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Constraining the role of dust deposition in regulating the concentration of the essential micronutrient iron in surface ocean waters requires knowledge of the flux of seawater‐soluble iron in aerosols and the replacement time of dissolved iron (DFe) in the euphotic zone. Here we estimate these quantities using seasonally resolved DFe data from the Bermuda Atlantic Time‐series Study region and weekly‐scale measurements of iron in aerosols and rain from Bermuda during 2019. In response to seasonal changes in vertical mixing, primary production and dust deposition, surface DFe concentrations vary from ∼0.2 nM in early spring to >1 nM in late summer, with DFe inventories ranging from ∼30 to ∼80 μmol/m2, respectively, over the upper 200 m. Assuming the upper ocean approximates steady state for DFe on an annual basis, our aerosol and rainwater data require a mean euphotic‐zone residence time of ∼0.8–1.9 years for DFe with respect to aeolian input. Plain Language Summary Primary production by phytoplankton in ocean surface waters is the foundation of the marine ecosystem, and plays a key role in maintaining the ocean‐atmosphere balance of carbon dioxide, which regulates global climate. Iron is an essential micronutrient that is required by phytoplankton, and the availability of dissolved iron (DFe) is thought to limit phytoplankton growth over large areas of the ocean. In this context, it is important to constrain the sources and persistence of DFe in surface ocean waters, which control the amount of DFe that is available to support phytoplankton growth. This study focuses on the Bermuda region of the North Atlantic Ocean, where deposition of airborne soil dust is the major source of DFe to surface waters. By combining measurements of the atmospheric loading and solubility of iron in soil dust over Bermuda with measurements of DFe in adjacent ocean waters over a full year, we are able to estimate the rate of supply of DFe from dust deposition in this region, as well as the average time that this DFe persists in the surface ocean. The latter, termed the DFe replacement time, is around 1 year, which agrees well with recent estimates from comparable ocean regions. Key Points An imbalance between input and removal produces an ∼3‐fold seasonal increase in the euphotic‐zone inventory of dissolved iron (DFe) near Bermuda Analyses of iron in seasonal‐scale aerosol, rain and water‐column samples allow direct estimates of the replacement time of DFe We derive a mean residence time of ∼0.8–1.9 years for DFe in the euphotic zone (<200 m) of the Sargasso Sea near Bermuda

In open oceans, changes in mixed layer depth (MLD) may affect phytoplankton growth and biomass variations via the regulation of nutrient supply from deep waters. Estimates of relationships between variability in phytoplankton dynamics and the MLD remain limited, especially at different time scales. We compiled and analyzed averaged euphotic‐depth‐integrated chlorophyll‐a (IChl‐a) and surface chlorophyll‐a (SChl‐a) concentrations collected from 27 cruises during the period of 1999–2019 in the tropical northern South China Sea (SCS). Seasonal differences existed in both averaged IChl‐a and SChl‐a concentrations, with significantly high concentrations in the cold season. Inconsistent relationships between the averaged IChl‐a and SChl‐a concentrations between seasons implied that the use of SChl‐a concentration as a common indicator of phytoplankton biomass dynamics should be performed with caution. Over the past decades in the northern SCS, the averaged IChl‐a, SChl‐a, and MLD decreased to a greater extent in the cold season than in the warm season, while sea surface temperature (SST) rose rapidly and dramatically in both seasons. The MLD was observed to have better correlations with the averaged IChl‐a and SChl‐a concentrations than the SST in the time‐series data. Our results highlight the importance of IChl‐a concentration, which is an overall measure of phytoplankton responses to euphotic zone conditions, and the MLD could be used as a good index for changes in phytoplankton biomass under climate change. Plain Language Summary Given that ocean stratification, corresponding to mixed layer depth (MLD), is critical of phytoplankton growth and biomass variations under climate change, particularly in tropical and subtropical regions, it is important to examine MLD influences on phytoplankton at multiple temporal scales in those areas. Based on long‐term investigation in the northern South China Sea during the 1999–2019 period, the identification of oceanographic links with phytoplankton, especially its biomass represented by chlorophyll‐a (Chl‐a) concentrations, revealed that high Chl‐a concentrations in the cold season and typhoon disturbance could play an important role in increasing oceanic production. The interannual and decadal observations showed a progressive increase in sea surface temperature and decreases in both MLD and Chl‐a concentrations that may become a severe environmental and biotic crisis in the SCS. To better address contemporary climatic threats, measurements of phytoplankton responses in the euphotic zone remain essential and may not be simply replaced by recent satellite remote sensing development. Key Points We quantify differences between euphotic‐depth‐integrated chlorophyll‐a (IChl‐a) and surface chlorophyll‐a (SChl‐a) concentrations in the South China Sea Inconsistent relationships between IChl‐a and SChl‐a concentrations between seasons imply caution to use SChl‐a for phytoplankton dynamics The IChl‐a concentration and mixed layer depth could be used as good indices for changes in phytoplankton biomass under climate change

The relationship between exposure to ambient air pollutants and emergency attendance for upper gastrointestinal bleeding (UGIB) remains inconclusive. This study examines the association between short‐term exposure to various ambient pollutants and the risk of UGIB emergency attendance. Data on daily UGIB emergency attendance, ambient pollutants, and meteorological conditions in Hong Kong were collected from 2017 to 2022. A time‐series study using a distributed lag non‐linear model to analyze the data, considering lag days. Stratified analysis was performed based on sex, seasons, and the COVID‐19 pandemic period. The burden was quantified using attributable fraction (AF) and number (AN). The study included 31,577 UGIB emergency records. Exposure to high levels of PM2.5 significantly increased the risk of UGIB emergency attendance from lag day 3 (RR: 1.012) to day 6 (RR: 1.008). High NO2 exposure also posed a significant risk from lag day 0 (RR: 1.026) to day 2 (RR: 1.014), and from lag day 5 (RR: 1.013) to day 7 (RR: 1.024). However, there was no association between UGIB and high O3 levels. The attributable burden of high‐concentration NO2 exposure was higher compared to those of PM2.5. Males and elderly individuals (≥65 years) faced a higher risk of UGIB emergencies, particularly during cold seasons. Our study suggests that both PM2.5 and NO2 exposure are associated with an increased risk of emergency attendance for UGIB. Ambient pollutant exposure has a stronger effect on UGIB in males and the elderly, particularly during cold seasons. Plain Language Summary Our research in Hong Kong from 2017 to 2022 investigated the impact of brief exposure to air pollution on emergency visits for upper gastrointestinal bleeding (UGIB). We examined various types of air pollutants, including fine particulate matter (PM) and ozone, with a specific focus on identifying the most harmful pollutants and their temporal patterns. Our findings demonstrate that even a slight increase in levels of fine PM and nitrogen dioxide can significantly contribute to an upsurge in emergency cases of UGIB. Notably, these effects are more pronounced during colder months and in the elderly. The burden was more severe before the COVID‐19 pandemic. This study underscores the direct influence of air pollution on public health and emphasizes the imperative need to enhance air quality, particularly in densely populated urban areas. Our finding could help to inform public health policies and to promote measures aiming at reducing individuals' exposure to pollutants. Key Points Short‐term exposure to high concentration of PM2.5 and NO2 significantly raise upper gastrointestinal bleeding (UGIB) emergency visits The impact of air pollution on the occurrence of UGIB emergencies is exacerbated by cold weather and among the elderly population The results of our study underscore the necessity for policy interventions aimed at enhancing air quality and promoting health safety

Schizophrenia is a chronic and severe mental disorder affecting more than 21 million people worldwide. Short-term exposure to nitrogen dioxide (NO ) has been associated with hospital admissions (HAs) for mental disorders, but no study has evaluated the specific association of NO and schizophrenia. Additionally, the shape of the concentration-response (C-R) curve has not yet been assessed at present. This study aims to investigate the relationship between short-term exposure to NO and HAs for schizophrenia in Hefei, from 2014 to 2016. We also attempt to explore the C-R and the underlying effect modifiers of the association. Daily number of HAs for schizophrenia was derived from the computerised medical record system of Anhui Mental Health Center. We used a time-series Poisson generalised linear regression combined with distributed lag non-linear models to model the NO -schizophrenia relationship. A total of 11 373 HAs were identified during the study period. An increase in levels of NO was significantly associated with elevated schizophrenia HAs. The estimated relative risk per IQR increase in NO at lag 01 was 1.10 (95% CI 1.01 to 1.18). Greater association was observed in young patients (relative risk: 1.11, 95% CI 1.02 to 1.19). The modelled C-R curves of the NO -schizophrenia relationship suggested possible threshold effects of NO for all ages combined, young patients, men and both seasons. Short-term exposure to NO may be associated with increased schizophrenia HAs. Findings indicated potential threshold effects of NO , which has important implications for health-based risk assessments.

Background Regression modeling methods are commonly used to estimate influenza‐associated mortality using covariates such as laboratory‐confirmed influenza activity in the population as a proxy of influenza incidence. Objective We examined the choices of influenza proxies that can be used from influenza laboratory surveillance data and their impact on influenza‐associated mortality estimates. Method Semiparametric generalized additive models with a smoothing spline were applied on national mortality data from South Africa and influenza surveillance data as covariates to obtain influenza‐associated mortality estimates from respiratory causes from 2009 to 2013. Proxies examined included alternative ways of expressing influenza laboratory surveillance data such as weekly or yearly proportion or rate of positive samples, using influenza subtypes, or total influenza data and expressing the data as influenza season‐specific or across all seasons. Result Based on model fit, weekly proportion and influenza subtype‐specific proxy formulation provided the best fit. The choice of proxies used gave large differences to mortality estimates, but the 95% confidence interval of these estimates overlaps. Conclusion Regardless of proxy chosen, mortality estimates produced may be broadly consistent and not statistically significant for public health practice.

There is a discussion in Europe about the dominant role of air pollution for health effects, most researchers claim that the particulate matter is responsible for inflammatory processes in the respiratory system, while others underline the role of nitrogen dioxide. The aim of the study was to assess the risk related to NOx, NO2 and PM2.5 concentration increase and daily outpatient visits or hospitalization due to bronchitis and asthma exacerbation in the entire population of Silesian Voivodeship, Poland. To assess the relationship between daily pollutants concentrations and the number of outpatient visits or hospitalizations due to bronchitis and asthma (available in the regional registry), the multivariable log-linear Poisson regression model was used. Results were presented by relative risk (RR) of health outcomes related to the increase in pollutant concentration by unit (interquartile range). Obtained results confirmed a statistically significant association between outpatient visits and hospitalizations due to bronchitis and asthma exacerbation and daily nitrogen oxides concentrations in Silesian voivodeship, Poland. The strongest relationship was observed in the case of NO2 and outpatient visits due to bronchitis, e.g., RR = 1.434 (1.308–1.571) for exposure expressed by the 50-day moving average concentration. In the case of hospitalizations, the health effect was lagged a few days in relation to the increase in exposure.

Fine particulate matter (PM 2.5 ) is a mixture of multiple components, which is associated with several chronic diseases, including respiratory and cardiovascular diseases. We evaluated the association between daily PM 2.5 and PM 2.5–10 exposure and hospital visits for respiratory diseases. Hospital visits for respiratory diseases were collected from Yinzhou Health Information System database. We used generalized additive models to examine the excess relative risk (ERR) and 95% confidence interval for hospital visits for respiratory diseases associated with each 10-μg/m 3 increase in PM 2.5 and PM 2.5–10 concentration. Non-linear exposure-response relationship between PM exposure and hospital visits for respiratory diseases was evaluated by a smooth spline. The ERRs for hospital visits for respiratory diseases associated with a 10-μg/m 3 increase in the 6-day cumulative average concentration of PM 2.5 and PM 2.5–10 were 5.40 (95% CI 2.32, 8.57) and 6.37% (95% CI 1.84, 11.10), respectively. The findings remained stable when we adjusted other gaseous air pollution. PM 2.5 and PM 2.5–10 were associated with the increased visits for the acute upper respiratory infection, pneumonia, asthma, and COPD. In this time-series study, we found a positive association between daily particulate matter exposure and hospital visits for respiratory diseases.

Ambient air pollution remains one of the most important risk factors for health outcomes. In recent years, there has been a growing number of research linking particulate matter (PM) exposure with adverse health effects, especially on cardiovascular and respiratory systems. The objective of this review is to examine the range and nature of studies on time series analysis of health outcomes affected by PM2.5 across a broad research area. A literature search was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) extension for scoping review framework through a strategic search of PubMed and ScienceDirect online databases for articles from January 2016 to January 2021. Articles were first screened by their titles and abstracts. Then two reviewers independently reviewed and evaluated the full text of the remaining articles for eligibility. Of the 407 potentially relevant studies, 138 articles were included for final analysis. There was an increasing trend in publications from 2016 to 2019 but a decreasing trend in the year 2020. Most studies were conducted in Eastern and South-Eastern Asia (69.6%), Europe and Northern America (14.5%) and Latin America and the Caribbean (8.7%), with the majority coming from high- and upper-middle-income countries (95.6%). The main methodology used was Generalized Additive Model (GAM) with Poisson distribution (74.6%). Morbidity was the most common health outcome studied (60.1%), with vulnerable groups (64.5%) often included. The association between PM2.5 and health effects was stronger for respiratory diseases compared to cardiovascular diseases. In short-term studies (less than 7 years), respiratory diseases showed higher risks compared to cardiovascular. However, in long-term studies (7 years and more), cardiovascular showed higher risks.

Background Pulmonary space-occupying lesions are typical chronic pulmonary diseases that contribute significantly to healthcare resource use and impose a large disease burden in China. A time-series ecological trend study was conducted to investigate the associations between environmental factors and hospitalizations for pulmonary space-occupying lesions in North of China from 2014 to 2022. Methods The DLNM was used to quantify the association of environmental factors with lung cancer admissions. The heating-, age-, gender-, malignancy-specific effects were further estimated to identify the susceptible groups. Results During the study period, fluctuations in air pollutants and climate conditions closely mirrored changes in hospitalizations for pulmonary space-occupying lesions. Totally, the distributed lag surface showed clear positive associations between pulmonary tumor hospitalization and PM 2.5 (RR lag30 : 1.000912; 95%CI: 1.000076, 1.00175), PM 10 (RR lag30 : 1.002246; 95%CI: 1.000474, 1.004021), SO 2 (RR lag30 : 1.002714; 95%CI: 1.001071, 1.004414), CO (RR lag30 : 1.002231; 95%CI: 1.000592, 1.003873). Additionally, the associations between air pollutants and hospitalizations for pulmonary space-occupying lesions were significantly stronger during the heating season. Population aged 65 or older, females and those diagnosed with malignancies were more vulnerable for the risk of pulmonary space-occupying lesions diseases due to air pollution exposure. Conclusions The present study illustrated risk and burden for pulmonary space-occupying lesions hospitalization associated with air pollution, especially among population aged ≥ 65, or female.

The effects of short-term ambient ozone (O 3 ) exposure on health outcomes have received growing concerns, but its effects on psoriasis is still unclear. The purpose of our study was to investigate the effects of short-term exposure to O 3 on psoriasis, and to find out potential modifiers. A hospital-based time-series study with outpatient visit data of psoriasis was performed in Chongqing, the largest metropolitan in Southeast China. General additive models combined quasi-Poisson regression were implied to reveal the association between short-term exposure to O 3 and psoriasis. Moreover, the potential modifiers were found out through subgroup analyses. Totally, 23,921 psoriasis outpatient visits were included. For the whole patient population, no significant association between exposure to O 3 and outpatient visits for psoriasis was observed. Interestingly, the stratified analyses based on concentrations showed that low concentration of O 3 (below the recommended limitation of 100 μg/m 3 by WHO and China), rather than high concentration of O 3 , was negatively associated with psoriasis outpatient visits at various lag days, and the greatest decrease was observed at lag03 (-2.05%; 95%CI: -3.55%, -0.53%). Moreover, stronger associations were observed in cool seasons, patients aged 40 or above, and males. Additionally, the negative associations of low-concentration O 3 on psoriasis outpatient visits were still robust in sensitivity analyses. Our study discovered that low-concentrations of O 3 , rather than high concentrations of O 3 , can be associated with decreased outpatient visits for psoriasis, especially for males, population aged 40 and above, and in cool seasons.