[Spatial-temporal Variations and Driving Factors of Surface Ozone over the Qinghai-Xizang Plateau from 2015 to 2021].

The spatial-temporal distribution pattern of surface O3 over the Qinghai-Xizang Plateau （QXP） was analyzed based on air quality monitoring data and meteorological data from 12 cities on the QXP from 2015 to 2021. Kolmogorov-Zurbenko （KZ） filtering was employed to separate the original O3-8h series into components at different time scales. Then, multiple linear regression of meteorological variables was used to quantitatively isolate the effects of meteorology and emissions. The results revealed that the annual mass concentrations of surface O3-8h from 2015 to 2021 in 12 cities over the QXP ranged from 78.7 to 156.7 µg·m-3, and the exceedance rates of O3 mass concentrations （National Air Quality Standard of grade II） ranged from 0.7%-1.5%. The monthly O3-8h mass concentration displayed a single-peak inverted "V"-shape and a multi-peak "M"-shape. The maximum monthly concentration of O3 occurred in April to July, and valleys occurred in July, September, and December. The short-term, seasonal, and long-term components of O3-8hdecomposed by KZ filtering contributed 29.6%, 51.4%, and 9.1% to the total variance in the original O3 sequence in 12 cities, respectively. From the whole region, the meteorological conditions were unfavorable for O3 reduction on the QXP from 2015 to 2017, which made the long-term component of O3 increase by 0.2-2.1 µg·m-3. The meteorological conditions were favorable for O3-8h reduction from 2018 to 2021, which led to the long-term component of O3-8h decrease by 0.4-1.1 µg·m-3. The meteorological conditions increased the long-term component of O3-8h in Ngari, Lhasa, Naqu, Nyingchi, Qamdo, Haixi, and Xining, with an average contribution of 30.1%. The meteorological conditions decreased the long-term component of O3-8h in Shigatse and Golog, with contributions of 359.0% and 56.5%, respectively. The increase in the long-term component of O3-8h in Ngari, Shigatse, Nagqu, Haixi, and Xining could be due to the rapid decrease in the long-term component of PM2.5 （4.04 µg·ï¼ˆm3·a）-1）.

Long-term evolution of carbonaceous aerosols in PM2.5 during over a decade of atmospheric pollution outbreaks and control in polluted central China.

Against the backdrop of an uncertain evolution of carbonaceous aerosols in polluted areas over the long term amid air pollution control measures, this 11-year study (2011-2021) investigated fine particulate matter (PM2.5) and carbonaceous components in polluted central China. Organic carbon (OC) and elemental carbon (EC) averaged 16.5 and 3.4 µg/m3, constituting 16 and 3 % of PM2.5 mass. Carbonaceous aerosols dominated PM2.5 (35 and 27 %) during periods of excellent and good air quality, while polluted days witnessed other components as dominants, with a significant decrease in primary organic aerosols and increased secondary pollution. From 2011 to 2021, OC and EC decreased by 53 and 76 %, displaying a high-value oscillation phase (2011-2015) and a low-value fluctuation phase (post-2016). A substantial reduction in high OC and EC concentrations in 2016 marked a milestone in significant air quality improvement attributed to effective control measures, especially targeting OC and EC, evident from their decreased proportion in PM2.5. Primary OC (POC) in winter exhibited the most pronounced reduction (8 % per year), and the seasonal disparities in PM2.5 and carbonaceous components were reduced, showcasing the effectiveness of control measures. Contrary to the more pronounced reduction of EC, which decreased in proportion to PM2.5, secondary OC (SOC) in PM2.5 exhibited an increasing trend. Along with rising OC/EC, SOC/OC, and SOC/EC ratios, this indicates a growing prominence of secondary pollution compared to the decrease in primary pollution. SOC shows an increasing trend with NO2 rise (r = 0.53), without O3 promoting SOC. Positive correlations of SOC with SO2, CO (r = 0.41, 0.59), also highlight their influence on atmospheric conditions, oxidative capacity, and chemical reactions, indirectly impacting SOC formation. The implementation of precise precursor emission reduction measures holds the key to future efforts in mitigating SOC pollution and reducing PM2.5 concentrations, thereby contributing to improved air quality.

Age evolution of secondary organic aerosol: Impacts of regional transport and aerosol volatility.

In this study, a revised CMAQ model incorporating source and temporal apportioning functions has been used to analyze the aging characteristics of SOA in East Asia. The results show that in the aerosol phase, the fraction of the non-volatile components typically fluctuates around 75 %-95 %, and aromatic hydrocarbon precursors contribute significantly to SOA, accounting for 45.6 %-72.7 % in winter and 29.1 %-52.7 % in summer. Transport due to meteorological conditions does not affect the SOA volatility profile in the cities, while regional source composition has been found to be important for the characterization of the properties of SOA in cities. When the SOA regional composition type is a multi-region-imported-dominated type (MRT), its age composition type tends to be an old-age-SOA-dominated type (OAT) (>48 h). Additionally, transport also causes fluctuations in the range of hourly SOA with atmospheric age of 96 h or higher. The SOAs normally transport through seasonal monsoon and could migrate longer in winter (700-1500 km in January) than in other seasons (250-900 km in April; 500-1200 km in July; 300-1000 km in October). Additionally, in winter, non-volatile SOA generally has a longer transport distance (700-1600 km) than semi- and low-volatile SOA (300-1300 km and 600-1500 km). Furthermore, during the transport process, geographical barriers have negligible impact on SOA in the 48+ hour age group.

Contributions of local emissions and regional background to summertime ozone in central China.

Source contributions and regional transport of maximum daily average 8-h (MDA8) O3 during a high O3 month (June 2019) in Henan province in central China are explored using a source-oriented Community Multiscale Air Quality (CMAQ) model. The monthly average MDA8 O3 exceeds ∼70 ppb in more than half of the areas and shows a clear spatial gradient, with lower O3 concentrations in the southwest and higher in the northeast. Significant contributions of anthropogenic emissions to monthly average MDA8 O3 concentrations of more than 20 ppb are predicted in the provincial capital Zhengzhou, mostly due to emissions from the transportation sector (∼50%) and in the areas in the north and northeast regions where industrial and power generation-related emissions are high. Biogenic emissions in the region only contribute to approximately 1-3 ppb of monthly average MDA8 O3. In industrial areas north of the province, their contributions reach 5-7 ppb. Two CMAQ-based O3-NOx-VOCs sensitivity assessments (the local O3 sensitivity ratios based on the direct decoupled method and the production ratio of H2O2 to HNO3) and the satellite HCHO to NO2 column density ratio consistently show that most of the areas in Henan are in NOx-limited regime. In contrast, the high O3 concentration areas in the north and at the city centers are in the VOC-limited or transition regimes. The results from this study suggest that although reducing NOx emissions to reduce O3 pollution in the region is desired in most areas, VOC reductions must be applied to urban and industrial regions. Source apportionment simulations with and without Henan anthropogenic emissions show that the benefit of local anthropogenic NOx reduction might be lower than expected from the source apportionment results because the contributions of Henan background O3 increase in response to the reduced local anthropogenic emissions due to less NO titration. Thus, collaborative O3 controls in neighboring provinces are needed to reduce O3 pollution problems in Henan effectively.

[Evaluation of Changes in PM2.5 Exposure Concentration and Health Risk for Urban Resident in Zhengzhou Based on High Spatial Resolution Grids].

In recent years, complex air pollution with the characteristic pollutant of PM2.5 has remained serious in China. Long term exposure to PM2.5 might harm residential health and can increase premature death from specific diseases. The annual average concentration of PM2.5 in Zhengzhou was much higher than the national secondary standard, which has an extremely negative impact on the health of residents. Based on the high spatial resolution grids of population density established through web-crawling and outdoor monitoring concentrations and urban residential emissions used to evaluate PM2.5 exposure concentration, the exposure concentration of PM2.5 for urban residents of Zhengzhou was assessed, considering both indoor and outdoor exposures. Relevant health risks were quantified with the integrated exposure-response model. Finally, the contributions of various reducing measures and different standards of air quality to the decreases in PM2.5 exposure concentration were analyzed. The results showed that in 2017 and 2019, the time weighted exposure concentrations of PM2.5 for Zhengzhou's urban residents were 74.06 µg·m-3 and 60.64 µg·m-3, respectively, which was decreased by 18.12%. In addition, the mass fractions of the indoor exposure concentrations in the time weighted exposure concentrations were 83.58% and 83.01%, and its contribution to the drop of the time weighted exposure concentrations was 84.06%. In 2017 and 2019, the numbers of premature deaths attributed to PM2.5 exposures for urban residents of Zhengzhou over the age of 25 were 13285 and 10323, respectively, showing a 22.30% decrease. By using these comprehensive measures, PM2.5 exposure concentration for Zhengzhou's urban residents could be reduced by 86.23% at most, and 8902 premature deaths could be avoided.

[One-year Simulation of Air Pollution in Central China, Characteristics, Distribution, Inner Region Cross-transmission, and Pathway Research in 18 Cities].

Air pollution in Henan province is serious and is significantly impacted by pollution transmission and interactions with surrounding areas. The emission sources in 18 cities in Henan province were labeled and applied to the WRF-CMAQ traceability model for simulation in January, April, July, and October of 2017. The pollutant distribution results showed that due to the combined influence of emissions and meteorology, the concentrations of PM2.5, NO2, and SO2 in Henan province were the highest in winter and the lowest in summer. The seasonal variation in O3-8h concentration was the highest in summer, followed by spring, and the lowest in winter. There was a large difference in pollutant concentrations between different seasons. The average concentrations of PM2.5, NO2, and SO2 in winter in Henan province were 4.17, 4.12, and 6.24 times those in summer, respectively, whereas the concentration of O3-8h in summer was 2.24 times that in winter. Since PM2.5, NO2, and SO2 are closely related to primary emissions and have a certain homology, the distributions of high values of these three pollutants were higher in the north and lower in the south, and the seasonal trends were more consistent. The seasonal distribution of O3-8h varied widely, with high O3-8h values mainly distributed in the northeastern region of Henan province in summer, when meteorological conditions contributed to O3 production; in winter, spring, and autumn, high O3-8h values were mainly distributed in the southern part of Henan province due to the suppression of meteorological conditions and NOx consumption. The results of the study on the transport of pollutants showed that extra-provincial transport and natural sources contributed the most to the concentrations of PM2.5, O3-8h, NO2, and SO2 in winter, with 36.20%-72.32%, 77.96%-96.08%, 49.45%-78.80%, and 59.05%-88.85%, respectively. When considering only local emissions and intra-provincial transmission, the contributions of emissions to local concentrations of the four pollutants in summer were the highest in all cities of Henan province. The contributions of intra-provincial transmission to PM2.5 and O3-8h in spring were the largest, with 25.63%-74.69% and 30.21%-80.01%, respectively, and the contributions of intra-provincial transmission to NO2 and SO2 in winter were larger, with 26.02%-76.96% and 20.30%-82.34%. The transmission paths of PM2.5, NO2, and SO2 were more similar in Henan province, with more transmission from north to south in winter, from west to east and southwest to northeast in spring, from southwest to northeast in summer, and from north to south in autumn; however, the transmission of PM2.5 was more complicated. The O3-8h transport path was more different from the others, especially in autumn when pollutants were mostly transported from north to south, but the O3-8h transport path from southwest to northeast was obvious.

[Spatiotemporal Variations in Fine Particulate Matter and the Impact of Air Quality Control in Zhengzhou].

To study the spatiotemporal variations in fine particulate matter (PM2.5) and the impact of air quality management in autumn and winter in Zhengzhou, five sites were selected to collect PM2.5 samples from the autumn of 2017 to the winter of 2018, and the characteristics of the chemical components were analyzed. The positive matrix factorization (PMF) model was also applied to identify the sources of PM2.5, and the effect of air quality control was evaluated to provide support for air quality control in autumn and winter in the next stage. The PM2.5 concentrations in the four seasons in Zhengzhou were ranked as winter > autumn > spring > summer. The PM2.5 concentration at Zhengzhou University (ZZU) was the highest (8.7% higher than the average concentration), and the PM2.5 concentrations at the other sites were slightly lower than the average concentration. The concentration of water-soluble ions (WSIs) was low in spring and summer and high in autumn and winter. The average proportions of SO42-, NO3-, and NH4+ in the nine WSIs were as high as 22.5%, 43.6%, and 23.4%, respectively. The proportion of Cl- in winter was higher than that in the other seasons owing to coal combustion (6.7% and 6.6% in 2017 and 2018, respectively). Owing to wind and sand, the proportions of Ca2+ and Mg2+ in spring were the highest (4.4% and 0.4%, respectively), and those at the Jiancezhan (JCZ) and ZZU sites were higher than those at the other sites. K+, as a marker of biomass burning, had a higher proportion in spring, autumn, and winter. The proportion of K+ in the spring of 2018 was 1.9%, those in the autumn and winter of 2017 were 1.6% and 2.1%, respectively, and those in the autumn and winter of 2018 were 1.3% and 1.8%, respectively. JCZ, Hangkonggang (HKG), and Xinmi (XM) had higher proportions of NO3-, and the proportions of SO42- were lower. Secondary organic carbon (SOC) pollution was serious in autumn and winter, and the concentration accounted for more than half of the organic carbon (OC). In 2018, the SOC/OC at the JCZ and ZZU sites decreased compared with that in 2017, but that at the other three sites increased significantly, thereby indicating that different air pollutant emissions in these regions had different performances in response to control policies. The chemical composition reconstruction results showed that the proportion of sulfate was highest in summer (25.0%), the contribution of nitrate was higher in autumn (23.1% and 25.1% for 2017 and 2018, respectively) and winter (20.6% and 23.0% for 2017 and 2018, respectively), the proportion of crustal material was higher in spring (18.2%), and the contribution of secondary organic aerosol (SOA) was the highest in winter (14.1% and 20.5% for 2017 and 2018, respectively). SOA had higher contributions at the JCZ and HKG sites (16.9% and 16.4%, respectively), and ZZU was affected more by primary organic aerosol (14.3%) and crustal materials (12.1%). The PMF results showed that secondary inorganic salts (37.5%), SOA (15.4%), traffic (14.9%), industry (4.8%), coal combustion (16.0%), fugitive dust (6.5%), and biomass burning (2.8%) were the main pollution sources of PM2.5 in Zhengzhou. SOA and coal combustion contributed more in winter and fugitive dust contributed more in spring, followed by autumn. Biomass burning contributed more in spring and autumn. The urban sites JCZ and ZZU and the characteristic site HKG near the airport were more affected by traffic sources (16.9%, 16.2%, and 16.0%, respectively) than the other sites. The impact of biomass burning on the non-urban sites XM and HKG was slightly larger (both 2.7%), and the contribution of coal combustion to the suburban site XM was higher (16.8%). Owing to the construction around ZZU, the loading of fugitive dust at ZZU was higher than that at other sites. Comparing the results of the two-year autumn and winter, the contribution of SOA, traffic, and industry increased in the autumn and winter of 2018, whereas the contribution of secondary inorganic salts, coal combustion, and biomass burning decreased and the contribution of fugitive dust in winter also decreased. The results showed that the control strategies in autumn and winter had significant effects on the primary sources, including fugitive dust, coal combustion, and industry, and SOA precursor volatile organic compounds should be targeted for further pollution control.

[Health Impact Attributable to the Control of PM2.5 Pollution in China During 2013-2017].

To evaluate the health benefits brought about by air environmental treatment and determine the main drivers of health risk, we calculated the health and economic benefits attributed to PM2.5 control in Eastern and Central China from 2013 to 2017 by combining PM2.5 concentrations with a human activity enhanced exposure-response model. The relative contributions of changes in four factors related to the PM2.5 health burden were also quantified, namely total population, population aging, baseline mortality rates, and ambient exposure. The results show that the population weighted PM2.5 concentration decreased by 28.73% and the proportion of the population exposed to annual PM2.5 concentrations lower than or equal to 35 µg·m-3 increased from 11.23% to 27.91% across the study area during this period. Avoided deaths were decreased to 14.43%, which equates to avoided economic losses of approximately 559 billion RMB. If PM2.5 concentration meets the Chinese Ambient Air Quality Standard Grade Ⅱ (35 µg·m-3) or Grade Ⅰ (15 µg·m-3), or the World Health Organization Air Quality Guidelines (AQG) standards (10 µg·m-3), a 8.22%, 55.05%, and 79.36% reduction in the total deaths could be achieved in the base year (2017) with equivalent total economic benefits of approximately 319, 2137, and 3081 billion RMB, respectively. Total population, population aging, baseline mortality rates, and PM2.5 concentrations contributed -2.69%, -12.38%, 1.66%, and 14.57% to PM2.5-related deaths. Overall, during the study period, the reduction in PM2.5 concentrations has been the main factor contributing to the reduction in the public health burden. China has implemented significant air pollution control measures; however, the health burden associated with high PM2.5 concentrations in densely populated areas is still extremely high, requiring an aggressive air pollution control strategy.

Formation of droplet-mode secondary inorganic aerosol dominated the increased PM2.5 during both local and transport haze episodes in Zhengzhou, China.

The size distribution and formation of secondary inorganic aerosol play a key role in the increasing PM2.5 concentration. Size-segregated data including mass, number, and chemical component concentrations were obtained during a haze episode from January 12 to 23 in Zhengzhou to gain insight into the dominant factors for the growth of PM2.5. PM2.5 levels during two local processes (LP1 and LP2) were mainly affected by the accumulation and secondary formation of local pollutants. The transport process (TP) was affected by the air mass transported from the northern area of Zhengzhou. Results show that the growth of particle mass concentration in LP1 mainly occurred in the size range of 400-640 nm and 640-1000 nm. With the aggravated particles increases (LP2), 640-1000 nm and 1-1.6 µm particles dominated the increasing PM2.5 concentration. The particles carried by northern air mass (TP) were concentrated in the size range of 1-1.6 µm. Variation trends of hourly PM2.5 chemical components and size distribution of water-soluble inorganic ions suggested that the formation and growth of droplet-mode nitrate, sulfate, and ammonium dominated the increase of PM2.5, and the particle sizes of these components increased with the increasing PM2.5. High concentrations of aerosol water content and large surface area in droplet-mode were beneficial for the heterogeneous reactions for droplet-mode nitrate formation. Moreover, large particle surface area in droplet-mode particles also provided adequate carriers for the adsorption and condensation of gaseous HNO3 onto these particles. Elevated aerosol water, surface area, and particle acidity enhanced the H2O2 and transition metal (TMI) oxidation for aqueous-phase droplet-mode sulfate formation. The contribution of TMI-catalyzed oxidation significantly increased in LP2 because of the high TMI concentration and particle acidity. Relatively low aqueous-phase sulfate production rates in TP suggest that the observed high concentration of droplet-mode sulfate was mainly originated from the completely transformed SO42- carried by air masses. Moreover, droplet-mode particles exhibited moderate acidity, which enhanced the gas-particle partitioning of NH3(g)/NH4+(a).

[Evaluation of the Reduction in PM2.5 Concentration During the National Traditional Games of Ethnic Minorities in Zhengzhou].

To evaluate the effect of the implementation of emission reduction measures and the improvement in air quality during the National Traditional Games of Ethnic Minorities in Zhengzhou, a series of online instruments were used to continuously observe air pollutants and components of PM2.5 from August 5 to September 30, 2019. Three cases, including before emission reduction (August 5-24), during emission reduction (August 25 to September 18), and after emission reduction (September 19-30), were classified by the implementation of control measures. The results show that the growing concentration of PM2.5 after the cancellation of emission abatement measures (11.7 µg·m-3) was greater than that during the emission reduction (2.3 µg·m-3) compared to the PM2.5 concentration before emission reduction. This thus indicates that the control measures have a significant effect on reducing particulate matter. The main components of PM2.5 were organic matter, nitrate, ammonium, sulfate, and crustal elements. Compared to the proportion of components in PM2.5 before and during the control periods, organic matter and nitrate increased by 3.9% and 0.9%, respectively, while sulfate, ammonium, and crustal elements decreased by 1.1%, 1.9%, and 2.2%, respectively. The results of source appointment by positive matrix factorization show that secondary sulfate, secondary nitrate, secondary organic aerosols, vehicular emissions, industrial emissions, dust, and coal combustion are the main sources of PM2.5. Emission abatement measures reduced the contributions of primary sources such as dust, coal combustion, and industry by 8.3%, 8.2%, and 8.1%, respectively. In contrast, the contributions of secondary organic and nitrate aerosols increased during the control periods, which suggested that the control measures implemented in Zhengzhou had a weaker emission reduction effect on nitrogen oxide and volatile organic compounds than on primary sources of PM2.5.

Spatiotemporal characterization and regional contributions of O3 and NO2: An investigation of two years of monitoring data in Henan, China.

To investigate the characteristics of ground level ozone (O3) for Henan Province, the ambient air quality monitoring data of 2015 and 2016 were analyzed. The result showed that the 8 h-max-O3 concentrations displayed a distinct seasonality, where the maximum and minimum values, averaging 140.41, 54.19 µg/m3, occurred in summer and winter, respectively. There is a significant correlation between meteorological factors and O3 concentration. The Voronoi neighborhood averaging analysis indicated that O3, temperature, and ultraviolet radiation in Henan province were decreased from northwest to southeast, while relative humidity and precipitation displayed the opposite trend. Besides meteorological factors, the chemical processes play an essential role in ozone formation. Reactions of NO, NO2 and O3 form a closed system, and the partitioning point of the OX-component (O3 + NO2) was at 40 and 80 µg/m3 for nitrogen oxide (NOX) in winter and summer, respectively, with NO2 dominating at higher NOx pollution and O3 being the major component at lower levels. The relationship between oxidant (OX = O3+NO2) and NOx concentrations were evaluated to understand the regional and local contribution of OX. It showed that high regional contribution occurred in the spring, whereas the highest local contribution lead to the summer peak of O3 observed in Zhengzhou. This present study reveals important environment impacts from the photochemical process and the meteorological conditions in the region with better understanding on the O3 characterization.

Observation of chemical components of PM2.5 and secondary inorganic aerosol formation during haze and sandy haze days in Zhengzhou, China.

Mineral dust particles play an important role in the formation of secondary inorganic aerosols, which largely contribute to haze pollution in China. During this study, a haze episode (haze days) and a typical haze process mixed with sandstorm (sandy haze days) were observed in Zhengzhou with a series of high-time-resolution monitoring instruments from November 22 to December 8, 2018. Concentrations of PM10 and crustal elements clearly increased in the sandy haze days. Concentrations of gaseous pollutants, metallic elements emitted from anthropogenic sources, nitrate, and ammonium during sandy haze days were slightly lower than those during the haze days but still obviously higher than those during the non-haze days. The sulfate concentrations, the sulfate fractions in PM2.5, and the sulfur oxidation ratios significantly increased in the sandy haze days. Heterogeneous reactions dominated the conversion of SO2 during the haze and sandy haze days. Enhanced SO2 conversion during the sandy haze days may be attributed to the high concentrations of transition metal ions from the sandstorm when the values of relative humidity (RH) were in 30%-70%, and high O3 at certain time points. Gas-phase NO2 oxidation reactions were the main pathways for nitrate formation. In the sandy haze days, higher nitrogen oxidation ratio (NOR) at daytime may be associated with higher RH and lower temperature than those in the haze days, which facilitate the gas-to-particle partitioning of nitrate; higher NOR values at night may be attributed to the higher O3 concentrations, which promoted the formation of N2O5.

[Characteristic of Surface Ozone and Meteorological Parameters Analysis in Anyang City].

This study uses the national ambient air quality station data of Anyang City from 2014 to 2017 to analyze the characteristics and variation rules of ozone (O3) in different functional zones (urban, suburban, and industrial), and also studies meteorological influencing factors and potential source distributions of O3 pollution. The results showed that the O3 concentration in Anyang increased significantly between 2014 and 2017, whereby pollution started to advance from 2015 and the earliest occurrence of an O3 pollution episode was in April 2017. The 90th percentile and average concentrations of O3 in the industrial zone increased at faster rates (average annual growth of 16.0 µg·m-3 and 13.0 µg·m-3, respectively) than of those in the urban and suburban zones. The O3 concentrations at the suburban site showed the fastest increase of all zones at the 5th percentile (average annual growth of 13.2 µg·m-3). The monthly variation in O3 concentrations in Anyang showed an "M" pattern that varied spatially depending on the zone. Temperature played a leading role in O3 concentrations; air temperatures >23℃, relative humidity <58%, and a wind speed of 5 m·s-1 in a south-southwesterly direction were closely related to the occurrence of high O3 concentrations. Potential sources of O3 in different seasons were significantly different, and mainly distributed in southern Hebei, northern Hubei, and northern Shenyang in summer. The first heavy O3 pollution day in the studied period was in May 2017, at which time the highest O3 concentration was found in the industrial zone (up to 405 µg·m-3). This heavy O3 pollution episode was related to the continuous high temperature that was caused by the transfer of a dry, hot air mass in western China.

Chemical characteristics and source apportionment of PM2.5 between heavily polluted days and other days in Zhengzhou, China.

PM2.5 samples were collected in Zhengzhou during 3years of observation, and chemical characteristics and source contribution were analyzed. Approximately 96% of the daily PM2.5 concentrations and annual average values exceeded the Chinese National Ambient Air Quality Daily and Annual Standards, indicating serious PM2.5 pollution. The average concentration of water-soluble inorganic ions was 2.4 times higher in heavily polluted days (daily PM2.5 concentrations>250µg/m3 and visibility <3km) than that in other days, with sulfate, nitrate, and ammonium as major ions. According to the ratio of NO3-/SO42-, stationary sources are still the dominant source of PM2.5 and vehicle emission could not be ignored. The ratio of secondary organic carbon to organic carbon indicated that photochemical reactivity in heavily polluted days was more intense than in other days. Crustal elements were the most abundant elements, accounting for more than 60% of 23 elements. Chemical Mass Balance results indicated that the contributions of major sources (i.e., nitrate, sulfate, biomass, carbon and refractory material, coal combustion, soil dust, vehicle, and industry) of PM2.5 were 13%, 16%, 12%, 2%, 14%, 8%, 7%, and 8% in heavily polluted days and 20%, 18%, 9%, 2%, 27%, 14%, 15%, and 9% in other days, respectively. Extensive combustion activities were the main sources of polycyclic aromatic hydrocarbons during the episode (Jan 1-9, 2015) and the total benzo[a]pyrene equivalency concentrations in heavily polluted days present significant health threat. Because of the effect of regional transport, the pollution level of PM2.5 in the study area was aggravated.

Gender impacts on the correlations between nonalcoholic fatty liver disease and hypertension in a Chinese population aged 45-60 y.

No previous study has reported the association between nonalcoholic fatty liver disease (NAFLD) and the risk of hypertension in the Chinese population. Therefore, the aim of this study was to evaluate the relationship between NAFLD and hypertension in a middle-aged Chinese population. The study subject was (a group of) 1006 Chinese adults aged 45-60 y in Shandong Province who participated in the Weifang Nutrition and Health Survey (2014-2015). Hypertension was defined as systolic blood pressure (SBP) ≥140 mmHg or diastolic blood pressure (DBP) ≥ 9 0mmHg. NAFLD was defined as the presence of moderate-severe hepatic steatosis (by B-ultrasonic examination), the absence of excessive alcohol use (>20 g/d in men and 10 g/d in women), no use of steatogenic medications within the past six months, no exposure to hepatotoxins, and no history of bariatric surgery. All anthropometric measurements and biochemical data were collected following standard protocols. Multivariate logistic regression analysis was used to identify the association between NAFLD and hypertension with adjustment of potential confounding variables. Body mass index (BMI), waist circumference (WC), waist-to-hip ratio (WHR), fasting glucose, SBP, DBP, triglycerides (TG), serum uric acid (SUA), alanine aminotransferase (ALT), aspartate aminotransferase (AST), and the prevalence of hypertension and NAFLD were significantly higher in males than in females (p < 0.05). Females had significantly higher levels of total cholesterol (TC) and high-density lipoprotein cholesterol (HDL-C). After adjusting for potential confounders, NAFLD was associated with an increased risk of hypertension in both male and female, with odds ratios (ORs) (95% CI) of 2.152 (1.324-3.498) and 2.133 (1.409-3.229), respectively. CONCLUSIONS: Our findings indicated that NAFLD was significantly associated with the risk of hypertension in males than in females. However, our findings also need to be confirmed in future prospective studies. ABBREVIATIONS: BMI: body mass index; WC: waist circumference; WHR: waist-hip ratio; SBP: systolic blood pressure; DBP: diastolic blood pressure; FG: fasting glucose; TG: triglycerides; TC: total cholesterol; HDL-C: high-density lipoprotein cholesterol; SUA: serum uric acid; NAFLD: nonalcoholic fatty liver disease; LDL-C: low-density lipoprotein cholesterol; OR: odds ratio; CI: confidence interval; ALT: alanine aminotransferase; AST: aspartate aminotransferase.

Atorvastatin Treatment for Atrial Fibrillation Reduces Serum High-Sensitivity C-Reactive Protein Levels.

We investigated whether serum hs-CRP levels predict the efficacy of atrial fibrillation (AF) treated with atorvastatin. Bibliographic databases were exhaustively searched for studies relevant to the research topic. Newcastle-Ottawa Scale (NOS) criteria, combined with the Quality Assessment of Diagnostic Accuracy Studies (QUADAS), were applied for study quality assessment. Our meta-analysis identified seven cohort studies (2006~2013), providing information on the change in serum hs-CRP levels in AF patients receiving atorvastatin therapy. After atorvastatin treatment, hs-CRP level in AF patients decreased significantly (SMD = 1.02, 95% CI: 0.58-1.47, P < 0.001). Subgroup analysis by country and hs-CRP detection methods suggested a negative relationship between atorvastatin treatment and hs-CRP levels among Chinese AF patients (SMD = 1.34, 95% CI: 1.00-1.69, P < 0.001) and by using ELISA method (SMD = 1.11, 95% CI: 0.51-1.71, P < 0.001), but not among Turkish population and using INA method (all P > 0.05). Egger's test showed no publication bias (P = 0.450). hs-CRP was clearly lowered in AF patients treated with atorvastatin, which may be helpful in the choice of statin agents for AF treatment. However, longer follow-ups are necessary to assess the clinical value of lowering hs-CRP in the clinical setting of AF treatment outcomes.

Transforming growth factor ß-interacting factor-induced malignant progression of hepatocellular carcinoma cells depends on superoxide production from Nox4.

Hepatocellular carcinoma (HCC) is one of the most deadly malignancies worldwide because of its high recurrence rate, high metastatic potential, and resistance to drugs. Elucidation of the mechanisms underlying malignancy in HCC is needed to improve diagnosis, therapy, and prognosis. Previously, we showed that transforming growth factor ß-interacting factor (TGIF) antagonizes arsenic trioxide-induced apoptosis of HepG2 cells and is associated with poor prognosis and progression of urothelial carcinoma in patients after radical nephroureterectomy. To determine whether TGIF plays a role in HCC tumorigenesis, we compared the expression of TGIF, its downstream targets, and reactive oxygen species levels between HCC HepG2 cells and the more invasive SK-Hep1 cells. Superoxide production, phosphorylation of c-Src(Y416) and AKT(S473), and expression of TGIF and NADPH oxidase (Nox) were higher in invasive SK-Hep1 cells than in HepG2 cells. TGIF-overexpressing HepG2 xenograft tumors markedly promoted tumor growth and metastasis to the lungs. Overexpression of TGIF in HepG2 cells increased superoxide production from Nox4, matrix metalloproteinase expression, invadopodia formation, and cellular migration/invasion ability. Conversely, knockdown of TGIF in SK-Hep1 cells attenuated these processes. Using gene knockdown and pharmacological inhibitors, we demonstrate that c-Src/AKT is the upstream signaling that regulates TGIF-induced Nox4 activation and subsequent superoxide production. Taken together, our results implicate TGIF as a potential biomarker for prognosis and target for clinical therapy in patients with advanced HCC.

Involvement of TG-interacting factor in microglial activation during experimental traumatic brain injury.

Traumatic brain injury (TBI) is a complex injury involving several physiological alterations, potentially leading to neurological impairment. Previous mouse studies using high-density oligonucleotide array analysis have confirmed the upregulation of transforming growth-interacting factor (TGIF) mRNA in TBI. TGIF is a transcriptional corepressor of transforming growth factor beta (TGF-ß) signaling which plays a protective role in TBI. However, the functional roles of TGIF in TBI are not well understood. In this study, we used confocal microscopy after immunofluorescence staining to demonstrate the increase of TGIF levels in the activated microglia of the pericontusional cortex of rats with TBI. Intracerebral knockdown of TGIF in the pericontusional cortex significantly downregulated TGIF expression, attenuated microglial activation, reduced the volume of damaged brain tissue, and facilitated recovery of limb motor function. Collectively, our results indicate that TGIF is involved in TBI-induced microglial activation, resulting in secondary brain injury and motor dysfunction. This study investigated the roles of transforming growth-interacting factor (TGIF) in a traumatic brain injury (TBI)-rat model. We demonstrated the increase of TGIF levels in the activated microglia of the pericontusional cortex of rats with TBI. Intracerebral knockdown of TGIF in the pericontusional cortex of the TBI rats significantly attenuated micoglial activation, reduced the volume of damaged brain tissue, and facilitated recovery of limb motor function. We suggest that inhibition of TGIF might provide a promising therapeutic strategy for TBI.

Effects of acute mechanical stretch on the expression of mechanosensitive potassium channel TREK-1 in rat left ventricle.

To explore the role of mechanosensitive potassium channel TREK-1, Western blot analysis was used to investigate the expression changes of TREK-1 in left ventricle in acute mechanically stretched heart. Forty Wistar rats were randomly divided into 8 groups (n=5 in each group), subject to single Langendorff perfusion for 0, 30, 60, 120 min and acute mechanical stretch for 0, 30, 60, 120 min respectively. With Langendorff apparatus, an acute mechanically stretched heart model was established. There was no significant difference in the expression of TREK-1 among single Langendorff perfusion groups (P>0.05). As compared to non-stretched Langendorff-perfused heart, only the expression of TREK-1 in acute mechanically stretched heart (120 min) was greatly increased (P<0.05). This result suggested that some course of mechanical stretch could up-regulate the expression of TREK-1 in left ventricle. TREK-1 might play an important role in mechanoelectric feedback, so it could reduce the occurrence of arrhythmia that was induced by extra mechanical stretch.