Jing Cai

Urban subway systems represent important yet understudied environments for human exposure to airborne microorganisms. Therefore, we conducted an investigation of air microbiome across 43 underground stations spanning 13 lines of the Shanghai subway. Using stratified cluster sampling, we simultaneously collected total suspended particles (TSP, aerodynamic diameter ≤ 100 μm) and fine particulate matter (PM2.5, aerodynamic diameter ≤ 2.5 μm) at station entrances, halls, and platforms, integrating microbial taxonomy, transcriptional potential, PM2.5 chemical composition, microclimate, and network topology. We found bacteria dominated both particle-size fractions and accounted for the majority of transcriptional signals, whereas eukaryotic taxa were strongly enriched in TSP, reflecting pronounced particle-size filtering. Although transcriptional potential generally increased with abundance, dominant taxa such as Staphylococcus and Bacillus exhibited weak abundance–transcription coupling, indicating functional decoupling between numerical dominance and transcriptional contribution in subway air microbiomes. Microbial diversity and community composition remained broadly homogeneous across the subway network, consistent with extensive passenger mobility and high network connectivity. In contrast, finer-scale heterogeneity emerged within stations, particularly for eukaryotic communities, which declined from entrances to enclosed platform environments. Environmental associated factors exhibited kingdom-specific patterns: bacterial and viral diversity were primarily associated with local microclimatic conditions, especially temperature, whereas eukaryotic diversity was more strongly linked to urbanization and externally derived aerosol inputs. Overall, these findings demonstrate that subway airborne microbiomes are shaped by interacting effects of particle-size filtering, environmental selection, and network-driven microbial mixing.

Long-term exposure to benzene, toluene, ethylbenzene, and xylene (BTEX) has been linked to preterm birth (PTB), yet evidence from China remains limited. This study included 4,321,599 live singleton births from the National Free Preconception Health Examination Project between 2010 and 2015. Prenatal BTEX exposure was estimated using a chemistry-climate model. Multivariate linear regression and logistic regression models were applied to examine associations of BTEX exposure with gestational age and PTB risk, respectively. For the entire pregnancy, each interquartile range (IQR, 11.6 μg/m3) increase in BTEX exposure was associated with a reduction of 0.138 (95% confidence interval [CI]: 0.133–0.142) weeks in gestational age and a 23% (odds ratio [OR]: 1.23, 95% CI: 1.22–1.24) increase in PTB risk. Among individual components, IQR increases in benzene, toluene, and xylenes concentrations were associated with 21% (95% CI: 20–22%), 25% (95% CI: 24–26%), and 20% (95% CI: 19–21%) higher odds of PTB, respectively. The strongest associations were observed for exposures during the third trimester for both BTEX (OR = 1.27, 95% CI: 1.26–1.28) and individual components (benzene: OR = 1.25, 95% CI: 1.24–1.26; toluene: OR = 1.29, 95% CI: 1.28–1.30; and xylenes: OR = 1.25, 95% CI: 1.24–1.26). Subgroup analyses indicated that the associations were more pronounced among male fetuses, mothers who were overweight or obese, engaged in farming, or had lower educational attainment. Prenatal BTEX exposure was significantly associated with an elevated risk of PTB, emphasizing the potential adverse effects of BTEX pollution on maternal and infant health.

The impact of air pollution on the prognosis of cervical cancer (CC) remains unclear. This study examined the associations of major air pollutants on recurrence and mortality among CC patients. We enrolled 3,758 women diagnosed with primary CC at the Obstetrics and Gynecology Hospital of Fudan University between 2019 and 2022, following them annually until June 2024. Air pollution exposure was estimated using high-resolution spatiotemporal models based on residential addresses. Weighted Cox proportional hazards models based on the Fine–Gray approach were used to estimate the risk of recurrence, while stratified Cox proportional hazards models were used to estimate the risk of death, adjusting for demographic, clinical, and meteorological factors. Among the patients (median follow-up ∼ 3 years), 217 recurrences (5.8%) and 113 deaths (3.0%) occurred. Each interquartile range increase in fine particulate matter (PM2.5), inhalable particulate matter (PM10), nitrogen dioxide (NO2), and sulfur dioxide (SO2) was associated with elevated recurrence risk, with subdistribution hazard ratios (SHRs) of 1.93 (95% Confidence Interval (CI): 1.40–2.66), 1.65 (1.13–2.42), 1.60 (1.14–2.24), and 1.26 (1.07–1.48), respectively. Higher exposure to PM2.5, PM10, and NO2 was also linked to increased mortality risk, with hazard ratios (HRs) of 2.55 (95% CI: 1.78–3.67), 2.21 (1.38–3.54), and 1.37 (1.03–1.84), respectively. No significant association was observed for ozone (O3). Exposure–response and sensitivity analyses supported these findings. This cohort study provides the first evidence that long-term exposure to air pollution after surgery is associated with increased risks of recurrence and mortality in primary CC patients, highlighting it as a modifiable environmental determinant of CC prognosis.

While the link between ambient air pollution and hypertensive disorders of pregnancy (HDP) is well-established, evidence regarding ultrafine particulate matter (UFP), which may exhibit greater toxicity than PM2.5, remains limited, and the underlying mechanisms are poorly understood. We examined the associations of prepregnancy and gestational exposure to UFP and the risk of HDP and its subtypes. Additionally, we investigated the potential mediating role of homocysteine (Hcy) and assessed effect modification by Hcy-related nutrients. We analyzed data from a birth cohort conducted in Shanghai, China, between 2017 and 2018 (N = 7569). Individual UFP exposure was estimated using a high-spatiotemporal-resolution prediction model based on participants’ residential addresses. Data on HDP diagnosis and subtypes were obtained from the Hospital Information System. The levels of serum Hcy, folic acid, and vitamin B12 (VB12) were measured during early pregnancy. Poisson regression models with robust error variance were used to evaluate associations between UFP exposure and HDP and its subtypes. Mediation analysis was performed to assess the role of Hcy during the first trimester in the association between UFP and pre-eclampsia (PE). Stratified analysis was conducted to examine potential effect modification by B-group vitamins. Positive associations were observed between UFP exposure during the prepregnancy period, the first trimester, and the second trimester, and the risks of HDP and PE. Per interquartile range (IQR) increase in UFP, relative risks (RRs) ranged from 1.15 to 1.23 for HDP and 1.29 to 1.41 for PE. UFP exposure during prepregnancy and the first trimester was positively associated with Hcy levels, which in turn were associated with increased PE risk (RR = 1.49, 95% CI: 1.04–2.13). Mediation analysis indicated that Hcy mediated 8.87% and 2.51% of the associations between PE and prepregnancy and first-trimester UFP exposure, respectively. Stratified analysis by VB12 levels showed that the association between UFP and PE was significant only in the low-VB12 group and not in the high-VB12 group. Ambient UFP exposure is associated with an increased risk of HDP and PE. Hcy partially mediates the relationship between UFP exposure and PE. Adequate VB12 levels in early pregnancy may mitigate the risk of UFP-related HDP.

Existing evidence on long-term ozone exposure and total mortality was mainly from Europe and the United States, with inconsistent findings. In China, there is a critical lack of localized cohort-based evidence on this association to inform air quality standard revisions. In this nationwide cohort study of 96,955 adults across 31 Chinese provinces, peak-season and warm-season ozone exposure were estimated using a previously developed random forest model. Stratified Cox proportional hazards models were employed to examine the associations between long-term ozone exposure and nonaccidental mortality and to characterize their exposure–response relationships. In the fully adjusted model, each 10 μg/m3 increase in peak-season and warm-season average ozone concentrations was associated with increased nonaccidental mortality risks of 3.0% (hazard ratio [HR] = 1.030; 95% CI: 1.010, 1.050) and 2.9% (HR = 1.029; 1.010, 1.048), respectively. The exposure–response curves provided weak evidence for a threshold effect of long-term ozone exposure. We estimated that 487,207 (95% UI: 168,705, 786,351) deaths could be attributed to long-term ozone exposure in China in 2019. These findings underscore an urgent need to establish standards for semiannual average ozone concentrations and to strengthen ozone air pollution control.

Developmental delays represent a significant public health issue among preschoolers. Previous research has linked noise to emotional or behavioral problems in children; however, the association between noise and developmental delays remains unclear. To examine this association, a total of 12,130 children aged 3 to 5.5 years were included from 226 kindergartens in Shanghai, China. Neurodevelopment was assessed using the Chinese version of the Ages & Stages Questionnaires-Third Edition, and individual residential noise exposure (LAeq, 40 min) was estimated using a land-use regression model. Higher noise exposure was associated with lower performance in communication, motor, and problem-solving domains. Specifically, each interquartile range [4 dB(A)] increase in noise exposure was significantly associated with a decrease in gross motor scores (0.25, 95% CI, 0.04-0.47) and an increase in the suspected developmental delay (SDD) odds (OR = 1.08; 95% CI, 1.01-1.15) and domain-specific delays, particularly in communication (OR = 1.13; 95% CI, 1.01-1.27) and gross motor (OR = 1.11; 95% CI, 1.03-1.19). Stratified analyses showed higher estimates of ORs for SDD associated with noise exposure in boys and those who were delivered by cesarean section, exclusively breastfed for <6 months, and whose mothers were unemployed. Our findings suggest that ambient noise exposure may adversely affect early neurodevelopment in preschoolers.