Joel Schwartz

Ultrafine particles (UFPs) are airborne particles with a diameter of less than 100 nm. They are emitted from various sources, such as traffic, combustion, and industrial processes, and can have adverse effects on human health. Long-term mean ambient average particle size (APS) in the UFP range varies over space within cities, with locations near UFP sources having typically smaller APS. Spatial models for lung deposited surface area (LDSA) within urban areas are limited and currently there is no model for APS in any European city. We collected particle number concentration (PNC), LDSA, and APS data over one-year monitoring campaign from May 2021 to May 2022 across 27 locations and estimated annual mean in Copenhagen, Denmark, and obtained additionally annual mean PNC data from 6 state-owned continuous monitors. We developed 94 predictor variables, and machine learning models (random …

WHO’s tightening of its air quality guidelines is beneficial to health and the environment, but we must go further to reduce air pollution, argue Yaguang Wei and Joel Schwartz

Background Over 120 million people in the USA live in areas with unsafe ozone (O3) levels. Studies among adults have linked exposure to worse lung function and higher risk of asthma and chronic obstructive pulmonary disease (COPD). However, few studies have examined the effects of O3 in children, and existing studies are limited in terms of their geographic scope or outcomes considered. Methods We leveraged a dataset of encounters at 42 US children’s hospitals from 2004–2015. We used a one-stage case-crossover design to quantify the association between daily maximum 8-hour O3 in the county in which the hospital is located and risk of emergency department (ED) visits for any cause and for respiratory disorders, asthma, respiratory infections, allergies and ear disorders. Results Approximately 28 million visits were available during this period …

Fine particulate matter (PM2.5) exposure is adversely linked to atherosclerotic cardiovascular disease (ASCVD). However, most studies focused on PM2.5 mass rather than its chemical composition. PM2.5's individual chemical components can have distinct, cumulative, and potentially synergistic health impacts. We investigated the associations of PM2.5's composition and sources with ASCVD mortality, considering the combined associations and regional variations in the US. We used data from the Centers for Medicare and Medicaid Services, (65,838,403 person-years) from 2000 to 2016. We estimated PM2.5 exposure using machine-learning models and attributed components to five source categories. We used Poisson survival models to assess the associations with the source categories. Higher ASCVD mortality risk (RR [95% CI] per interquartile range increase) was associated with oil combustion (1.050[1.049;1.051]), industrial (1.054[1.052;1.056]), coal/biomass burning (1.064[1.062;1.067]), and traffic sources (1.044[1.042;1.046]). Comparing source-specific effects within each region, oil combustion effects were more pronounced in the East and Midwest, and coal/biomass burning effects were more pronounced in the West and Southwest. In conclusion, we found higher ASCVD mortality risk associated with PM2.5, with differential effects across sources and US regions. These associations persisted even after limiting our sample to ZIP code-years with PM2.5 <9 μg/m3 - the National Ambient Air Quality Standards (NAAQS). This highlights the importance of consideration of local population characteristics and exposure patterns when …

BackgroundAdequate thyroid hormone (TH) availability is required for optimal development of the fetal brain. Untreated permanent congenital hypothyroidism (CHT) typically results in intellectual disability in humans. Newborns with transient-CHT have temporary TH deficiency and will improve to normal TH levels usually in few months.Aims To estimate the associations of prenatal exposure to particulate matter (PM) with CHT and transient-CHT in newborns.MethodsA historical birth cohort study, based on the Israeli national program for neonatal screening, including term infants born in Israel in 2009-2015 (N=696,461). Separate logistic regression models were used to estimate the associations of PM as a continuous variable with CHT and transient-CHT, adjusted for ethnicity, calendar month and year of conception, socioeconomic status, and sub-district. To assess residual confounding, postnatal exposures to the …

BackgroundClimate change can directly impact temperature-related excess deaths and might subsequently change the seasonal variation in mortality. In this study, we aimed to provide a systematic and comprehensive assessment of potential future changes in the seasonal variation, or seasonality, of mortality across different climate zones.MethodsIn this modelling study, we collected daily time series of mean temperature and mortality (all causes or non-external causes only) via the Multi-Country Multi-City Collaborative (MCC) Research Network. These data were collected during overlapping periods, spanning from Jan 1, 1969 to Dec 31, 2020. We projected daily mortality from Jan 1, 2000 to Dec 31, 2099, under four climate change scenarios corresponding to increasing emissions (Shared Socioeconomic Pathways [SSP] scenarios SSP1-2.6, SSP2-4.5, SSP3-7.0, and SSP5-8.5). We compared the seasonality in …

Objective To estimate exposure-response associations between chronic exposure to fine particulate matter (PM2.5) and risks of the first hospital admission for major cardiovascular disease (CVD) subtypes.Design Population based cohort study.Setting Contiguous US.Participants 59 761 494 Medicare fee-for-service beneficiaries aged ≥65 years during 2000-16. Calibrated PM2.5 predictions were linked to each participant’s residential zip code as proxy exposure measurements.Main outcome measures Risk of the first hospital admission during follow-up for ischemic heart disease, cerebrovascular disease, heart failure, cardiomyopathy, arrhythmia, valvular heart disease, thoracic and abdominal aortic aneurysms, or a composite of these CVD subtypes. A causal framework robust against confounding bias and bias arising from errors in exposure measurements was developed for exposure-response estimations …

High-resolution assessment of historical levels is essential for assessing the health effects of ambient air pollution in the large Indian population. The diversity of geography, weather patterns, and progressive urbanization, combined with a sparse ground monitoring network makes it challenging to accurately capture the spatiotemporal patterns of ambient fine particulate matter (PM2.5) pollution in India. We developed a model for daily average ambient PM2.5 between 2008 and 2020 based on monitoring data, meteorology, land use, satellite observations, and emissions inventories. Daily average predictions at each 1 km × 1 km grid from each learner were ensembled using a Gaussian process regression with anisotropic smoothing over spatial coordinates, and regression calibration was used to account for exposure error. Cross-validating by leaving monitors out, the ensemble model had an R2 of 0.86 at …