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[en] Various studies have illustrated that exposure to ambient air pollution has negative impacts on health. However, little evidence exists on the effects of ambient air pollution on circulatory mortality in Xi’an, China. This study aims to investigate and ascertain the association between short-term exposure to ambient air pollutants and circulatory mortality in Xi’an, China. Daily average concentrations of PM2.5, SO2, and O3, meteorological data (temperature and relative humidity) and daily counts of circulatory mortality were obtained between January 2014 and June 2016. Mortality was stratified by gender and age group (≤ 64 years and ≥ 65 years). A generalized additive model (GAM) with natural splines (NS) was constructed to analyze the relationship between ambient air pollutants and daily circulatory mortality. There were 57,570 cases of circulatory mortality, with cerebrovascular and ischemic heart diseases accounting for 48.5% and 43.5%, respectively. All ambient air pollutants displayed different seasonal patterns. In the single pollutant model, 10 μg/m3 increase in 2-day moving average concentrations of PM2.5, SO2, and O3 was associated with relative risk of 1.288(1.198, 1.388), 1.360(0.877, 2.331), and 1.324(1.059, 1.705) in circulatory mortality, respectively. After adjusting for collinearity in the multi-pollutant model, the effects remained statistically significant. The ≥ 65 years and female sub-groups were associated with a higher risk of circulatory mortality. Short-term exposure to ambient air pollutants plays a pivotal role in the genesis of circulatory mortality in Xi’an. Responses to ambient air pollutants exposure in relation to circulatory mortality are different when analyzed by sub-groups.
[en] Sulfur dioxide is a major air pollutant in the environment. Fortunately, the plant purification system can effectively reduce SO2 pollution. However, the effect mechanism of plant purification system for the dynamic evolution of SO2 remains incompletely clear. In this work, inspired by the “Boston ivy,” we successfully designed and constructed a semi-continuous plant system. Subsequently, based on the “vine-like plant” and the “island-like plant,” the semi-continuous plant system and the isolated plant system are selected as the models of plant purification system, respectively. The dynamic evolution of SO2 in the plant systems is investigated using the computational fluid dynamic (CFD) method. It is demonstrated that the dynamic evolution of SO2 is impacted by the plant structure and the flow path ((cg/lg) + (cl/ll)). In the semi-continuous plant system, the strong flow paths with gradually weakened fluctuation are restricted by this special plant structure, the length of flow paths are extended, and more SO2 can be dissolved. In the isolated plant system, the mild flow paths with linear relationship can easily pass through the plants, such that only a little SO2 is dissolved. Overall, the present study opens a new path into the dynamic evolution of SO2 pollution in the plant systems, which helps providing guidance for the designing of plant purification system.
[en] We performed a time series analysis to investigate the potential association between exposure to ambient air pollution and type 2 diabetes (T2D) incidence in the Chinese population. Monthly time series data between 2008 and 2015 on ambient air pollutants and incident T2D (N = 25,130) were obtained from the Environment Monitoring Center of Ningbo and the Chronic Disease Surveillance System of Ningbo. Relative risks (RRs) and 95% confidence intervals (95% CIs) of incident T2D per 10 μg/m3 increases in ambient air pollutants were estimated from Poisson generalized additive models. Exposure to particulate matter < 10 μm (PM10) and sulfur dioxide (SO2) was associated with increased T2D incidence. The relative risks (RRs) of each increment in 10 μg/m3 of PM10 and SO2 were 1.62 (95% CI, 1.16–2.28) and 1.63 (95% CI, 1.12–2.38) for overall participants, whereas for ozone (O3) exposure, the RRs were 0.78 (95% CI, 0.68–0.90) for overall participants, 0.78 (95% CI, 0.69–0.90) for males, and 0.78 (95% CI, 0.67–0.91) for females, respectively. Exposure to PM10 and SO2 is positively associated with T2D incidence, whereas O3 is negatively associated with T2D incidence.
[en] The effect of HSO3− on the electrochemical migration (ECM) of Sn–3.0Ag–0.5Cu lead-free solder alloy under thin electrolyte layers was investigated using the thin electrolyte layer method. The results showed that the migration element of Sn–3.0Ag–0.5Cu alloy was Sn and the faster-growing branch of the dendrite resulted in a sharper tip during the dendrite growth process. Increasing the amount of HSO3− decreased the probability of ECM. Due to the hydrolysis of HSO3, the pH value of electrolyte in thin electrolyte layer shifted toward a strongly acidic environment and a lower pH condition was favorable for dendrite formation. However, HSO3− reacted with tin ions to form some insoluble compounds during the ECM process, resulting in a decrease of tin ion concentration under thin electrolyte layers. A protective film formed on the anode surface, thus blocking the anodic dissolution process. Possible reactions were proposed to explain the inhibitory effect of HSO3− on the ECM of Sn–3.0Ag–0.5Cu alloy.
[en] China’s economic boom has created many environmental and health challenges, including so-called cancer villages. This study, the first to use the lens of “cancer villages” at provincial level, examines the correlation between changes in Jiangsu cancer villages and economic and environmental quality indicators identified as being relevant, and hence to highlight environmental issues that should be mitigated to protect public health. Since 2001, 25 cancer villages have been reported in Jiangsu. The distribution pattern of these villages is of a cluster whose mean centre had moved from Suzhou city in 2001 to Taizhou in 2006 and 2011. By applying the buffer analysis tool of ArcGIS10.2.2 using 3-km and 5-km radius buffer, to examine the relationship between these cancer villages and the surrounding rivers, it was revealed that 76% of the villages fall within the 3-km buffer zone, and 88% are within the 5-km buffer zone. A fairly strong correlation between the cancer villages and annual GDP, as well as pollutant discharge, was found, with correlation coefficients of 0.94 for Jiangsu, 0.89 for Northern Jiangsu, 0.93 for Central Jiangsu, 0.83 for Southern Jiangsu and 0.64 for city level. The change of newly added cancer villages is significantly influenced by the discharge of sewage water (raising COD) and SO2, and the peak of newly added cancer villages, as well as discharge of COD and SO2 all occurred in 2005. For four cities, the total sewage water discharge and SO2 emissions are consistent with the order of the distribution density of the villages. The phenomenon of cancer villages in China will gradually be resolved as the government takes effective measures to tackle environmental issues coupled with people’s increasing environmental and health awareness.
[en] Highlights: *The oxidation of SO2 over Si-doped graphene is studied. *Both Langmuir-Hinshelwood (LH) and Eley-Rideal (ER) mechanisms are considered. *Si-doped graphene can be used as a metal-free catalyst for oxidation of SO2. This study reports favorable reaction mechanisms of SO2 oxidation by molecular O2 over Si-doped graphene by means of DFT calculations. The SO2 oxidation reaction proceeds through the following elementary steps (a) SO2 + O2 - Oads + SO3 and (b) Oads + SO2 - SO3. It is found that the first and second steps are fulfilled via the Langmuir-Hinshelwood (LH) and Eley-Rideal (ER) mechanisms, with an activation energy of 4.7 and 9.5 kcal/mol, respectively. Results show that the low-cost Si-doped graphene can be used as an efficient catalyst for SO2 oxidation at room temperature.
[en] Environmental regulations affect employment through productivity output and factor substitution. This paper employs a difference-in-differences (DID) method to investigate the effect of China’s Two Control Zones (TCZ) policy on the urban employment in 287 cities from 1994 to 2009. We apply the DID method to two time points: 1998 for policy issuance and 2000 for the policy implementation. From the results of analyses on full-sample cities, the TCZ policy did not contribute to increasing total urban employment. Moreover, a negative impact on employment resulted from sulfur dioxide and acid rain controls in secondary and tertiary industries, respectively. In the acid rain control zone, the TCZ policy increased the average wage of urban workers. Negative effects on employment were observed in larger cities. The policy triggered labor migration from larger to smaller cities, resulting in significant increases in primary and tertiary industry employment in smaller cities, although the effects on mid-size cities were insignificant. This study provides important empirical evidence and insight into the impact of the TCZ policy on urban employment.
[en] Despite the Mediterranean Sea basin is among the most sensitive areas over the world for climate change and air quality issues, it still remains less studied than the oceanic regions. The domain investigated by the research ship Minerva Uno cruise in Summer 2015 was the Tyrrhenian Sea. An overview on the marine boundary layer (MBL) concentration levels of carbonyl compounds, ozone (O3), and sulfur dioxide (SO2) is reported. The north-western Tyrrhenian Sea samples showed a statistically significant difference in acetone and SO2 concentrations when compared to the south-eastern ones. Acetone and SO2 values were higher in the southern part of the basin; presumably, a blend of natural (including volcanism) and anthropogenic (shipping) sources caused this difference. The mean acetone concentration reached 5.4 μg/m3; formaldehyde and acetaldehyde means were equal to 1.1 μg/m3 and 0.38 μg/m3, respectively. Maximums of 3.0 μg/m3 for formaldehyde and 1.0 μg/m3 for acetaldehyde were detected along the route from Civitavecchia to Fiumicino. These two compounds were also present at levels above the average in proximity of petrol-refining plants on the coast; in fact, formaldehyde reached 1.56 μg/m3 and 1.60 μg/m3, respectively, near Milazzo and Augusta harbors; meanwhile, acetaldehyde was as high as 0.75 μg/m3 at both sites. The levels of formaldehyde agreed with previously reported measurements over Mediterranean Sea and elsewhere; besides, a day/night trend was observed, confirming the importance of photochemical formation for this pollutant. According to this study, Mediterranean Sea basin, which is a closed sea, was confirmed to suffer a high anthropic pressure impacting with diffuse emissions, while natural contribution to pollution could come from volcanic activity, particularly in the south-eastern Tyrrhenian Sea region.
[en] China’s residents experience unequal exposure to air pollution in different regions, and the corresponding health consequences have increased remarkably. To ensure sustainable development, China should monitor health inequality and its potential determinants. This study empirically examines the health inequalities (represented by perinatal and tuberculosis mortalities) caused by air pollution inequalities (represented by SO2 and NOx emissions) from 31 Chinese provinces in the period 2006 to 2015, using the generalized method of moments (GMM) and quantile regression (QR). The GMM results reveal a strong positive relationship between SO2/NOx emission inequality and tuberculosis mortality inequality. In contrast, the QR results show that perinatal mortality inequality is closely related to emission inequality across all percentiles for SO2 emission and at the 75th percentile for NOx emission. Our findings help policymakers to identify health disparities and be mindful of air pollution inequality as a factor in the elimination of health inequality.
[en] Evolution of submicron particles in terms of particle number concentration and mobility-equivalent diameter was measured during Diwali festival–specific intensive pyrotechnic displays in Varanasi over central Indo-Gangetic Plain (IGP). A scanning mobility particle sizer coupled with an optical particle sizer was used to fit in an overlapping size range, and particle number concentration was analyzed to have an insight into the new particle formation and subsequent evolution of particles from nucleation to accumulation mode. Further, variation in black carbon (BC) concentration and aerosol ionic composition was measured simultaneously. Frequent fluctuation in particle number concentration in and around Diwali festival was evidenced, primarily influenced by local emission sources and meteorology, with three distinct peaks in number concentrations (dN/dlogDp, 3.1–4.5 × 104 cm3) coinciding well with peak firework emission period (18:00–23:00 h). Submicron particle size distribution revealed a single peak covering a size range of 80–130 nm, and for all instances, number concentration maximum coincided with geometric mean minimum, indicating the emission primarily in the ultrafine range (< 0.1 μm). Interestingly, during peak firework emissions, besides rise in accumulation mode, an event of new particle formation was identified with increase in nucleation and small Aitken mode, before being dispersed to background aerosols. On an integral scale, a clear distinction was noted between a normal and an episodic event, with a definite shift in the formation of ultrafine particles compared with the accumulation mode. The BC diurnal profile was typical, with a prominent nocturnal peak (12.0 ± 3.9 μg m-3) corresponding to a decrease in the boundary layer height. A slight variation in maximum BC concentration (16.8 μg m-3) was noted in the night of the event coinciding well with firework emissions. An increase in some specific ionic species was also noted in combination with an increase in the overall cation to anion ratio, which was explained in terms of heterogeneous transformation of NOx and catalytic conversion of SO2. .