There have been few large multicity studies to evaluate the acute health effects of ambient air pollution on morbidity risk in developing counties. In this study, we examined the short-term associations of air pollution with daily hospital admissions in China. We conducted a nationwide time-series study in 218 Chinese cities between 2014 and 2016. Data on daily hospital admissions counts were obtained from the National Health Insurance Database for Urban Employees covering 0.28 billion enrollees. We used generalized additive model with Poisson regression to estimate the associations in each city, and we performed random-effects meta-analysis to pool the city-specific estimates. More than 60 million hospital admissions were analyzed in this study. At the national-average level, each 10 μg/m³ increase in PM₁₀, SO₂, and NO₂, and 1 mg/m³ increase in CO at lag 0 day was associated with a 0.29% (95% CI, 0.23%–0.36%), 1.16% (95% CI, 0.92%–1.40%), 1.68% (95% CI, 1.40%–1.95%), and 2.59% (95% CI, 1.69%–3.50%) higher daily hospital admissions, respectively. The associations of air pollution with hospital admissions remained statistically significant at levels below the current Chinese Ambient Air Quality Standards. The effect estimates were larger in cities with lower air pollutants levels or higher air temperatures and relative humidity, as well as in the elderly. In conclusion, our findings provide robust evidence of increased hospital admissions in association with short-term exposure to ambient air pollution in China.

Following the Deepwater Horizon (DWH) event in 2010, hydrocarbons were deposited on the continental slope in the northeastern Gulf of Mexico through marine oil snow sedimentation and flocculent accumulation (MOSSFA). The objective of this study was to test the hypothesis that benthic foraminiferal δ13C would record this depositional event. From December 2010 to August 2014, a time-series of sediment cores was collected at two impacted sites and one control site in the northeastern Gulf of Mexico. Short-lived radioisotopes (210Pb and 234Th) were employed to establish the pre-DWH, DWH, and post-DWH intervals. Benthic foraminifera (Cibicidoides spp. and Uvigerina spp.) were isolated from these intervals for δ13C measurement. A modest (0.2–0.4‰), but persistent δ13C depletion in the DWH intervals of impacted sites was observed over a two-year period. This difference was significantly beyond the pre-DWH (background) variability and demonstrated that benthic foraminiferal calcite recorded the depositional event. The longevity of the depletion in the δ13C record suggested that benthic foraminifera may have recorded the change in organic matter caused by MOSSFA from 2010 to 2012. These findings have implications for assessing the subsurface spatial distribution of the DWH MOSSFA event.

A substantial amount of sulfate is often supplied in paddy fields with concomitant applications of chemical fertilizers and manure for rice growth. It is unclear how solubility and speciation of arsenic (As) are affected by the levels of soil sulfate and their relationship to soil redox status and sulfur (S) and iron (Fe) speciation in a short cycle of soil reducing (flooding) and oxidizing (drying) periods. The objective of this study was to investigate the solubility of As in relation to chemical speciation of As and S in different levels of soil sulfate through a time series of measurements during a 40-day reduction period (Eh < −130 mV) followed by a 32-day reoxidation period (Eh > 400 mV) using X-ray absorption fine structure (XAFS) spectroscopy. An excess of sulfate decreased extractable and dissolved As in the soil reducing period due to retardation of soil reduction process that decreased soluble As(III) in the soil solid phase. The As species at the end of soil reducing period were 38–41% As(V), 46–51% As(III), and 11–13% As2S3-like species, regardless of initial S treatments. In the following soil reoxidation, As2S3-like species were sensitive to oxidation and disappeared completely in the first 2 days when the Eh value increased rapidly above 160 mV. The addition of extra sulfate to the soil did not result in the formation of neither reduced S species nor As2S3-like species. About 50% of As(III) to the total As persisted over 32 days of soil reoxidation period (Eh > 400 mV), suggesting some mechanisms against oxidation of As(III) such as physical sequestration in soil microsites. This study demonstrates that the extra SO4 in paddy soils can help mitigate the dissolution of As in reduction and reoxidation periods.

Air pollution is an important public health concern especially for children who are particularly susceptible. Latin America has a large children population, is highly urbanized and levels of pollution are substantially high, making the potential health impact of air pollution quite large. We evaluated the effect of air pollution on children respiratory mortality in four large urban centers: Mexico City, Santiago, Chile, and Sao Paulo and Rio de Janeiro in Brazil.Generalized Additive Models in Poisson regression was used to fit daily time-series of mortality due to respiratory diseases in infants and children, and levels of PM10 and O3. Single lag and constrained polynomial distributed lag models were explored. Analyses were carried out per cause for each age group and each city. Fixed- and random-effects meta-analysis was conducted in order to combine the city-specific results in a single summary estimate.These cities host nearly 43 million people and pollution levels were above the WHO guidelines. For PM10 the percentage increase in risk of death due to respiratory diseases in infants in a fixed effect model was 0.47% (0.09–0.85). For respiratory deaths in children 1–5 years old, the increase in risk was 0.58% (0.08–1.08) while a higher effect was observed for lower respiratory infections (LRI) in children 1–14 years old [1.38% (0.91–1.85)]. For O3, the only summarized estimate statistically significant was for LRI in infants. Analysis by season showed effects of O3 in the warm season for respiratory diseases in infants, while negative effects were observed for respiratory and LRI deaths in children.We provided comparable mortality impact estimates of air pollutants across these cities and age groups. This information is important because many public policies aimed at preventing the adverse effects of pollution on health consider children as the population group that deserves the highest protection.

The association between ambient temperature and mortality has been well documented worldwide. However, limited data are available on nonfatal health outcomes, such as emergency department visits (EDVs), particularly from China.To examine the temperature-EDV association in 12 Chinese cities; and to assess the modification effects by region, gender and age.Daily meteorological data and non-accidental EDVs were collected during 2011–2014. Poisson regression with distributed lag non-linear model was applied to examine the temperature-lag-EDV association in each city. The effect estimates were pooled using multivariate meta-analysis at the national and regional level. Stratified analyses were performed by gender and age-groups. Sensitivity analyses adjusting for air pollution and relative humidity were conducted.A total of 4,443,127 EDVs were collected from the 12 cities. Both cold and hot temperatures were associated with increased risk of EDVs, with minimum-mortality temperature located at 64th percentile of temperature. The effect of cold temperature appeared on day 2 and persisted until day 30, causing a cumulative relative risk (RR) of 1.80 (1.54, 2.11). The effect of hot temperature appeared immediately and lasted until day 3, with a cumulative RR of 1.15 (1.03, 1.29). The effect of temperature on EDVs was similar in male and female but was attenuated with increasing age. The effect of cold temperature on EDVs was greater in southern areas of the country whereas the hot effect was greater in northern cities. The association was robust to a large range of sensitivity analyses.In China, there is a U-shaped association between temperature and risk of EDVs that is independent of air pollution and humidity. The temperature-EDV association varies with latitude and age-groups but is not affected by gender. Forecasting models for hospital emergency departments may be improved if temperature is included as an independent predictor.

Seasonal patterns of birth outcomes have been observed worldwide, and there was increasing evidence that ambient temperature played as a trigger of adverse birth outcomes, such as preterm birth (PTB), low birth weight (LBW), and stillbirth. To systematically review updated epidemiological evidence about the relationship between temperature exposure during pregnancy and PTB, LBW, and stillbirth, we searched for related studies published in English from electronic databases and references of identified papers. We only included original articles that directly reported the effects of prenatal temperature exposure on birth outcomes. The characteristics and main findings of included studies were examined. A total of 36 epidemiological studies were finally included in this review. Most of these studies focused on PTB and LBW, while less attention has been paid to stillbirth that was relatively rare in the occurrence. Several designs including ecological (e.g., descriptive and time-series) and retrospective cohort studies (e.g., case-crossover and time-to-event) were applied to assess temperature effects on birth outcomes. Temperature metrics and exposure windows varied greatly in these investigations. Exposure to high temperature was generally found to be associated with PTB, LBW, and stillbirth, while several studies also reported the adverse impact of low temperature on birth outcomes of PTB and LBW. Despite no conclusive causality demonstrated, the current evidence for adverse effect on birth outcomes was stronger for heat than for cold. In summary, the evidence linking birth outcomes with ambient temperature was still very limited. Consequently, more related studies are needed worldwide and should be conducted in diversified climate zones, so as to further ascertain the association between temperature and birth outcomes. Future studies should focus on more sophisticated study designs, more accurate estimation of temperature exposure during pregnancy, and more efficient methods to find out the exposure windows, as well as cold-related effects on birth outcomes.

Years of life lost (YLL) is a more informative and accurate indicator than daily death counts for assessing air pollution related premature death. However, there is limited evidence available about the relationship of air pollution with YLL, especially in China. We conducted a ten-year (from January 1st, 2001 to December 31st, 2010) multi-district time-series study to estimate the effects of ambient particulate matter with an aerodynamic diameter of less than 10 μm in size (PM10) on daily non-accidental deaths and YLL in six districts of Tianjin, China. Meta-analysis was used to merge the results of the six districts. We found that the increase of PM10 was significantly associated with daily death and YLL in the six districts, except with the YLL in Heping district. 10 μg/m³ increases in PM10 were associated with the maximum increases in excess risk (ER) of death counts of 0.33% (95% confidence interval [CI]: 0.25%, 0.41%) at lag01 and in YLL of 0.80 (95%CI: 0.47, 1.13) person year at lag01 for the combined effects of six districts, respectively. Moreover, the associations of PM10 on daily death counts and YLL were stronger in the elder people (≥65 years) than those in the younger ones (<65 years). These findings may help to shed light on the policy-making of PM-control in China and provide useful information for the protection of susceptible population.

We studied seasonal and physiological influences on mercury concentrations in western grebes (Aechmophorus occidentalis) and Clark's grebes (A. occidentalis) across 29 lakes and reservoirs in California, USA. Additionally, at three of these lakes, we conducted a time series study, in which we repeatedly sampled grebe blood mercury concentrations during the spring, summer, and early fall. Grebe blood mercury concentrations were higher among males (0.61 ± 0.12 μg/g ww) than females (0.52 ± 0.10 μg/g ww), higher among Clark's grebes (0.58 ± 0.12 μg/g ww) than western grebes (0.51 ± 0.10 μg/g ww), and exhibited a strong seasonal pattern (decreasing by 60% from spring to fall). Grebe blood THg concentrations exhibited a shallow, inverse U-shaped pattern with body size, and was lowest among the smallest and largest grebes. Further, the relationship between grebe blood mercury concentrations and wing primary feather molt exhibited a shallow U-shaped pattern, where mercury concentrations were highest among birds that had not yet begun molting, decreased approximately 24% between pre-molt and late molt, and increased approximately 19% from late molt to post-molt. Because grebes did not begin molting until mid-summer, lower grebe blood mercury concentrations observed in late summer and early fall were consistent with the onset of primary feather molt. However, because sampling date was a much stronger predictor of grebe mercury concentrations than molt, other seasonally changing environmental factors likely played a larger role than molt in the seasonal variation in grebe mercury concentrations. In the time series study, we found that seasonal trends in grebe mercury concentrations were not consistent among lakes, indicating that lake-specific variation in mercury dynamics influence the overall seasonal decline in grebe blood mercury concentrations. These results highlight the importance of accounting for sampling date, as well as ecological processes that may influence mercury concentrations, when developing monitoring programs to assess site-specific exposure risk of mercury to wildlife.

Ambient air pollution has been a major global public health issue. A number of studies have shown various adverse effects of ambient air pollution on cardiovascular diseases. In the current study, we investigated the short-term effects of ambient air pollution on emergency room (ER) admissions due to cardiovascular causes in Beijing from 2009 to 2012 using a time-series analysis. A total of 82430 ER cardiovascular admissions were recorded. Different gender (male and female) and age groups (15yrs ≤ age <65 yrs and age ≥ 65 yrs) were also examined by single model and multiple-pollutant model. Three major pollutants (SO2, NO2 and PM10) had lag effects of 0–2 days on cardiovascular ER admissions. The relative risks (95% CI) of per 10 μg/m3 increase in PM10, SO2 and NO2 were 1.008 (0.997–1.020), 1.008(0.999–1.018) and 1.014(1.003–1.024), respectively. The effect was more pronounced in age ≥65 and males in Beijing. We also found the stronger acute effects on the elderly and females at lag 0 than on the younger people and males at lag 2.

Elucidating the driving forces behind the temporal dynamics of abundant and rare microbes is essential for understanding the assembly and succession of microbial communities. Here, we explored the successional trajectories and mechanisms of abundant and rare bacteria via soil-enrichment subcultures in response to various pollutants (phenanthrene, n-octadecane, and CdCl2) using time-series Illumina sequencing datasets. The results reveal different successional patterns of abundant and rare sub-communities in eighty pollutant-degrading consortia and two original soil samples. A temporal decrease in α-diversity and high turnover rate for β-diversity indicate that deterministic processes are the main drivers of the succession of the abundant sub-community; however, the high cumulative species richness indicates that stochastic processes drive the succession of the rare sub-community. A functional prediction showed that abundant bacteria contribute primary functions to the pollutant-degrading consortia, such as amino acid metabolism, cellular responses to stress, and hydrocarbon degradation. Meanwhile, rare bacteria contribute a substantial fraction of auxiliary functions, such as carbohydrate-active enzymes, fermentation, and homoacetogenesis, which indicates their roles as a source of functional diversity. Our study suggests that the temporal succession of microbes in polluted microcosms is mainly associated with abundant bacteria rather than the high proportion of rare taxa. The major forces (i.e., stochastic or deterministic processes) driving microbial succession could be dependent on the low- or high-abundance community members in temporal microcosms with pollutants.