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Air pollution poses a global concern due to its detrimental effects on climate, healthcare, and human capital accumulation. However, there is limited evidence on the health and human capital impacts of clean air transport policies. This study investigates the effects of London’s Low Emission Zone (LEZ) and Ultra-Low Emission Zone (ULEZ) on air quality, sick leave, well-being, and physical health. By exploiting the temporal and spatial variations of these policies – implemented in Greater London (LEZ) in 2008 and Central London (ULEZ) in 2019 – we implement a difference-in-differences approach utilising linked survey and administrative data. We show that the LEZ and ULEZ policies significantly reduced PM10 and NO2 levels. Consequently, we observe substantial improvements in labour productivity, with sick leave reduced by 18.5% from pre-LEZ levels. The ULEZ contributed to enhanced mental well-being, as evidenced by increased feelings of happiness, worthiness and satisfaction, along with a reduction in anxiety. These effects are further supported by improvements in physical health, with the LEZ reducing the incidence of long-term health conditions by 6.8% and respiratory issues by 10.2%. A back-of-the-envelope cost–benefit analysis suggests that the policies generated savings exceeding £37 million per year for the overall population.

Published Jun 1, 2025

Beshir, H. A., & Fichera, E. (2025). “And Breathe Normally”: Impacts of low emission zones on sick leave and mental well-being. Journal of Economic Behavior & Organization, 234, 106994. https://doi.org/10.1016/J.JEBO.2025.106994

The co-occurrence of fine particulate matter (PM2.5) and ozone has emerged as a critical environmental challenge in recent years. The individual harmful impacts of PM2.5 and ozone exposure have been well studied; however, their combined toxicity under co-exposure conditions remains mechanistically undefined. This paper provides an extensive evaluation of the current pollution levels, epidemiological investigation, and new findings on the toxicological mechanisms of combined exposure to PM2.5 and ozone. The synergistic toxicity of PM2.5 and ozone depends on different factors, including the physicochemical properties of PM2.5, the dose and duration of exposure, and the specific target organs. Through extensive research, we identified the main targets of toxic responses to PM2.5 and ozone exposure and summarized their synergistic toxic mechanisms. Given the current research priorities, there is an urgent need to improve scientific research regarding PM2.5 and ozone co-exposure with priority given to characterizing their properties and toxicological responses while updating relevant guidelines and standards.

Published Mar 24, 2025

He, J., Wang, T., Li, H., Zhou, Y., Liu, Y., & Xu, A. (2025). Synergistic Toxicity of Fine Particulate Matter and Ozone and Their Underlying Mechanisms. Toxics 2025, Vol. 13, Page 236, 13(4), 236. https://doi.org/10.3390/toxics13040236

Background
Alzheimer's disease and Alzheimer's disease-related dementias (AD/ADRD) are prevalent neurodegenerative disorders, posing a critical worldwide public health challenge. Ambient air pollution has been identified as a potential risk factor for AD progression based on toxicological and epidemiological studies. We aimed to evaluate the impacts of air pollution—including fine particulate matter (PM2·5), nitrogen dioxide (NO2), summer ozone (O3), and oxidant—on readmission or death among Medicare enrollees previously hospitalised with an AD/ADRD diagnosis code.
Methods
We constructed a population-based nationwide retrospective cohort including all Medicare fee-for-service beneficiaries (aged ≥65 years) in the contiguous USA (2000–16) hospitalised with AD/ADRD, and followed them up from the year after their first hospitalisation until (1) year of death (mortality cohort) and (2) year of second hospitalisation for any cause (readmission cohort). We calculated annual average PM2·5, NO2, summer O3, and oxidant concentrations for each individual at their residential ZIP code in each year after their first hospitalisation with AD/ADRD. We applied Cox proportional hazard models for the mortality and readmission cohorts stratifying on individual risk factors and adjusting for socioeconomic status, seasonal temperatures, and relative humidity.
Findings
Our cohort consisted of 5 544 118 individuals, of whom 4 543 759 (82·0%) died and 3 880 894 (70·0%) were readmitted to the hospital during the study period. The average follow-up times were 3·34 years (SD 2·60) for the mortality cohort and 1·98 years (SD 1·65) for the readmission cohort. In both the mortality and readmission cohorts we found significant associations with each pollutant. For an IQR increase in NO2, we found a hazard ratio (HR) for mortality of 1·012 (95% CI 1·009–1·015) and an HR for readmission of 1·110 (1·104–1·117). In the readmission cohort, we found an HR of 1·084 (1·079–1·089) for an IQR increase (3·87 μg/m3) in PM2·5. The results slightly decreased in multi-pollutant models. The results of effect modification for mortality and readmission varied by pollutant, but higher risks were found among Black males and among those eligible for Medicaid in general.

Published Feb 1, 2025

Dong, S., Braun, D., Wu, X., Yitshak-Sade, M., Blacker, D., Kioumourtzoglou, M. A., Schwartz, J., Mork, D., Dominici, F., & Zanobetti, A. (2025). The impacts of air pollution on mortality and hospital readmission among Medicare beneficiaries with Alzheimer’s disease and Alzheimer’s disease-related dementias: a national retrospective cohort study in the USA. The Lancet Planetary Health, 9(2), e114–e123. https://doi.org/10.1016/S2542-5196(25)00001-4

Climate change and extreme weather events are particularly concerning for pregnant and postpartum women and have been related to negative birth outcomes. However, the impact of climate change on perinatal mental health outcomes is not well studied. Mood and anxiety disorders are among the leading comorbidities during pregnancy and the postpartum period, and they are associated with significant familial and societal burdens. It is crucial to include environmental factors in the risk profile of perinatal mental illness to optimize prevention and early intervention strategies. In the clinical experience of one of the authors, new mothers can feel particularly concerned about their baby’s physical health when faced with extreme heat or may present as agitated due to heat-related sleep deprivation. This is in line with qualitative research showing maternal worrying about a baby’s thermal dysregulation as one of the emerging themes. With extreme weather events becoming more frequent, clinicians have a role in advocating for climate adaptation in healthcare settings. Climate inequalities need to be addressed alongside health and social inequalities.

Published Jan 20, 2025

Barkin, J. L., van Rhijn, S., & Johnson, C. M. (2024). The connection between climate change and perinatal mental health. Frontiers in Psychiatry, 15, 1515895. https://doi.org/10.3389/FPSYT.2024.1515895/BIBTEX

In the United States (US), neonatal intensive care units (NICUs) monitor and treat newborns for a variety of adverse health concerns including preterm status, respiratory distress and restricted growth. As such, NICU admission is an integrated measure of neonatal risk. We linked 2018 US national birth registry NICU admission data among singleton births with satellite and modelled air pollution levels for the month prior to birth to examine whether late-pregnancy exposure to ambient air pollutants is associated with adverse neonatal health outcomes. Regardless of season, higher ambient levels of nitrogen dioxide (NO2) and fine particulate matter < 2.5 microns (PM2.5) increased the likelihood of NICU admission 30–35% for NO2 and 11–22% for PM2.5 even after adjustment for parental characteristics. Results for ozone exposure were inconsistent with largely null or reduced risk except for summer months. Despite the relatively low-moderate US exposure levels, traffic-related pollutants near the end of pregnancy appear to increase overall adverse health risks for newborns, underscoring the need to reduce prenatal exposure to ambient pollutants.

Published Jan 2, 2025

Phiri, Y. V. A., Canty, T., Nobles, C., Ring, A. M., Nie, J., & Mendola, P. (2025). Neonatal intensive care admissions and exposure to satellite-derived air pollutants in the United States, 2018. Scientific Reports 2024 15:1, 15(1), 420-. https://doi.org/10.1038/s41598-024-84755-9

Background
A growing body of epidemiologic and toxicologic literature indicates that fine airborne particulate matter (PM2.5) pollution is neurotoxic and threatens children’s neurobehavioral development, resulting in reduced cognitive function. Understanding the magnitude of this effect is critical for establishing public health policies that will protect children’s health, preserve human capital, and support societal progress.

Objective
To quantify the association between ambient PM2.5 air pollution and loss of cognitive function in children, as measured by Intelligence Quotient (IQ) scores, through a systematic literature review and meta-analysis.

Methods
Following PRISMA guidelines, we conducted a systematic literature search across seven databases: Agricultural and Environmental Science, BIOSIS Citation Index, Embase, GreenFILE, PubMed, Scopus, and Web of Science to identify original scientific studies that investigated the impact of PM2.5 exposure during pre-and postnatal periods on IQ loss during childhood. Using data from studies included for final review, we conducted a meta-analysis, using a random effects model to compute a beta coefficient that quantifies the overall effect of PM2.5 exposure on Full-Scale IQ (FSIQ), Performance IQ (PIQ), and Verbal IQ (VIQ).

Findings
Of the 1,107 unique publications identified, six studies met the inclusion criteria for final review, representing 4,860 children across three continents (North America, Europe, and Asia). The mean PM2.5 concentration across all studies was 30.4 ± 24.4 µg/m3. Exposure timing ranged from the prenatal period to mid-childhood. Children were an average of 8.9 years old at the time of cognitive testing. We found that each 1 µg/m3 increase in PM2.5 concentration is associated with a -0.27 point change in FSIQ (p < 0.001), 0.39 point change in PIQ (p = 0.003), and -0.24 point change in VIQ (p = 0.021). Conclusion Through a systematic review and meta-analysis, we identified a statistically significant relationship between increased exposure to PM2.5 air pollution and reduced cognitive function in children, with the most pronounced impact on PIQ. This analysis will enable estimation of the burden of adverse neurobehavioral development attributable to PM2.5 in pediatric populations and will inform local and global strategies for exposure prevention.

Published Dec 1, 2024

Alter, N. C., Whitman, E. M., Bellinger, D. C., & Landrigan, P. J. (2024). Quantifying the association between PM2.5 air pollution and IQ loss in children: a systematic review and meta-analysis. Environmental Health: A Global Access Science Source, 23(1), 1–17. https://doi.org/10.1186/S12940-024-01122-X/TABLES/8

Background:
Though observational studies have widely linked air pollution exposure to various chronic diseases, evidence comparing different exposures in the same people is limited. This study examined associations between changes in air pollution exposure due to relocation and the incidence and mortality of 14 major diseases.
Methods:
We included 50,522 participants enrolled in the UK Biobank from 2006 to 2010. Exposures to particulate matter with a diameter ≤2.5μ⁢m (PM2.5), particulate matter with a diameter ≤10μ⁢m (PM10), nitrogen oxides (NOx), nitrogen dioxide (NO2), and sulfur dioxide (SO2) were estimated for each participant based on their residential address and relocation experience during the follow-up. Nine exposure groups were classified based on changes in long-term exposures due to residential mobility. Incidence and mortality of 14 major diseases were identified through linkages to hospital inpatient records and death registries. Cox proportional hazard models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for incidence and mortality of the 14 diseases of interest.
Results:
During a median follow-up of 12.6 years, 29,869 participants were diagnosed with any disease of interest, and 3,144 died. Significantly increased risk of disease and all-cause mortality was observed among individuals who moved from a lower to higher air polluted area. Compared with constantly low exposure, moving from low to moderate PM2.5 exposure was associated with increased risk of all 14 diseases but not for all-cause mortality, with adjusted HRs (95% CIs) ranging from 1.18 (1.05, 1.33) to 1.48 (1.30, 1.69); moving from low to high PM2.5 areas increased risk of all 14 diseases: infections [1.37 (1.19, 1.58)], blood diseases [1.57 (1.34, 1.84)], endocrine diseases [1.77 (1.50, 2.09)], mental and behavioral disorders [1.93 (1.68, 2.21)], nervous system diseases [1.51 (1.32, 1.74)], ocular diseases [1.76 (1.56, 1.98)], ear disorders [1.58 (1.35, 1.86)], circulatory diseases [1.59 (1.42, 1.78)], respiratory diseases [1.51 (1.33, 1.72)], digestive diseases [1.74 (1.58, 1.92)], skin diseases [1.39 (1.22, 1.58)], musculoskeletal diseases [1.62 (1.45, 1.81)], genitourinary diseases [1.54 (1.36, 1.74)] and cancer [1.42 (1.24, 1.63)]. We observed similar associations for PM10 and SO2 with 14 diseases (but not with all-cause mortality); increases in NO2 and NOx were positively associated with 14 diseases and all-cause mortality.
Conclusions:
This study supports potential associations between ambient air pollution exposure and morbidity as well as mortality. Findings also emphasize the importance of maintaining consistently low levels of air pollution to protect the public’s health.

Published Sep 30, 2024

Chen, G., Qian, Z., Zhang, J., Wang, X., Zhang, Z., Cai, M., Arnold, L. D., Abresch, C., Wang, C., Liu, Y., Fan, Q., & Lin, H. (2024). Associations between Changes in Exposure to Air Pollutants due to Relocation and the Incidence of 14 Major Disease Categories and All-Cause Mortality: A Natural Experiment Study. Environmental Health Perspectives, 132(9), 097012-1-097012–12. https://doi.org/10.1289/EHP14367

Importance: Growing evidence associates air pollution exposure with various psychiatric disorders. However, the importance of early-life (eg, prenatal) air pollution exposure to mental health during youth is poorly understood, and few longitudinal studies have investigated the association of noise pollution with youth mental health.

Objectives: To examine the longitudinal associations of air and noise pollution exposure in pregnancy, childhood, and adolescence with psychotic experiences, depression, and anxiety in youths from ages 13 to 24 years.

Design, Setting, and Participants: This cohort study used data from the Avon Longitudinal Study of Parents and Children, an ongoing longitudinal birth cohort founded in 1991 through 1993 in Southwest England, United Kingdom. The cohort includes over 14 000 infants with due dates between April 1, 1991, and December 31, 1992, who were subsequently followed up into adulthood. Data were analyzed October 29, 2021, to March 11, 2024.

Exposures: A novel linkage (completed in 2020) was performed to link high-resolution (100 m2) estimates of nitrogen dioxide (NO2), fine particulate matter under 2.5 μm (PM2.5), and noise pollution to home addresses from pregnancy to 12 years of age.

Main outcomes and measures: Psychotic experiences, depression, and anxiety were measured at ages 13, 18, and 24 years. Logistic regression models controlled for key individual-, family-, and area-level confounders.

Results: This cohort study included 9065 participants who had any mental health data, of whom (with sample size varying by parameter) 51.4% (4657 of 9051) were female, 19.5% (1544 of 7910) reported psychotic experiences, 11.4% (947 of 8344) reported depression, and 9.7% (811 of 8398) reported anxiety. Mean (SD) age at follow-up was 24.5 (0.8) years. After covariate adjustment, IQR increases (0.72 μg/m3) in PM2.5 levels during pregnancy (adjusted odds ratio [AOR], 1.11 [95% CI, 1.04-1.19]; P = .002) and during childhood (AOR, 1.09 [95% CI, 1.00-1.10]; P = .04) were associated with elevated odds for psychotic experiences. Pregnancy PM2.5 exposure was also associated with depression (AOR, 1.10 [95% CI, 1.02-1.18]; P = .01). Higher noise pollution exposure in childhood (AOR, 1.19 [95% CI, 1.03-1.38]; P = .02) and adolescence (AOR, 1.22 [95% CI, 1.02-1.45]; P = .03) was associated with elevated odds for anxiety.

Conclusions and Relevance: In this longitudinal cohort study, early-life air and noise pollution exposure were prospectively associated with 3 common mental health problems from adolescence to young adulthood. There was a degree of specificity in terms of pollutant-timing-outcome associations. Interventions to reduce air and noise pollution exposure (eg, clean air zones) could potentially improve population mental health. Replication using quasi-experimental designs is now needed to shed further light on the underlying causes of these associations.

Published May 28, 2024

Newbury, J. B., Heron, J., Kirkbride, J. B., Fisher, H. L., Bakolis, I., Boyd, A., Thomas, R., & Zammit, S. (2024). Air and Noise Pollution Exposure in Early Life and Mental Health From Adolescence to Young Adulthood. JAMA Network Open, 7(5), e2412169–e2412169. https://doi.org/10.1001/JAMANETWORKOPEN.2024.12169

Electric school buses have been proposed as an alternative to reduce the health and climate impacts of the current U.S. school bus fleet, of which a substantial share are highly polluting old diesel vehicles. However, the climate and health benefits of electric school buses are not well known. As they are substantially more costly than diesel buses, assessing their benefits is needed to inform policy decisions. We assess the health benefits of electric school buses in the United States from reduced adult mortality and childhood asthma onset risks due to exposure to ambient fine particulate matter (PM2.5). We also evaluate climate benefits from reduced greenhouse-gas emissions. We find that replacing the average diesel bus in the U.S. fleet in 2017 with an electric bus yields $84,200 in total benefits. Climate benefits amount to $40,400/bus, whereas health benefits amount to $43,800/bus due to 4.42*10−3 fewer PM2.5-attributable deaths ($40,000 of total) and 7.42*10−3 fewer PM2.5-attributable new childhood asthma cases ($3,700 of total). However, health benefits of electric buses vary substantially by driving location and model year (MY) of the diesel buses they replace. Replacing old, MY 2005 diesel buses in large cities yields $207,200/bus in health benefits and is likely cost-beneficial, although other policies that accelerate fleet turnover in these areas deserve consideration. Electric school buses driven in rural areas achieve small health benefits from reduced exposure to ambient PM2.5. Further research assessing benefits of reduced exposure to in-cabin air pollution among children riding buses would be valuable to inform policy decisions.

Published May 20, 2024

Choma, E. F., Robinson, L. A., & Nadeau, K. C. (2024). Adopting electric school buses in the United States: Health and climate benefits. Proceedings of the National Academy of Sciences of the United States of America, 121(22), e2320338121. https://doi.org/10.1073/PNAS.2320338121/SUPPL_FILE/PNAS.2320338121.SD06.CSV

Importance: Students who ride older school buses are often exposed to high levels of exhaust during their commutes, which may adversely affect health and school attendance. As a result, the US Environmental Protection Agency (EPA) has awarded millions of dollars to school districts to replace older, highly polluting school buses with newer, cleaner buses.

Objective: To leverage the EPA’s randomized allocation of funding under the 2012-2016 School Bus Rebate Programs to estimate the association between replacing old, highly polluting buses and changes in district-average standardized test scores.

Design, Setting, and Participants: This study examined changes in reading and language arts (RLA) and math test scores among US school district applicants to the EPA’s 2012-2016 national School Bus Rebate Programs 1 year before and after each lottery by selection status. Data analysis was conducted from January 15 to July 30, 2023.

Exposure: Selection to receive EPA funding to replace older school buses with newer, cleaner alternatives.

Main Outcomes and Measures: School district changes in RLA and math test scores among students in grades 3 through 8 before and after the EPA funding lotteries by selection status were measured using an intention-to-treat approach.

Results: This study included 1941 school district applicants to the 2012-2106 EPA School Bus Rebate Programs. These districts had a mean (SD) of 14.6 (33.7) schools per district, 8755 (23 776) students per district, and 41.3% (20.2%) of students with free lunch eligibility. Among the applicants, 209 districts (11%) were selected for the clean bus funding. District-average student test scores did not improve among selected districts overall. In secondary analyses, however, districts replacing the oldest, highest polluting buses (ie, pre-1990) experienced significantly greater improvements in district-average test scores in the year after the lottery for RLA and math (SD improvement in test scores, 0.062 [95% CI, 0.050-0.074] and 0.025 [95% CI, 0.011-0.039], respectively) compared with districts without replacements.

Conclusions and Relevance: In this study, the EPA funding was not associated with student test scores overall, but in secondary analyses, the replacement of the oldest school buses was associated with improved educational performance. These findings support prioritizing clean bus replacement of the oldest buses as an actionable way for improving students’ educational performance.

Published Mar 20, 2024

Pedde, M., Szpiro, A., Hirth, R. A., & Adar, S. D. (2024). School Bus Rebate Program and Student Educational Performance Test Scores. JAMA Network Open, 7(3), e243121–e243121. https://doi.org/10.1001/JAMANETWORKOPEN.2024.3121