Association of fine particulate matter with glucose and lipid metabolism: a longitudinal study in young adults.

OBJECTIVES: This study aimed to evaluate whether PM2.5 exposure in a highly polluted area (>100 µg/m3) affects glucose and lipid metabolism in healthy adults. METHODS: We recruited 110 healthy adults in Baoding city, Hebei, China, and followed them up between 2017 and 2018. Personal air samplers were used to monitor personal PM2.5 levels. Eight glucose and lipid metabolism parameters were quantified. We performed the linear mixed-effect models to investigate the relationships between PM2.5 and glucose and lipid metabolism parameters. Stratified analyses were further performed according to sex and body mass index (BMI). RESULTS: The concentration of PM2.5 was the highest in spring, with a median of 232 µg/m3 and the lowest in autumn (139 µg/m3). After adjusting for potential confounders, we found that for each twofold increase in PM2.5, the median of insulin concentration decreased by 5.89% (95% CI -10.91% to -0.58%; p<0.05), and ox-LDL increased by 6.43% (95% CI 2.21% to 10.82%; p<0.05). Stratified analyses indicated that the associations were more pronounced in females, overweight and obese participants. CONCLUSIONS: Exposure to high PM2.5 may have deleterious effects on glucose and lipid metabolism. Females, overweight and obese participants are more vulnerable.

Patterns and sociodemographic determinants of water intake by children in China: results from the first national population-based survey.

PURPOSE: Accurate data on water and beverage intakes are essential for assessing hydration adequacy and setting proper guidelines. The objective of this study is to identify the patterns and sociodemographic determinants of water intake and to assess the intake adequacy for children in China. METHODS: The study team recruited 41,439 children aged 6-17 years using a multi-stage cluster random sampling method. Daily water and beverage intakes were investigated with the standard questionnaires and measuring containers in face-to-face interviews. Each participant was assigned an adjustment weight to obtain a nationally representative sample. Sociodemographic factors influencing water intake were identified using multi-variable regressions. Water intake adequacy was evaluated by comparing with the recommended water intake (RWI). RESULTS: The mean ± standard deviation of total water intake (TWI) was 1603 ± 731 mL/day for boys and 1487 ± 661 mL/day for girls. Plain water, food moisture, and other beverages contributed 51%, 20%, and 29% of the TWI. Multi-variable analyses showed that TWI of children increased with age, in urban areas and day schools, and with parents' economic and educational levels. The majority (82%) of children had TWI not meeting the corresponding RWI, and the percentage increased with age except for 14-17-year-old boys. CONCLUSIONS: Plain water is still the major source of daily water intake by children in China. Unfortunately, the majority of children do not have sufficient water intake, which warrants future actions and guidelines targeting adequate hydration.

Gold nanoparticles embedded in silica hollow nanospheres induced by compressed CO2 as an efficient catalyst for selective oxidation.

Metal nanoparticles embedded in hollow materials are important due to their wide applications in catalysis. In this work, we disclosed a nontraditional synthetic pathway to prepare silica hollow nanospheres by hydrothermal treatment in the presence of compressed CO2. Especially, the silica hollow nanospheres with an outer diameter of about 16 nm and an inner pore size of 7 nm were obtained using 1.0 MPa CO2. The formation mechanism of silica hollow nanospheres induced by CO2 was investigated by high-pressured UV/Vis spectroscopy. Moreover, gold nanoparticles (2.5 nm) embedded in the silica hollow nanospheres were prepared by a one-pot synthesis using HAuCl4 as a precursor. The current synthetic route of nano-catalysts was simple and facile, in which no etching agent was needed in the process of the hollow material preparation. Besides, this nano-catalyst showed an excellent catalytic performance in epoxidation of styrene with high conversion (82.2%) and selectivity (90.2%) toward styrene oxide, as well as in the selective oxidation of ethylbenzene with good conversion (26.6%) and selectivity (87.8%) toward acetophenone. Moreover, the Au nanoparticles (AuNPs) embedded in silica hollow nanospheres exhibited an excellent recyclability in both the oxidation reactions.

Health risk assessment of dietary exposure to polycyclic aromatic hydrocarbons in Taiyuan, China.

Sixteen polycyclic aromatic hydrocarbons (PAHs) were determined in 24 duplicate-diet samples from people in Taiyuan during summer and winter in 2009. Dietary intake of PAHs for 2862 participants was subsequently estimated by a survey in Taiyuan. Results from these 24 samples were compared with a raw food study in Taiyuan in 2008. Three main sources of dietary PAHs are vegetables, wheat flour and fruits, the sum of which contributes 75.95% of PAHs in dietary food. Compared to the estimated value in raw food, much more B[a]P(eq) (benzo[a]pyrene equivalents) were detected in food samples collected in the duplicate-diet study in Taiyuan (60.75 ng/day). The cooking process may introduce more B[a]P(eq) into food, and the relative contribution of 16 PAHs in the diet would be changed during the cooking procedure.

Exploring particle concentrations and inside-to-outside ratios in vehicles: A real-time road test study.

In transportation microenvironments, humans exposed to particulate matter (PM) inside vehicles can experience higher levels of daily exposure. To make inside-vehicle PM exposure measurements more feasible and easy under real driving conditions, and to quantify the relationship between the concentrations and influencing factors, we assessed PM1, PM2.5, and PM10. levels. Additionally, we collected key influencing factors to develop predictive models. The measurements of PM1, PM2.5, and PM10 concentrations showed that the ventilation setting was a significant influencing factor. The concentrations decreased significantly under the recirculation setting (RC) compared to the outside air setting (OA). The inside-to-outside (I/O) ratios of PM were 1.69 to 1.93-fold higher than those of RC under OA conditions. However, a substantial reduction in the I/O ratios was observed when RC was employed. Although both the concentrations and I/O ratios exhibited significant differences, they demonstrated strong potential relationships. PM2.5 I/O ratios accounted for over 85 % of the variation in the PM1 and PM10 I/O ratios. The developed models for the I/O ratios of PM accounted for >40 and 60 % of the variation in the measured I/O ratios for RC and OA, respectively. We used the vehicle age, vehicle interior volume, speed, cabin temperature, cabin humidity, and their higher-order terms as predictive variables. It is important to note that the influential predictive feature importance differed under RC and OA, and considering the vehicle characteristics between vehicles of the same type may be necessary when using RC. Overall, these findings indicate that the inside-vehicle PM exposure can be measured more easily under real driving conditions by considering the key influencing factors and utilizing the developed predictive models.

The synergistic effect of high temperature and relative humidity on non-accidental deaths at different urbanization levels.

Numerous studies have examined the impact of temperature on mortality, yet research on the combined effect of temperature and humidity on non-accidental deaths remains limited. This study investigates the synergistic impact of high temperature and humidity on non-accidental deaths in China, assessing the influence of urban development and urbanization level. Utilizing the distributed lag nonlinear model (DLNM) of quasi-Poisson regression, we analyzed the relationship between Wet Bulb Globe Temperature (WBGT) and non-accidental deaths in 30 Chinese cities from 2010 to 2016, including Guangzhou during 2012-2016. We stratified temperature and humidity across these cities to evaluate the influence of varying humidity levels on deaths under high temperatures. Then, we graded the duration of heat and humidity in these cities to assess the impact of deaths with different durations. Additionally, the cities were categorized based on gross domestic product (GDP), and a vulnerability index was calculated to examine the impact of urban development and urbanization level on non-accidental deaths. Our findings reveal a pronounced synergistic effect of high temperature and humidity on non-accidental deaths, particularly at elevated humidity levels. The synergies of high temperature and humidity are extremely complex. Moreover, the longer the duration of high temperature and humidity, the higher the risk of non-accidental death. Furthermore, areas with higher urbanization exhibited lower relative risks (RR) associated with the synergistic effects of heat and humidity. Consequently, it is imperative to focus on damp-heat related mortality among vulnerable populations in less developed regions.

Cooperative effects in catalytic hydrogenation regulated by both the cation and anion of an ionic liquid.

The use of transition-metal nanoparticles/ionic liquid (IL) as a thermoregulated and recyclable catalytic system for hydrogenation has been investigated under mild conditions. The functionalized ionic liquid was composed of poly(ethylene glycol)-functionalized alkylimidazolium as the cation and tris(meta-sulfonatophenyl)phosphine ([P(C(6)H(4)-m-SO(3))(3)](3-)) as the anion. Ethyl acetate was chosen as the thermomorphic solvent to avoid the use of toxic organic solvents. Due to a cooperative effect regulated by both the cation and anion of the ionic liquid, the nanocatalysts displayed distinguished temperature-dependent phase behavior and excellent catalytic activity and selectivity, coupled with high stability. In the hydrogenation of α,ß-unsaturated aldehydes, the ionic-liquid-stabilized palladium and rhodium nanoparticles exhibited higher selectivity for the hydrogenation of the C=C bonds than commercially available catalysts (Pd/C and Rh/C). We believe that the anion of the ionic liquid, [P(C(6)H(4)-m-SO(3))(3)](3-), plays a role in changing the surrounding electronic characteristics of the nanoparticles through its coordination capacity, whereas the poly(ethylene glycol)-functionalized alkylimidazolium cation is responsible for the thermomorphic properties of the nanocatalyst in ethyl acetate. The present catalytic systems can be employed for the hydrogenation of a wide range of substrates bearing different functional groups. The catalysts could be easily separated from the products by thermoregulated phase separation and efficiently recycled ten times without significant changes in their catalytic activity.

Mapping the personal PM2.5 exposure of China's population using random forest.

Ambient monitoring may cause estimation errors, and wearable monitoring is expensive and labor-intensive when assessing PM2.5 personal exposure. Estimation errors have limited the development of exposure science and environmental epidemiology. Thus, we developed a scenario-based exposure (SBE) model that covered 8 outdoor exposure scenarios and 1 indoor scenario with corresponding time-activity patterns in Baoding City. The linear regression analysis of the SBE yielded an R2 value of 0.913 with satisfactory accuracy and reliability. To apply the SBE model to large-scale studies, we predicted time-activity patterns with the random forest model and atmosphere-to-scenario ratios with the linear regression model to obtain the essential parameters of the SBE model; their R2 was 0.65-0.93. The developed model would economize the study expenditure of field sampling for personal PM2.5 and deepen the understanding of the influences of indoor and outdoor factors on personal PM2.5. Using this method, we found that the personal PM2.5 exposure of Chinese residents was 10.50-347.02 µg/m3 in 2020, higher than the atmospheric PM2.5 concentration. Residents in North and Central China, especially the Beijing-Tianjin-Hebei region and the Fen-Wei Plains, had higher personal PM2.5 exposure than those in other areas.

Understanding the time-activity pattern to improve the measurement of personal exposure: An exploratory and experimental research.

Although ambient fine particulate matter (PM2.5) concentrations and their components are commonly used as proxies for personal exposure monitoring, developing an accurate and cost-effective method to use these proxies for personal exposure measurement continues to pose a significant challenge. Herein, we propose a scenario-based exposure model to precisely estimate personal exposure level of heavy metal(loid)s (HMs) using scenario HMs concentrations and time-activity patterns. Personal exposure levels and ambient pollution levels for PM2.5 and HMs differed significantly with corresponding personal/ambient ratios of approximately 2, and exposure scenarios could narrow the assessment error gap by 26.1-45.4%. Using a scenario-based exposure model, we assessed the associated health risks of a large sample population and identified that the carcinogenic risk of As exceeded 1 × 10-6, while we observed non-carcinogenic risks from As, Cd, Ni, and Mn in personal exposure to PM2.5. We conclude that the scenario-based exposure model is a preferential alternative for monitoring personal exposure compared to ambient concentrations. This method ensures the feasibility of personal exposure monitoring and health risk assessments in large-scale studies.

Heavy metals in daily meals and food ingredients in the Yangtze River Delta and their probabilistic health risk assessment.

Heavy metal exposure via food consumption is inadequately investigated and deserves considerable attention. We collected hundreds of food ingredients and daily meals and assessed their probabilistic health risk using a Monte Carlo simulation based on an ingestion rate investigation. The detected concentrations of four heavy metals (Cr, Cd, Pb, and Hg) in all daily meal samples were within the limits stipulated in the National Food Safety Standard (GB 2762-2017), while that for As level was excessive in 0.3 % of daily meal samples. The same results were also observed in most food ingredient samples, and a standard-exceeding ratio of 23 % of As was observed in aquatic food or products, especially seafood, which was with the highest concentration reaching 1.24 mg/kg. Combining the detected heavy metal amounts with the ingestion rate investigation, the hazard quotients (HQs) of As, Cr, Cd, Pb, and Hg in daily meals and food ingredients were all calculated as lower than 1 (no obvious harm), while the incremental lifetime cancer risk (ILCR) of As and Cr (>1 × 10-4), indicating that the residual As posed potential health effects to human health. It was noteworthy that the proportion of aquatic foods only accounted for 6.3 % of daily meals, but they occupied 41.1 % of the heavy metal exposure, which could be attributed to the high amounts of heavy metals in aquatic foods. This study not only provided basic data of heavy metal exposure and potential health risks through daily oral dietary intake, but also illuminated the contribution of different kinds of food ingredients. Specifically, the study highlighted the contamination of aquatic foods with As, especially seafood such as shellfish and bivalves.

Reliability and accuracy analysis of time-weighted average exposure to heavy metals based on personal exposure.

Time-weighted average (TWA) exposure has been used as a surrogate for personal air exposure in some large-scale studies. However, the uncertainties of TWA exposure remain to be determined, although its boundedness has been widely recognized. This study aims to evaluate the reliability and accuracy of TWA exposure based on personal exposure. A total of 180 combined indoor-outdoor-personal air samples were collected of six cities during the non-heating and heating periods. The personal exposure levels of Hg, As, Cd, and Pb were 0.16, 21.20, 0.74, and 34.47 ng/m3 in the non-heating period, respectively, but were 0.20, 34.53, 3.45, and 18.59 ng/m3 in the heating period, respectively. The ratios of TWA and personal exposure of heavy metal(loid)s ranged from 0.91 to 1.53. Indoor pollution was the most significant factor of TWA exposure, accounting for 78.3-97.6% and 88.4-98.6% in the heating and non-heating period, respectively. Based on the results of redundancy analysis and risk assessment by TWA exposure, we concluded that TWA exposure could be used for qualitative investigation, as a substitute for personal exposure, but it may result in large bias when used for quantitative investigation. Larger sample size and more exposure scenarios can reduce the estimation error of TWA.

[Influence of PM2.5 Pollution on Health Burden and Economic Loss in China].

Research on health and the economic losses caused by PM2.5 pollution nationwide is critical for pollution control planning. First, the spatiotemporal distribution of PM2.5 and exposure levels were simulated and analyzed using the air quality model (WRF-Chem) in China in 2016. Then, the health burden and economic loss caused by PM2.5 pollution were estimated using environmental health risk and environmental value assessment methods. Finally, the health and economic benefits from achieving specific PM2.5 control targets were estimated. In 2016 in China, high levels of PM2.5 were concentrated in Beijing-Tianjin-Hebei and the surrounding areas, the Yangtze River Delta, the Sichuan Basin, and the desert areas in northwest China. Furthermore, 71.49% of the total population of China was exposed to an environment with PM2.5 concentrations higher than 35 µg·m-3. Subsequently, the national PM2.5-related mortality was 1.06 million, accounting for 10.9% of the total deaths in China. Stroke and ischemic heart disease accounted for approximately 80% of the total PM2.5-related deaths caused by the five diseases studied. Meanwhile, the PM2.5 pollution resulted in economic losses of 705.93 billion yuan, which was 0.95% of the Gross Domestic Product (GDP) in 2016. There were significant spatial differences in the health burden and economic loss, which primarily occurred in regions with high PM2.5 levels or population density. Moreover, reducing PM2.5 to 35 µg·m-3 would only result in a 17.11% reduction in the health burden and economic loss, while a more exacting standard (reducing PM2.5 to 10 µg·m-3) would bring 80.47% of the health and economic benefits. It is suggested that environmental managers further strengthen their control to better protect the health and wealth benefits of residents, especially for sensitive groups, such as patients with cardio-cerebrovascular diseases, particularly in areas with high premature mortality.

[Characteristics of Heavy Metal Pollution and Ecological Risk Evaluation of Indoor Dust from Urban and Rural Areas in Taiyuan City During the Heating Season].

The presence of heavy metals in indoor dust is a world-wide concern owing to its negative impact on humans. In this study, we collected indoor dust samples from urban and rural residential areas during the heating season in Taiyuan City. We then identified the concentrations of 11 heavy metals (Cd, Co, Cr, Pb, Mn, Ni, Cu, Zn, V, As, and Hg) using inductively coupled plasma-mass spectrometry. Based on the concentrations, we categorized the pollution levels of indoor dust using the geo-accumulation index and the pollution load index. We further identified the sources of heavy metals using the enrichment factor and principal component analysis. Finally, we evaluated the potential ecological risks of heavy metals via the potential ecological index. The results illustrated that ① with the exception of Co, Mn, and V, the mean concentrations of Cd, Cr, Cu, Ni, Pb, As, Zn, and Hg in indoor dust were higher than the soil background values of Shanxi Province. There was a significant difference (P<0.05) in the concentrations of Co, Cr, Cu, Mn, Ni, and Hg between the urban and rural areas. ② Overall, the pollution degree of heavy metals in indoor dust was identified as moderate in the urban area of Taiyuan City, but slight in the rural area. The indoor dust sample in the urban area was not contaminated by Co, Mn, and V. However, it was slightly polluted by As, Ni, and Hg. In addition, it was close to moderately polluted by Cd, Cr, Cu, Pb, and Zn. In the rural area, the pollution degrees of all the metals, except for Hg and V, in indoor dust were lower than those in the urban area. ③ The As, Cd, Cu, Pb, Zn, and Hg in indoor dust for both urban and rural areas might have mainly originated from anthropogenic sources. The pollution sources were mainly transportation and industry in the urban area and coal combustion and indoor smoking in the rural area. The Co, Cr, Mn, Ni, and V in indoor dust in Taiyuan City might have mainly originated from natural sources. ④ The ecological risk of heavy metal pollution in indoor dust for both the urban and rural areas of Taiyuan City was relatively high, with integrated ecological risk indexes of 359.43 and 471.02 in the urban and rural areas, respectively. In addition, Cd and Hg were the largest contributors.

Premature mortality attributable to PM2.5 pollution in China during 2008-2016: Underlying causes and responses to emission reductions.

Long-term exposure to fine particulate matter (PM2.5) poses a great threat to public health in China. To this end, the Chinese government promulgated the Air Pollution Prevention and Control Action Plan (the Action Plan) in 2013. However, the health benefits of the Action Plan have not been well explained. In this paper, the underlying causes of changes in premature mortality attributable to PM2.5 pollution and the response of this mitigation policy in China were explored using sensitivity analysis. The simulated annual average PM2.5 concentration reduced by 24.9% over mainland China from 2008 to 2016. Subsequently, national premature mortality would decrease by 14.4% from 1.14 million (95% CI: 0.54, 1.55) in 2008 to 0.98 million (95% CI: 0.44, 1.38) in 2016. Specifically, premature mortality reduced by 209,600 cases (-18.3%) owing to PM2.5 reduction during 2008-2016, of which 188,500 cases were from 2014 to 2016 due to the Action Plan in 2013. Note that the health benefits were limited when compared with air quality improvements, mainly due to that the IER functions have a stable curve at higher concentration intervals. Meanwhile, premature mortality would have increased by 14.2% from 2008 to 2016 owing to demographic changes, substantially weakening the impact of the decrease in PM2.5 and baseline mortality. The effectiveness of China's new air pollution mitigation policy was proved through the research. However, considering the non-linear response of mortality to PM2.5 changes and the aggravation of demography trends, stronger emission control steps should be further taken to protect public health in China.

Characteristics, source apportionment and health risk assessment of heavy metals exposure via household dust from six cities in China.

To investigate the characteristics and health risks of heavy metals in household dust in urban and rural areas during heating and non-heating period in 2016-2017, 762 dust samples and 381 questionnaires from 381 households were collected from Dalian, Taiyuan, Lanzhou, Shanghai, Wuhan, and Chengdu in China. The results indicated that Dalian was the most polluted city, while Shanghai and Chengdu were the least polluted cities during the study period. Longer ventilation times led to higher concentrations of heavy metals, and the weighting of heating duration exceeded that of heating type. Soil was the dominant contributor to household dust for Hg, Ni, Cu, Zn, and As, whereas Pb primarily originated from traffic. The non-carcinogenic and carcinogenic risks associated with heavy metals in household dust were acceptable, with ingestion being the primary exposure route. The risk of adverse health effects caused by heavy metal intake via household dust in urban areas was higher than that in rural areas, and increased during household heating period. Ingestion was the most significant route leading to adverse health effects due to heavy metals in household dust. The exception was the carcinogenic risk associated with Ni, which is known to enter the human body mainly via inhalation.

Internal metal(loid)s are potentially involved in the association between ambient fine particulate matter and blood pressure: A repeated-measurement study in north China.

The effects of ambient fine particulate matter (PM2.5) exposure on blood pressure have been widely reported. However, there remains uncertainty regarding the underlying roles of particulate matter components. We aimed to investigate the association between ambient PM2.5 exposure and blood pressure, as well as the potential effects of trace metal(loid)s, in a repeated-measurement study that enrolled women of childbearing age. Our study included 35 participants from Hebei Province, China, each of whom was visited for five times. During each visit, we conducted questionnaire surveys, measured blood pressure, and collected blood. The daily PM2.5 exposure of participants was estimated according to their residential addresses using a spatiotemporal model that combined monitoring data with satellite measurements and chemical-transport model simulations. This model was used to calculate average PM2.5 concentrations in 1, 3, 7, 15, 30, and 60 days prior to each visit. Serum concentrations of various trace metal(loid)s were measured. A linear mixed-effects model was used to investigate associations among study variables. Overall, the mean (standard deviation) 60 days PM2.5 concentration over all five visits was 108.1(43.3) µg/m3. PM2.5 concentration was positively associated with both systolic and diastolic blood pressures. Likewise, ambient PM2.5 concentration was positively associated with serum concentrations of manganese and arsenic, and negatively associated with serum concentrations of nickel, tin, and chromium. Only the serum concentration of molybdenum was negatively associated with systolic blood pressure. We concluded that ambient PM2.5 exposure may contribute to elevated blood pressure, potentially by interfering with internal intake of various metal(loid)s in the human body.

Contribution of Temperature Increase to Restrain the Transmission of COVID-19.

The COVID-19 outbreak has already become a global pandemic and containing this rapid worldwide transmission is of great challenge. The impacts of temperature and humidity on the COVID-19 transmission rate are still under discussion. Here, we elucidated these relationships by utilizing two unique scenarios, repeated measurement and natural experiment, using the COVID-19 cases reported from January 23 - February 21, 2020, in China. The modeling results revealed that higher temperature was most strongly associated with decreased COVID-19 transmission at a lag time of 8 days. Relative humidity (RH) appeared to have only a slight effect. These findings were verified by assessing SARS-CoV-2 infectivity under the relevant conditions of temperature (4°C-37°C) and RH (> 40%). We concluded that temperature increase made an important, but not determined, contribution to restrain the COVID-19 outbreak in China. It suggests that the emphasis of other effective controlling polices should be strictly implemented to restrain COVID-19 transmission in cold seasons.

Functionalized poly(ethylene glycol)-stabilized water-soluble palladium nanoparticles: property/activity relationship for the aerobic alcohol oxidation in water.

The preparation, characterization, and catalytic properties of water-soluble palladium nanoparticles stabilized by the functionalized-poly(ethylene glycol) as a protective ligand were demonstrated for aerobic oxidation of alcohols in aqueous phase. UV/vis spectra and X-ray photoelectron spectroscopy (XPS) proved that there was an electronic interaction between the bidentate nitrogen ligand and palladium atoms. Transmission electron microscopy and XPS analysis showed that the particle size and surface properties of the generated palladium nanoparticles can be controlled by varying the amount of protective ligand and the kinds of reducing agents. It was found that both the size and surface properties of palladium nanoparticles played very important roles in affecting catalytic performance. The stabilized metallic palladium nanoparticles were proven to be the active centers for benzyl alcohol oxidation in the present system, and the water-soluble Pd nanocatalysts can also be extended to the selective oxidation of various alcohols.

Population based Air Pollution Exposure and its influence factors by Integrating Air Dispersion Modeling with GIS Spatial Analysis.

Air pollution is a major environmental health problem. The study of interaction between air pollution and human will benefit to the human health and well-being of community. Both a model for assessing population relative risk of air pollution exposure (MAPRRAPE) and air pollution concentration methods were applied in a case study to determine the optimal method in evaluating risk of population exposure to Sulfur Dioxide (SO2). The framework for building the MAPRRAPE was described in detail. Then, the spatial patterns of population by demographic characteristics exposed to SO2 from industrial, vehicle, and the mixture of industrial and vehicle pollution sources, as well as an in-depth quantitative investigation using correlation analysis were studied for further source appointment. The results showed that the MAPRRAPE was more reliable than air pollution concentration model in determining population exposure risks by demographic characteristics. The high risk areas of whites exposed to SO2 were larger than blacks and the other races due to a large number of whites, and other age groups exposed to SO2 were larger than children and the old people. In addition, the correlation analyses showed that the relative risks of population by demographic characteristics exposed to SO2 had a more significant correlation with vehicle pollution source than industrial pollution source. The results of source appointment thus demonstrated that vehicle pollution source was the main pollution source. This study suggests that there is a clear need for the implementation of programs and services that will reduce population exposed to air pollution with focusing on densely populated areas for an ultimate improvement of community health status and the environmental conditions.

Specific differences and responses to reductions for premature mortality attributable to ambient PM2.5 in China.

Although recent assessments have quantified the impact of ambient PM2.5 on public health in China, air quality managers would benefit from assessing specific differences in premature mortality and its responses to air quality improvement. Using PM2.5 data simulated by an observation-fused air quality model and an integrated exposure-response model for the full range of PM2.5, we determined the premature mortality attributable to ambient PM2.5 across mainland China in 2016. Overall, the total number of PM2.5-related deaths nationwide was 1.31 million, of which lung cancer, chronic obstructive pulmonary disease, ischemic heart disease, and stroke represented 0.13, 0.13, 0.42, and 0.62 million, respectively. Per capita PM2.5-related mortality in China was 95 per 100,000 person-years, and that of elderly people aged ≥75 years (1166 deaths per 100,000) was much higher than that of young people aged 25-44 years (11 deaths per 100,000). Additionally, there were significant spatial differences in premature deaths, which mainly occurred in regions with high PM2.5 levels or/and population density. Halving deaths across mainland China required an average of 63% reduction of PM2.5 nationwide and a decrease by 73% in high concentration regions exceeding 70 µg/m3 and 19% in low concentration locales below 10 µg/m3. Moreover, reducing PM2.5 to the WHO interim target I (IT-1) of 35 µg/m3 would only result in a 12.6% reduction in premature mortality, while a more exacting standard (reducing PM2.5 to 10 µg/m3) would avoid 73.0% of mortality. In particular, there is a large potential for reducing the high PM2.5-related mortality in heavily polluted locales. In conclusion, to further reduce premature mortality across mainland China, targets stricter than the IT-1 and tight policies to improve air quality and protect public health are necessary, especially for vulnerable groups such as the elderly and patients with cardio-cerebrovascular diseases, particularly in areas with high premature mortality.