -10.4 to -8.6 g) change in birth weight. In stratified models, PM2.5 from 4 to 24 gestational weeks was associated with a -34.0 g (95% CI, -35.7 to -32.4 g) change in birth weight and PM10 from 9 to 14 gestational weeks was associated with a -39.4 g (95% CI, -45.4 to -33.4) change in birth weight in the subgroup with high Perceived Stress Scale and high CalEnviroScreen 4.0 scores. In this same group, NO2 from 9 to 14 gestational weeks was associated with a -40.4 g (95% CI, -47.4 to -33.3 g) change in birth weight and, from 33 to 36 gestational weeks, a -117.6 g (95% CI, -125.3 to -83.7 g) change in birth weight. Generally, there were no significant preconception windows for any air pollutants or ozone exposure with birth weight.

CONCLUSIONS AND RELEVANCE

In this cohort study, early pregnancy to midpregnancy exposures to PM2.5, PM10, and NO2 were associated with lower birth weight, particularly for mothers experiencing higher perceived stress and living in a neighborhood with a high level of stressors from environmental pollution.

Both parents matter: a national-scale analysis of parental race/ethnicity, disparities in prenatal PM2.5 exposures and related impacts on birth outcomes

BACKGROUND

Most U.S. studies that report racial/ethnic disparities in increased risk of low birth weight associated with air pollution exposures have been conducted in California or northeastern states and/or urban areas, limiting generalizability of study results. Few of these studies have examined maternal racial/ethnic groups other than Non-Hispanic Black, non-Hispanic White and Hispanic, nor have they included paternal race. We aimed to examine the independent effects of PM_2.5 on birth weight among a nationally representative sample of U.S. singleton infants and how both maternal and paternal race/ethnicity modify relationships between prenatal PM_2.5 exposures and birth outcomes.

METHODS

We used data from the Early Childhood Longitudinal Study, Birth Cohort (ECLS-B), a longitudinal nationally representative cohort of 10,700 U.S. children born in 2001, which we linked to U.S.EPA's Community Multi-scale Air Quality (CMAQ)-derived predicted daily PM2.5 concentrations at the centroid of each Census Bureau Zip Code Tabulation Area (ZCTA) for maternal residences. We examined relationships between term birthweight (TBW)_, term low birthweight rate (TLBW) and gestational PM_2.5 pollutant using multivariate regression models. Effect modification of air pollution exposures on birth outcomes by maternal and paternal race was evaluated using stratified models. All analyses were conducted with sample weights to provide national-scale estimates.

RESULTS

The majority of mothers were White (61%). Fourteen percent of mothers identified as Black, 21% as Hispanic, 3% Asian American and Pacific Islander (AAPI) and 1% American Indian and Alaskan Native (AIAN). Fathers were also racially/ethnically diverse with 55% identified as White Non-Hispanic, 10% as Black Non-Hispanic, 19% as Hispanic, 3% as AAPI and 1% as AIAN. Results from the chi-square and ANOVA tests of significance for racial/ethnic differences indicate disparities in prenatal exposures and birth outcomes by both maternal and paternal race/ethnicity. Prenatal PM_2.5 was associated with reduced birthweights during second and third trimester and over the entire gestational period in adjusted regression models, although results did not reach statistical significance. In models stratified by maternal race and paternal race, one unit increase in PM_2.5 was statistically significantly associated with lower birthweights among AAPI mothers, -5.6 g (95% CI:-10.3, -1.0 g) and AAPI fathers, -7.6 g (95% CI: -13.1, -2.1 g) during 3^rd trimester and among births where father's race was not reported, -14.2 g (95% CI: -24.0, -4.4 g).

CONCLUSIONS

These data suggest that paternal characteristics should be used, in addition to maternal characteristics, to describe the risks of adverse birth outcomes. Additionally, our study suggests that serious consideration should be given to investigating environmental and social mechanisms, such as air pollution exposures, as potential contributors to disparities in birth outcomes among AAPI populations.

A Co-Twin control study of fine particulate matter and the prevalence of metabolic syndrome risk factors

The relationship between ambient fine particulate matter (PM_2.5) and metabolic syndrome (MetS) is understudied. It also remains unknown whether familial factors play a role in this relationship. In a study of 566 middle-aged twins, we examined the association of PM_2.5 with MetS risk factors, measured by a MetS score as a summation of individual risk factors (range, 0 to 5). High-resolution PM_2.5 estimates were obtained through previously validated models that incorporated monitor and satellite derived data. We estimated two-year average PM_2.5 concentrations based on the ZIP code of each twin's residence. We used ordinal response models adapted for twin studies. When treating twins as individuals, the odds ratio of having 1-point higher MetS score was 1.78 for each 10 μg/m³-increase in exposure to PM_2.5 (confidence interval [CI]: 1.01, 3.15), after adjusting for potential confounders. This association was mainly between pairs; the odds ratio was 1.97 (CI: 1.01, 3.84) for each 10 μg/m³-increase in the average pairwise exposure level. We found no significant difference in MetS scores within pairs who were discordant for PM_2.5 exposure. In conclusion, higher PM_2.5 in residence area is associated with more MetS risk factors. This association, however, is confounded by shared familial factors.

Impact of Maternal Demographic and Socioeconomic Factors on the Association Between Particulate Matter and Adverse Birth Outcomes: a Systematic Review and Meta-analysis

BACKGROUND

Numerous studies conducted in the United States found associations between prenatal exposure to particulate matter (PM) and adverse birth outcomes, and some studies identified vulnerable populations, including certain racial/ethnic groups and people with low-socioeconomic status. However, their findings are not always consistent. In this review, we compared the risk of adverse birth outcomes due to PM exposures among subpopulations and investigated whether any particular population is more vulnerable.

METHODS

We selected U.S. studies examining associations between PM exposure during pregnancy and birth outcomes that included results for effect modification by race/ethnicity and/or maternal education. We summarized the findings for various sizes of PM and birth outcomes. Meta-analysis was conducted to quantify vulnerable race/ethnicity for the association between fine PM (PM_2.5) and birthweight.

RESULTS

In total, 19 studies were assessed, and PM-related risks of adverse birth outcomes, particularly those related to fetal growth, likely differ across subpopulations. A meta-analysis from five studies showed that a 10 μg/m³ increase of PM_2.5 during the full-gestation reduced birthweight by 21.9 g (95% confidence interval 11.7, 32.0), 15.7 g (10.1, 21.4), 9.3 g (2.7, 15.8), and 5.8 g (- 9.0, 20.7) for Black, White, Hispanic, and Asian mothers, respectively.

CONCLUSION

Our review indicated that Black mothers and mothers with low educational attainment are more vulnerable subpopulations. More investigation is needed for effect modification by other maternal factors, such as household income. Characterizing and quantifying vulnerable subpopulations are essential for addressing environmental justice since it can help regulatory agencies allocate resources and design policy interventions.

Can the New Subway Line Openings Mitigate PM10 Concentration? Evidence from Chinese Cities Based on the PSM-DID Method

The large-scale construction of subway systems, which is viewed as one of the potential measures to mitigate traffic congestion and its resulting air pollution and health impact, is taking place in major cities throughout China. However, the literature on the impact of the new subway line openings on particulate matter with a diameter less than 10 µm (PM10) at the city level is scarce. Employing the Propensity Score Matching-Difference-in-differences method, this paper examines the effect of the new subway line openings on air quality in terms of PM10 in China, using the daily PM10 concentration data from January 2014 to Dececember 2017. Our finding shows that the short-term treatment effect on PM10 is more controversial. Furthermore, for different time windows, the result confirms an increase in PM10 pollution during the short term, while the subway line openings improve air quality in the longer term. In addition, we find that the treatment effect results in high PM10 pollution for cities with 1-2 million people, while it improves air quality for cities with over 2 million people. Moreover, for cities with varying levels of GDP, there is evidence of a reduction in PM10 after the subway line openings. Mechanism analysis supports the conclusion that the PM10 reduction originated from substituting the subway for driving.

The Association Between Air Pollution and Low Birth Weight and Preterm Labor in Ahvaz, Iran

PURPOSE

Pregnant women and fetuses are sensitive to air pollution due to physiological changes in pregnancy. The aim of this study was to determine the relationship between exposure to air pollution, low birth weight and preterm labor in Ahvaz.

METHODS

This research was a time-series study. The research sample consisted of all data about low birth weight and preterm labor pregnant women from Imam Khomeini Hospital and Razi Hospital in Ahvaz city. Air pollutant data including O3, NO, NO2, SO2, CO, PM10 and PM2.5 and climate data were collected from the Environmental Protection Agency and the Khuzestan Province during a 10-year period from 2008 to 2018. The generalized additive models (GAMs) with different air pollutant lags up to 6 days were used.

RESULTS

The results of multiple GAM model have shown that there is a direct and significant relationship between exposure to PM10 at 0-6-day lag, SO2 at 2- and 3-day lag and low birth weight. In addition, there was a direct and significant correlation between exposure to NO2, NO, CO and PM2.5 at 0-6-day lag and preterm labor.

CONCLUSION

The results indicate the effect of air pollutants on low birth weight and preterm labor. Therefore, pregnant women should be informed about the negative consequences of air pollution and avoid exposure to polluted air during pregnancy.

Environmental and Socioeconomic Factors Influence the Live-Born Incidence of Congenital Heart Disease: A Population-Based Study in California

BACKGROUND

The development of congenital heart disease (CHD) is multifactorial with genetic and environmental influences. We sought to determine the relationship between socioeconomic and environmental factors with the incidence of CHD among live‐born infants in California and to determine whether maternal comorbidities are in the causal pathway.

METHODS AND RESULTS

This was a population‐based cohort study in California (2007–2012). The primary outcome was having significant CHD. Predictors included socioeconomic status and environmental exposure to pollutants determined by U.S. Census data. A social deprivation index and environmental exposure index was assigned based on neighborhood socioeconomic variables, categorized into 4 quartiles. Quartile 1 was the best with the least exposure to pollutants and social deprivation, and quartile 4 was the worst. Multivariate logistic regression and mediation analyses were performed. Among 2 419 651 live‐born infants, the incidence of CHD was 3.2 per 1000 live births. The incidence of CHD was significantly higher among those in quartile 4 compared with quartile 1 (social deprivation index: 0.35% versus 0.29%; odds ratio [OR], 1.31; 95% CI, 1.21–1.41; environmental exposure index: 0.35% versus 0.29%; OR, 1.23; 95% CI, 1.15–1.31) after adjusting for maternal race/ethnicity and age and accounting for the relationship between the 2 primary predictors. Maternal comorbidities explained 13% (95% CI, 10%–20%) of the relationship between social deprivation index and environmental exposure index with the incidence of CHD.

CONCLUSIONS

Increased social deprivation and exposure to environmental pollutants are associated with the incidence of live‐born CHD in California. Maternal comorbidities explain some, but not all, of this relationship. These findings identify targets for social policy initiatives to minimize health disparities.

The associations of particulate matters with fetal growth in utero and birth weight: A birth cohort study in Beijing, China

BACKGROUND

Previous studies examined the associations of particulate matters (PM) with fetal growth in utero or birth weight with inconsistent results, and few studies investigated that whether the associations of PM with fetal growth in utero also present at birth. We aimed to investigate the associations of PM with both fetal growth in utero and birth weight.

METHODS

We established a birth cohort (2014-2017) with 18,863 singleton pregnancies in Tongzhou Maternal and Child Hospital of Beijing, China. Maternal exposure to PM with aerodynamic diameters ≤2.5 μm and ≤ 10 μm (PM_2.5/PM₁₀) during pregnancy was estimated using the inverse distance weighting method. Estimated birth weight (EFW) was assessed by ultrasound measurements and birth weight was measured at birth, which were both standardized as gestational-age- and gender-adjusted Z-score. EFW undergrowth, low birth weight (LBW) and small-for-gestational-age were defined as the categorized outcomes. Generalized estimating equations and generalized linear regression were used to examine the associations of PM with quantitative and categorized outcomes, controlling for temperature, greenspace and individual covariates.

RESULTS

A 10 μg/m³ increase in PM_2.5 and PM₁₀ were associated with lower EFW Z-score [-0.031, 95% confident interval (CI): -0.047, -0.016 and -0.030, 95% CI: -0.043, -0.017]. A 10 μg/m³ increase in PM_2.5 was associated with lower birth weight Z-score (-0.035, 95% CI: -0.061, -0.010) and higher risk of LBW (OR = 1.240, 95% CI: 1.019, 1.508). These results remained robust in co-pollutant models and sensitivity analyses. We didn't find significant results in other analyses.

CONCLUSIONS

The study identified an inverse association between PM and fetal growth in utero. The association between PM_2.5 and fetal growth persisted from pregnancy to birth. This study supported that further actions towards controlling air pollution are strongly recommended for promoting early-life health.

Risk of particulate matter on birth outcomes in relation to maternal socio-economic factors: a systematic review

A growing number of studies provide evidence of an association between exposure to maternal air pollution during pregnancy and adverse birth outcomes including low birth weight and preterm birth. Prevention of these health effects of air pollution is critical to reducing the adverse infant outcomes, which can have impacts throughout the life course. However, there is no consensus on whether the association between air pollution exposure and birth outcomes varies by maternal risk factors including demographic characteristics and socio-economic status. Such information is vital to understand potential environmental health disparities. Our search found 859 unique studies, of which 45 studies met our inclusion criteria (Jan. 2000- July. 2019). We systematically reviewed the 45 identified epidemiologic studies and summarized the results on effect modifications by maternal race/ethnicity, educational attainment, income, and area-level socio-economic status. We considered adverse birth outcomes of preterm birth, low birth weight, small for gestational age (SGA), and stillbirth. Suggestive evidence of higher risk of particulate matter in infants of African-American/black mothers than infants of other women was found for preterm birth and low birth weight. We found weak evidence that particulate matter risk was higher for infants of mothers with lower educational attainment for preterm birth and low birth weight. Due to the small study numbers, we were unable to conclude whether effect modification is present for income, occupation, and area-level socio-economic status, and additional research is needed. Furthermore, adverse birth outcomes such as SGA and stillbirth need more study to understand potential environmental justice issues regarding the impact of particulate matter exposure during pregnancy on birth outcomes.

Racialized Structural Vulnerability: Neighborhood Racial Composition, Concentrated Disadvantage, and Fine Particulate Matter in California

This study contributes to previous research by advancing a “racialized structural vulnerability” framework and presenting a new empirical analysis of the relationship between neighborhood Asian, Black, and Latinx composition; extrinsic and intrinsic vulnerability; and PM_2.5 exposures in California with secondary data from 2004–2014. Principal component analyses revealed that tract Latinx composition was highly correlated with extrinsic vulnerability (economic disadvantage and limited English-speaking ability), and that tract Black composition was highly correlated with intrinsic vulnerability (elevated prevalence of asthma-related emergency department visits and low birth weight). Spatial lag regression models tested hypotheses regarding the association between Asian, Black, and Latinx population vulnerability factors and the 2009–2011 annual average PM_2.5 percentile rankings, net of emissions and spatial covariates. Results indicated that the percent Latinx population, followed by the regional clustering of PM_2.5, and the percent of non-Latinx Black and non-Latinx Asian population were the strongest positive multivariable correlates of PM_2.5 percentile rankings, net of other factors. Additional analyses suggested that despite shifting demographic and spatial correlates of 2012–2014 PM_2.5 exposures, the tracts’ Black and Latinx composition and location in the San Joaquin Valley remain important vulnerability factors with implications for future research and policy.

Association of ambient air pollutants and birth weight in Ningbo, 2015-2017

Previous studies have suggested a change of birth weight linked with elevated ambient air pollutant concentrations during the pregnancy. However, investigations of the influence of higher pollutant levels on birth weight change are limited. The goal of this study is to evaluate whether the air pollution of Ningbo is associated with birth weight, and which trimester could be a window period for maternal exposure to air pollution. A total of 170,008 live births were selected in the Ningbo city of Zhejiang, China, from 2015 to 2017. We estimated the association between the decreased birth weight and the increased air pollutant concentrations in the three trimesters and full gestation. The effects of interaction among pollutants were identified using a co-pollutant adjustment model. An interquartile range increases in PM_2.5 (10.55 μg/m³), SO₂(4.6 μg/m³), CO (125.59 μg/m³), and O₃ (14.54 μg/m³) concentrations during the entire gestation were associated with 3.65 g (95% confidence interval: -6.02 g, -1.29 g), 5.02 g (-6.89 g, -3.14 g), 2.64 g (-4.65 g, -0.63 g) and 2.9 g (-4.8 g, 1 g) decreases, respectively, in birth weight. With each interquartile range increment in NO₂ concentration was associated with an 8.05 g (6.24 g, 9.85 g) increase in birth weight. In the first trimester, only the PM_2.5 exposure seemed to be associated with the greatest decline in birth weight. After adjustment for co-pollutant, both PM_2.5 and SO₂ were still associated with birth weight, except for CO for O₃ adjustment, O₃ for SO₂ adjustment, and O₃ for NO₂ adjustment. Maternal exposure to air pollution may be associated with a decrease of birth weight, but the contribution of various pollutants is necessary to verify by future research.

Identifying the contributions of multiple driving forces to PM10-2.5 pollution in urban areas in China

Economic development and urban expansion have accelerated particulate matter pollution in urban areas in China. Particulate matter-driven haze poses a serious threat to human beings from a public health point of view. Substantial evidences had linked adverse health effects with exposures to PM_2.5, but recent research indicated that PM_10-2.5 also had great risk. However, the relative contributions of driving forces to PM_10-2.5 pollution are not well understood in the urban areas in China, and no targeted policies have been regulated to control the pollution. In this study, we quantified the contributions of potential driving factor across China with the structural equation model (SEM). Our results showed that in 2015 and 2016, the annual average concentrations of PM_10-2.5 in the 290 prefecture-level cities with a mean value of 36 and 35 μg/m³, respectively. Industrial scale contributed more to PM_10-2.5 pollution than city size and residents' activities in urban areas based on SEM results. Driving forces included in our model could explain 42% of variations in PM_10-2.5 pollution, which indicated that there existed influences from other anthropogenic sources and natural sources. Eleven targeted recommendations were then proposed to control PM_10-2.5 pollution based on our mechanism analysis. Findings from our study are beneficial to control PM_10-2.5 pollution on a national scale, and also can provide a theoretical basis for the formulation of PM_10-2.5 pollution control policy in China.