Bone morphogenetic protein-2 and pulsed electrical stimulation synergistically promoted osteogenic differentiation on MC-3T3-E1 cells.

Electrical stimulation (ES) plays an important role in regulating cell osteoblast differentiation. As a noninvasive rehabilitation therapy method, Es has a unique role in postoperative recovery. Bone morphogenetic protein-2 (BMP-2) is the most commonly used bioactive molecule in in situ tissue engineering scaffolds, and it plays an important regulatory role in the whole process of bone injury repair. In this study, the osteogenic regulation of MC-3T3-E1 cells was studied by combining pulsed electrical stimulation (PES) and different concentrations of BMP-2. The results showed that PES and BMP-2 could synergically promote the proliferation of MC-3T3-E1 cells. The qPCR results of osteoblast-related genes showed that PES was synergistic with BMP-2 to promote osteoblast differentiation mainly through the regulation of the Smad/BMP and insulin like growth factor 1 (IGF1) signaling pathways. The expression level of alkaline phosphatase (ALP) and alizarin red staining further demonstrated the synergistic effect of PES and BMP-2 on promoting osteogenic differentiation and mineralization of cells. PES and BMP-2 could also synergically promote cell proliferation, expression of collagen I (COL-I) and ALP, and cell mineralization on the 3D-printed polylactic acid scaffold. These results suggest that the use of PES can enhance the osteogenic effect of in situ bone repair scaffolds containing BMP-2, reduce the dose of BMP-2 alone, and reduce the possible side effects of high-dose BMP-2 in vivo.

Localized biogenic volatile organic compound emission inventory in China: A comprehensive review.

Volatile organic compounds (VOCs) are the precursors of forming ozone (O3) and fine particulate matter (PM2.5). Accurate estimates of biogenic VOC (BVOC) emissions is essential for understanding the formation mechanism of O3 and PM2.5 pollution and precise reduction on anthropogenic emissions and thereby mitigating O3 and PM2.5 pollution. To gain comprehensive knowledge of BVOC emissions and improve the accuracy of their estimation, this study reviewed localized national, regional, and municipal emission estimations in China. From their comparisons, BVOC emission characteristics and deficiencies in the inventory compilation methodology were also investigated. The estimated BVOC emissions in China ranged between 10 and 58.9 Tg yr-1 and 10.9-18.9 Tg C yr-1, with diverse contributions for different BVOC categories. The simulated historical and future BVOC emissions exhibited an increasing trend. The uncertainty of the BVOC estimates was mainly from the applications of incomplete emission models, less localized accurate emission factors, deficient vegetation cover information, and low-resolution meteorological data in the inventory compilation. The regional and municipal BVOC emission inventories mainly focused on the Beijing-Tianjin-Hebei, Pearl River Delta, Sichuan Basin, and Yangtze River Delta regions, as well as the cities therein. For the same area, different studies reported diverse BVOC emissions by a maximum of two orders of magnitude. There is usually a lack of basic data with more detailed investigations and higher precision for estimation of BVOC emissions. By summarizing the measurements on terrestrial and marine BVOC emission fluxes, they are mainly focused on the Guangdong, Zhejiang and Jiangxi provinces, and Yellow Sea, East China Sea, and South China Sea, respectively. Expanding the temporal and spatial scales of observations is encouraged to enhance our understanding on the emissions and improve the emission estimates.

Impacts of synoptic circulation on surface ozone pollution in a coastal eco-city in Southeastern China during 2014-2019.

The coastal eco-city of Fuzhou in Southeastern China has experienced severe ozone (O3) episodes at times in recent years. In this study, three typical synoptic circulations types (CTs) that influenced more than 80% of O3 polluted days in Fuzhou during 2014-2019 were identified using a subjective approach. The characteristics of meteorological conditions linked to photochemical formation and transport of O3 under the three CTs were summarized. Comprehensive Air Quality Model with extensions was applied to simulate O3 episodes and to quantify O3 sources from different regions in Fuzhou. When Fuzhou was located to the west of a high-pressure system (classified as "East-ridge"), more warm southwesterly currents flowed to Fuzhou, and the effects of cross-regional transport from Guangdong province and high local production promoted the occurrence of O3 episodes. Under a uniform pressure field with a low-pressure system occurring to the east of Fuzhou (defined as "East-low"), stagnant weather conditions caused the strongest local production of O3 in the atmospheric boundary layer. Controlled by high-pressure systems over the mainland (categorized as "Inland-high"), northerly airflows enhanced the contribution of cross-regional transport to O3 in Fuzhou. The abnormal increases of the "East-ridge" and "Inland-high" were closely related to O3 pollution in Fuzhou in April and May 2018, resulting in the annual maximum number of O3 polluted days during recent years. Furthermore, the rising number of autumn O3 episodes in 2017-2019 was mainly related to the "Inland-high", indicating the aggravation of cross-regional transport and highlighting the necessity of enhanced regional collaboration and efforts in combating O3 pollution.

Isoprenoid emissions from natural vegetation increased rapidly in eastern China.

An accurate local biogenic volatile organic compound (BVOC) emission inventory in Shandong Province is crucial for air pollution control in Shandong and the Beijing-Tianjin-Hebei region, China. We estimated the multi-year isoprenoid emissions from natural vegetation in Shandong Province at a spatial resolution of 4 km × 4 km using the MEGAN2.1 model. A new vegetation classification with 23 plant species/types was developed, and emission factors were determined based on the most detailed and localized investigation and statistics. Isoprene, monoterpene, and sesquiterpene emissions in 2018 were 325.6, 18.2, and 7.9 Gg (mass of carbon), respectively. ß-Pinene, α-pinene, ocimene, farnescene, and caryophyllene were the dominant monoterpenes and sesquiterpenes. Broadleaf trees contributed the most to total emissions, particularly poplar, which had the highest emission rates. Wheat also had higher emissions owing to its large coverage. Isoprenoid emissions displayed an inverted "U" pattern when plotted against the months and peaked in summer. Emissions were concentrated in the western and southeastern areas with emission intensities of >10 ton/grid, including Dezhou, Liaocheng, and Rizhao cities. During 1981-2018, isoprenoid emissions experienced a rapid increase from 12.0 to 351.7 Gg, at a rate of 11.20 Gg/yr. Isoprene had the highest enhancement rate of 10.72 Gg/yr. The most rapid increase was observed in the northwestern cities Dezhou and Liaocheng, and the southeastern cities Rizhao, at an average rate of >100 kg/yr, even >500 kg/yr in some areas. The high emissions and their continued increase should be considered when studying the prevention and control of regional air pollution and making policies in China.

Temporal and spatial distribution characteristics and source origins of volatile organic compounds in a megacity of Sichuan Basin, China.

As important pollution gases and represented precursors of both ozone and second organic aerosol (SOA), the component characteristics, source origins, environmental health and emission control of volatile organic compounds (VOCs), are gaining more and more attention in Chinese megacities. In order to understand the concentration, composition and temporal and spatial distribution characteristics of VOCs in the atmosphere of Chengdu, a megacity located in Sichuan basin in southwest China, the offline sampling measurements of VOCs were carried out at 28 different field sites covering all the districts and counties of Chengdu during special periods from May 2016 to January 2017. Speciated VOCs measurement was performed by the GC-FID/MS, and 99 species were identified. The averaged total VOC mixing ratios of each sampling site were in the range from 35.03 to 180.57 ppbv. Based on these observational data, the distribution characteristics of VOCs in different months and different regions of Chengdu were clarified. The VOCs data were used to estimate the potential amount of ozone, secondary aerosol formation and health risk assessment in Chengdu. Furthermore, the positive matrix factorization (PMF) model was used to identify the dominant emission sources and evaluate their contribution to VOCs in the city. The two main sources of VOCs in Chengdu were motor vehicle exhaust and solvent utilization. These accounted for 43% of all emission sources. In the summertime, due to higher temperatures and stronger sunlight, the contribution of natural sources and secondary emissions were also relatively high, which were supported by the regional emission inventories. Finally, the controlling direction of VOCs and O3 pollution in Chengdu was discussed, and the VOCs pollution control strategy was proposed for the near future.

Characteristics of volatile organic compounds, NO2, and effects on ozone formation at a site with high ozone level in Chengdu.

Chengdu is a megacity in the southwest of China with high ozone (O3) mixing ratio. Observation of volatile organic compounds (VOCs), NO2 and O3 with high temporal resolution was conducted in Chengdu to investigate the chemical processes and causes of high O3 levels. The hourly mixing ratios of VOCs, NO2, and O3 were monitored by an online system from 28 August to 7 October, 2016. According to meteorological conditions, Chengdu, with relative warm weather and low wind speed, is favorable to O3 formation. Part of the O3 in Chengdu may be transported from the downtown area. In O3 episodes, the average mixing ratios of NO2 and O3 were 20.20 ppbv and 47.95 ppbv, respectively. In non-O3 episodes, the average mixing ratios of NO2 and O3 were 16.38 ppbv and 35.15 ppbv, respectively. The average mixing ratio of total VOCs (TVOCs) was 40.29 ppbv in non-O3 episodes, which was lower than that in O3 episodes (53.19 ppbv). Alkenes comprised 51.7% of the total O3 formation potential (OFP) in Chengdu, followed by aromatics which accounted for 24.2%. Ethylene, trans-pentene, propene, and BTEX (benzene, ethylbenzene, toluene, m/p-xylene, o-xylene) were also major contributors to the OFP in Chengdu. In O3 episodes, intensive secondary formations were observed during the campaign. Oxygenated VOCs (OVOCs), such as acetone, Methylethylketone (MEK), and Methylvinylketone (MVK) were abundant. Isoprene rapidly converted to MVK and Methacrolein (MACR) during O3 episodes. Acetone was mainly the oxidant of C3-C5 hydrocarbons.

Spatial Distribution of Secondary Organic Aerosol Formation Potential in China Derived from Speciated Anthropogenic Volatile Organic Compound Emissions.

Fine particulate matter (PM2.5), largely composed of secondary organic aerosol (SOA), is currently one of the most intractable environmental problems in China. As crucial precursors for SOA, understanding the formation propensity of various volatile organic compound (VOC) species and sources is useful for pollution control. In this work, we estimated the SOA formation potential (SOAP) of anthropogenic VOC emissions based on an improved speciated VOC emission inventory and investigated its distribution in China. According to our estimates, toluene had the largest SOAP, followed by n-dodecane, m-/p-xylene, styrene, n-decane, and n-undecane, while passenger cars, chemical fiber manufacturing, asphalt paving, and building coating were the top five SOAP-contributing sources nationwide. The spatial distribution of SOAP in China shows a distinct pattern of high values in the southeast and low values in the northwest. Beijing-Tianjin-Hebei and surroundings, the Yangtze River Delta, Pearl River Delta, and Sichuan-Chongqing District were found to have the highest SOAP, particularly in urban areas. The major SOAP-contributing species and sources differed among these regions, which was attributed to local industrial and energy structures. Our results suggest that to mitigate PM2.5 pollution in China, more efficient SOAP-based control measures should be implemented instead of current emissions-based policies, and VOC control strategies should be adapted to local conditions.

Spatial Distribution of Ozone Formation in China Derived from Emissions of Speciated Volatile Organic Compounds.

Ozone (O3) pollution is becoming increasingly severe in China. In addition, our limited understanding of the relationship between O3 and volatile organic compounds (VOCs), is an obstacle to improving air quality. By developing an improved source-oriented speciated VOC emission inventory in 2013, we estimated the ozone formation potential (OFP) and investigated its characteristics in China. Besides, a comparison was made between our estimates and space-based observations from the ozone monitoring instrument (OMI) on the National Aeronautics and Space Administration (NASA)'s Aura satellite. According to our estimates, m-/p-xylene, ethylene, formaldehyde, toluene, and propene were the five species that had the largest potential to form ozone, and on-road vehicles, industrial processes, biofuel combustion, and surface coating were the key contributing sectors. Among different regions of China, the North China Plain, Yangtze River Delta, and Pearl River Delta had the highest OFP values. Our results suggest that O3 formation is VOC-limited in major urban areas of China. Additionally, considering the different photochemical reactivities of various VOC species and the disparate energy and industry structures in the different regions of China, more efficient OFP-based and localized VOC control measures should be implemented, instead of the current mass-based and nationally uniform policies.

Estimating emissions from crop residue open burning in China based on statistics and MODIS fire products.

With the objective of reducing the large uncertainties in the estimations of emissions from crop residue open burning, an improved method for establishing emission inventories of crop residue open burning at a high spatial resolution of 0.25°×0.25° and a temporal resolution of 1month was established based on the moderate resolution imaging spectroradiometer (MODIS) Thermal Anomalies/Fire Daily Level3 Global Product (MOD/MYD14A1). Agriculture mechanization ratios and regional crop-specific grain-to-straw ratios were introduced to improve the accuracy of related activity data. Locally observed emission factors were used to calculate the primary pollutant emissions. MODIS satellite data were modified by combining them with county-level agricultural statistical data, which reduced the influence of missing fire counts caused by their small size and cloud cover. The annual emissions of CO2, CO, CH4, nonmethane volatile organic compounds (NMVOCs), N2O, NOx, NH3, SO2, fine particles (PM2.5), organic carbon (OC), and black carbon (BC) were 150.40, 6.70, 0.51, 0.88, 0.01, 0.13, 0.07, 0.43, 1.09, 0.34, and 0.06Tg, respectively, in 2012. Crop residue open burning emissions displayed typical seasonal and spatial variation. The highest emission regions were the Yellow-Huai River and Yangtse-Huai River areas, and the monthly emissions were highest in June (37%). Uncertainties in the emission estimates, measured as 95% confidence intervals, range from a low of within ±126% for N2O to a high of within ±169% for NH3.

Emission factors and source profiles of volatile organic compounds in container manufacturing industry.

The container manufacturing industry is the key contributor of industrial volatile organic compounds (VOCs). Emission factors (EFs) and source profiles of container manufacturing industry were comprehensively investigated basing on multiple VOCs discharge links. 17 samples were collected from a typical container manufacturing enterprise based on field measurements. The material balance method and weighted average method were applied to estimate EFs and establish VOCs source profiles. It is found that diluent use (DU) was the largest contributor (39.96 %), followed by intermediate painting spaying (IMPS), primer painting (PP), chassis painting (CP), exterior paint spaying (EPS), and interior paint spaying (IPS). EF of the container manufacturing industry (2.90 kg VOCs/ Twenty-foot Equivalent Units, TEU) was firstly estimated. EFs of six processes were further estimated. The EFs of DU, IMPS, PP, CP, EPS, and IPS were 1.22, 0.74, 0.42, 0.33, 0.20, and 0.00045 kg VOCs/TEU, respectively. EFs of six materials were further estimated. The EF of the diluent was largest (382.74 kg VOCs/t material), followed by water-based epoxy intermediate paint (132.09 kg VOCs/t material), organic-based epoxy zinc-rich priming paint (91.31 kg VOCs/t material). EFs of other paints ranged from 0.0047 to 43.01 kg VOCs/t material. These results suggest that the replacement of lower- VOCs- contained diluent and effective control from diluent consumption are dramatically conducive to VOCs reduction. Source profiles were established at the industry and individual process levels. Aromatics (77.05-98.38 %) were dominant components in all processes, followed by alkane and OVOCs. m/p-Xylene, o-xylene, and ethylbenzene were the key active species that should be prioritized for control. Overall, EFs and source profiles of the container manufacturing industry were firstly proposed, conducing to the systematic formulation of VOCs control strategies.

Emission factors and source profiles of volatile organic compounds from the automobile manufacturing industry.

Controlling volatile organic compounds (VOCs) emitted from the automobile manufacturing industry requires establishing VOCs emission factors (EFs) and source profiles refinedly. In this study, 41 samples involved 32 VOCs discharge links were collected from three factories. The EFs and VOCs source profiles were estimated by the material balance method and weighted average method, respectively. The ozone formation potential (OFP) of the 110 VOCs species were calculated by the maximum incremental reactivity (MIR). According to estimations, the ranges of EFs were 0.23-1.66 kg VOCs/SUV car and 2.14-14.86 g VOCs/m2 painted area. EFs of six materials were firstly estimated, which are electrophoretic primer (152.31 ± 97.39 g VOCs/SUV car, 0.97 ± 0.38 g VOCs/m2 painted area), sealant (48.39 ± 26.20 g VOCs/SUV car, 0.46 ± 0.25 g VOCs/m2 painted area), floating coat (87.40 ± 75.63 g VOCs/SUV car, 0.86 ± 0.74 g VOCs/m2 painted area), colored paint (127.24 ± 168.24 g VOCs/SUV car, 1.25 ± 1.66 g VOCs/m2 painted area), varnish (205.46 ± 218.14 g VOCs/SUV car, 2.01 ± 2.15 g VOCs/m2 painted area), and cleaning solvent (328.54 ± 404.94 g VOCs/SUV car, 3.23 ± 3.98 g VOCs/m2 painted area). OVOCs (37.40-51.60 %) and aromatics (36.40-37.00 %) were the dominant components. n-Butyl acetate, 1,2,4-trimethylbenzene, undecane, n-hexanal, acetone, 1,2,3-trimethylbenzene, 1,3,5 -trimethylbenzene, m/p/o-xylene, 3-ethylbenzene, and 4-ethylbenzene were the major VOCs species, accounting for 68 % of total VOCs in the automobile manufacturing industry. Considering the OFP values of species, 1,2,4-trimethylbenzene, 1,3,5-trimethylbenzene, 1,2,3-trimethylbenzene, m/p-xylene, acetaldehyde, methyl ethyl ketone are the key active species that should be prioritized for control.

PM2.5 constituents associated with childhood obesity and larger BMI growth trajectory: A 14-year longitudinal study.

BACKGROUND: The association of specific PM2.5 chemical constituents with childhood overweight or obesity (OWOB) remain unclear. Furthermore, the long-term impacts of PM2.5 exposure on the trajectory of children's body mass index (BMI) have not been explored. METHODS: We conducted a longitudinal study among 1,450,830 Chinese children aged 6-19 years from Beijing and Zhongshan in China during 2005-2018 to examine the associations of PM2.5 and its chemical constituents with incident OWOB risk. We extracted PM2.5 mass and five main component exposure from Tracking Air Pollution in China (TAP) dataset. Cox proportional hazards models were applied to quantify exposure-response associations. We further performed principal component analysis (PCA) to handle the multi-collinearity and used quantile g-computation (QGC) approach to analyze the impacts of exposure mixtures. Additionally, we selected 125,863 children with at least 8 physical examination measurements and combined group-based trajectory models (GBTM) with multinomial logistic regression models to explore the impacts of exposure to PM2.5 mass and five constituents on BMI and BMI Z-score trajectories during 6-19 years. RESULTS: We observed each interquartile range increment in PM2.5 exposure was significantly associated with a 5.1 % increase in the risk of incident OWOB (95 % confidence Interval [CI]: 1.036-1.066). We also found black carbon, sulfate, organic matter, often linked to fossil combustion, had comparable or larger estimates of the effect (HR = 1.139-1.153) than PM2.5. Furthermore, Exposure to PM2.5 mass, sulfate, nitrate, ammonium, organic matter and black carbon was significantly associated with an increased odds of being in a larger BMI trajectory and being assigned to persistent OWOB trajectory. CONCLUSIONS: Our findings provide evidence that the constituents mainly from fossil fuel combustion may have a perceptible influence on increased OWOB risk associated with PM2.5 exposure in China. Moreover, long-term exposure to PM2.5 contributes to an increased odds of being in a lager BMI and a persistent OWOB trajectories.

Ozone sensitivity regimes vary at different heights in the planetary boundary layer.

The sensitivity of tropospheric ozone (O3) to its precursors volatile organic compounds (VOCs) and nitrogen oxides (NOX) determines the emission reduction strategy for O3 mitigation. Due to the lack of comprehensive vertical measurements of VOCs, the vertical distribution of O3 sensitivity regimes has not been well understood. O3 precursor sensitivity determined by ground-level measurements has been generally used to guide O3 control strategy. Here, to precisely diagnose O3 sensitivity regimes at different heights in the planetary boundary layer (PBL), we developed a vertical measurement system based on an unmanned aerial vehicle platform to conduct comprehensive vertical measurements of VOCs, NOX and other relevant parameters. Our results suggest that the O3 precursor sensitivity shifts from a VOC-limited regime at the ground to a NOX-limited regime at upper layers, indicating that the ground-level O3 sensitivity cannot represent the situation of the whole PBL. We also found that the state-of-the-art photochemical model tends to underestimate oxygenated VOCs at upper layers, resulting in overestimation of the degree of VOCs-limited regime. Therefore, thorough vertical measurements of VOCs to accurately diagnose O3 precursor sensitivity is in urgent need for the development of effective O3 control strategies.

Temporal and spatial variation in recent vehicular emission inventories in China based on dynamic emission factors.

UNLABELLED: The vehicular emission trend in China was tracked for the recent period 2006-2009 based on a database of dynamic emission factors of CO, nonmethane volatile organic compounds (NMVOC), NOx, PM10, CO2, CH4, and N2O for all categories of on-road motor vehicles in China, which was developed at the provincial level using the COPERT 4 model, to account for the effects of rapid advances in engine technologies, implementation of improved emission standards, emission deterioration due to mileage, and fuel quality improvement. Results show that growth rates of CO and NMVOC emissions slowed down, but NOx and PM10 emissions continued rising rapidly for the period 2006-2009. Moreover CO2, CH4, and N2O emissions in 2009 almost doubled compared to those in 2005. Characteristics of recent spatial distribution of emissions and emission contributions by vehicle category revealed that priority of vehicular emission control should be put on the eastern and southeastern coastal provinces and northern regions, and passenger cars and motorcycles require stricter control for the reduction of CO and NMVOC emissions, while effective reduction of NOx and PM10 emissions can be achieved by better control of heavy-duty vehicles, buses and coaches, and passenger cars. Explicit provincial-level Monte Carlo uncertainty analysis, which quantified for the first time the Chinese vehicular emission uncertainties associated with both COPERT-derived and domestically measured emission factors by vehicle technology, showed that CO, NMVOC, and NOx emissions for the period 2006-2009 were calculated with the least uncertainty, followed by PM10 and CO2, despite relatively larger uncertainties in N2O and CH4 emissions. The quantified low uncertainties of emissions revealed a necessity of applying vehicle technology- and vehicle age-specific dynamic emission factors for vehicular emission estimation, and these improved methodologies are applicable for routine update and forecast of China's on-road motor vehicle emissions. IMPLICATIONS: This paper tracks the temporal and spatial variation characteristics in recent vehicular emission inventories in China based on dynamic emission factors. The fact that CO and NMVOC emissions kept growing at reduced rates and the NOx, PM10, and GHG emissions continued rising rapidly reveals that it was insufficient to bring down the rapid growth of NOx, PM10, and CO2 emissions by merely tightening emission standards and improving fuel quality of motor vehicles. The results will assist decision makers to formulate effective control policies for China's vehicular emissions. The improved methodologies are applicable for routine update of China's vehicular emission inventories.

Long-term trends and characteristics of visibility in two megacities in southwest China: Chengdu and Chongqing.

Visibility is a good indicator of air quality because it reflects the combined influences of atmospheric pollutants and synoptic processes. Trends in visibility and relationships with various factors in Chengdu and Chongqing, two megacities in southwest China, were analyzed using daily data from National Climatic Data Center and the Air Pollution Index (API) of the Ministry of Environmental Protection of China. Average annual visibility during the period of 1973-2010 was 8.1 +/- 3.9 in Chengdu and 6.2 +/- 4.3 km in Chongqing. PM10 dominates the reported primary pollutants in both cities, although concentrations have decreased from a high of 127.9 and 150 microg m3 before 2005 to 100.4 and 93.5 microg m(-3) in Chengdu and Chongqing, respectively. Low average visibility and extremely high levels of PM10 were observed in winter, whereas relative humidity had irregular and weak seasonal variations. Visibility in both cities has deteriorated in comparison to the 1960s and 1970s, mostly due-to the elevation of optical depth caused by anthropogenic pollution. Correlations and principal component analysis (PCA) were undertaken to determine the key factors affecting visibility. Visibility was only moderately correlated with PM10. In Chengdu, visibility displayed weak correlations with various factors, whereas visibility in Chongqing was most strongly related to relative humidity due to the atmospheric particulates in the region containing more hygroscopic components. PCA results further confirmed that high relative humidity and low wind speed increased the occurrence of low visibility events under high PM10 concentrations. Temperature and pressure, as indicators of weather systems, also played important roles in affecting visibility. Mathematical models of visibility prediction indicated that wind speed had the largest coefficients among all meteorological factors, and reductions in PM10 concentration only led to minor improvements in visibility.

Multi-scale analysis of the impacts of meteorology and emissions on PM2.5 and O3 trends at various regions in China from 2013 to 2020 3. Mechanism assessment of O3 trends by a model.

A multiscale analysis of meteorological trends was carried out to investigate the impacts of the large-scale circulation types as well as the local-scale key weather elements on the complex air pollutants, i.e., PM2.5 and O3 in China. Following accompanying papers on synoptic circulation impact and key weather elements and emission contributions (Gong et al., 2022a; Gong et al., 2022b), an emission-driven Observation-based Box Model (e-OBM) was developed to study the impact mechanisms on O3 trend and quantitatively assess the effects of variation in the emissions control over 2013-2020 for Beijing, Chengdu, Guangzhou and Shanghai. Compared with the original OBM, the e-OBM not only improves the performance to simulate the hourly O3 peak concentration in daytime, but also reasonably reproduces the maximum daily 8-hour average (MDA8) O3 concentrations in the four cities. Based upon the sensitivity experiments, it is found that the meteorology is the dominant driver for the MDA8 O3 trend, contributing from about 32 % to 139 % to the variations. From the mechanistic point of view, the variations of meteorology lead to the enhancement of atmospheric oxidation capacity and the acceleration of O3 production. Further evaluation to the emission changes in four cities shows that the O3-precursors relationships of the four cities have been changed from the VOC-limited regime in 2013 to the transition regime or near-transition regime in 2020. Though the NOx/VOCs ratios have been obviously decreased, the emission reductions up to 2020 were still not enough to mitigate O3 pollution in these cities. It is emphasized in this study that the strengthened control measures with maintaining a certain ratio of NOx and VOCs should be implemented to further curb the increasing trend of O3 in urban areas.

VOC species controlling O3 formation in ambient air and their sources in Kaifeng, China.

The concentration of ozone has been in a rising crescendo in the last decade while the fine particles (PM2.5) is gradually decreasing but still at a high level in central China. Volatile organic compounds (VOCs) are the vital precursors of ozone and PM2.5. A total of 101 VOC species were measured in four seasons at five sites from 2019 to 2021 in Kaifeng. VOC sources and geographic origin of sources were identified by the positive matrix factorization (PMF) model and the hybrid single-particle Lagrangian integrated trajectory transport model. The source-specific OH loss rates (LOH) and ozone formation potential (OFP) were calculated to estimate the effects of each VOC source. The average mixing ratios of total VOCs (TVOC) were 43.15 parts per billion (ppb), of which the alkanes, alkenes, aromatics, halocarbons, and oxygenated VOCs respectively accounted for 49%, 12%, 11%, 14%, and 14%. Although the mixing ratios of alkenes were comparatively low, they played a dominant role in the LOH and OFP, especially ethene (0.55 s-1, 7%; 27.11 µg/m3, 10%) and 1,3-butadiene (0.74 s-1, 10%; 12.52 µg/m3, 5%). The vehicle-related source which emitted considerable alkenes ranked as the foremost contributing factor (21%). Biomass burning was probably influenced by other cities in the western and southern Henan and other provinces, Shandong and Hebei.

A novel sample preparation method based on polarity grouping for comprehensive determination of 315 pesticides and other contaminants in wolfberry by liquid chromatography-tandem mass spectrometry.

A novel sample preparation method based on polarity grouping was developed for the comprehensive determination of 315 undesirable low-weight organic pollutants ranging from polar to weakly polar in wolfberry. The method involves the swelling of the sample in ammonium acetate buffer, two-phase extraction, three-phase extraction, and dispersive solid phase extraction (D-SPE) with the assistance of low-temperature centrifugation and analysis by ultrahigh performance liquid chromatography coupled with electrospray ionization tandem mass (UHPLC-ESI-MS-MS) by using the multiple reaction monitoring mode. The recoveries of the analytes with wide range of polarity were satisfactory. The matrix-fortified standard calibration curves were compared for quantification. The results of linearity were satisfactory with linear regression coefficients (R) ranging from 0.9901 to 1.000. The limits of quantification ranged from 1 µg/kg to 10.0 µg/kg, indicating the compliance of products with legal tolerances. The average recoveries for spiked wolfberry were in the range of 69.3 %-145.2 % with RSD values of 0.2 %-28.6 %. The inter-day precision was in the range of 0.2 %-27.0 %. For over 90 % of the analytes, the recoveries were 70 %-120 % with RSD values below 20 %. The application of this method in routine monitoring programs would imply a drastic reduction of both effort and time.

Silicon and gadolinium co-doped hydroxyapatite/PLGA scaffolds with osteoinductive and MRI dual functions.

Introduction: An ideal bone repair scaffold should have dual functions of osteoinductive ability and in vivo imaging. In this study, the simultaneous substitution of silicon (Si) and gadolinium (Gd) in hydroxyapatite (HA) as potential multifunctional bone graft materials has been successfully developed. Methods: A series of HA nanoparticles (HA NPs) doped with different proportions of Si and Gd were prepared. The chemical structure and phase composition of the materials were analyzed using Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD). The microstructure, magnetic properties, surface potential, and cytotoxicity of the materials were also analyzed. The magnetic resonance imaging (MRI) effect of Gd&Si-HA/poly(lactic-co-glycolic acid) (Gd&Si-HA/PLGA) composite materials was evaluated. Osteogenic-related gene expression, alkaline phosphatase (ALP) level, and mineralization capacity of MC3T3-E1 cultured on Gd&Si-HA/PLGA composite materials were also detected. Results and Discussion: The 1.5Gd&Si-HA@PLGA group showed good ability to promote osteogenic differentiation of cells. The MRI effect of the 1.5Gd&Si-HA@PLGA scaffold was observable. This HA material containing Si and Gd co-doping has a broad application prospect in the field of bone tissue engineering owing to its ability to enhance osteoinductive property and improve MRI effect.

[Pollution Characteristics and Source Apportionment of Atmospheric Volatile Organic Compounds in Winter in Kaifeng City].

In order to explore the pollution characteristics and sources of atmospheric volatile organic compounds (VOCs) in winter in Kaifeng City, based on the atmospheric VOCs component data obtained from the online monitoring station of the Kaifeng Ecological and Environmental Bureau (Urban Area) from December 2021 to January 2022, the pollution characteristics of VOCs and secondary organic aerosol formation potential (SOAP) were discussed, and the sources of VOCs were analyzed by using the PMF model. The results showed that the average mass concentration of VOCs in winter in Kaifeng City was (104.71±48.56) µg·m-3, and alkanes (37.7%) had the highest proportion of mass concentrations, followed by that of halohydrocarbons (23.5%), aromatics (16.8%), OVOCs (12.6%), alkenes (6.9%), and alkynes (2.6%). The averaged total SOAP contributed by VOCs was 3.18 µg·m-3, of which aromatics contributed as much as 83.8%, followed by alkanes (11.5%). The largest anthropogenic source of VOCs in winter in Kaifeng City was solvent utilization (17.9%), followed by fuel combustion (15.9%), industrial halohydrocarbon emission (15.8%), motor vehicle emission (14.7%), organic chemical industry (14.5%), and LPG emission (13.3%); solvent utilization contributed 32.2% of the total SOAP, followed by motor vehicle emission (22.8%) and industrial halohydrocarbon emission (18.9%). It was found that reducing VOCs emissions from solvent utilization, motor vehicle emission, and industrial halohydrocarbon emission was important to control the formation of secondary organic aerosols in winter in Kaifeng City.