In order to study the pollution characteristics and source contribution of PM_2.5 in Nanjing, PM_2.5 and its chemical composition were measured on-line from March 2018 to February 2019 in Xianlin area of Nanjing. The PMF and the CMB models were used to analyze the source contribution of PM_2.5. The resulted show that the average mass concentration of PM_2.5 in Nanjing during the study period was 54.3μg/m³, and the average concentration in winter was 76.4μg/m³. The main chemical components of PM_2.5 were NO₃^-(21.3%~30.8%)、SO₄^2-(18.9%~23.5%)、NH₄⁺(14.3%~16.2%). In terms of annual average, the PMF model showed the source contribution as:secondary inorganic aerosol (54.9%), coal combustion (17.4%), secondary organic aerosol (7.4%), vehicle source (7.1%), industry source (4.9%), dust (4.8%), other sources (3.4%); the CMB model showed the source contribution as:nitrate (33.0%), sulfate (24.0%), coal (16.4%), vehicle source (8.4%), secondary organic aerosol (7.1%), dust (5.7%), other sources (2.9%), and industry source (2.4%). The sources of PM_2.5 in different seasons were slightly different. The proportion of secondary inorganic aerosol in summer and winter was greater than that in spring and autumn. The proportion of coal in spring and winter was the largest, and the proportion of secondary organic aerosol was the largest in autumn. Combined with the 2017 emission inventory of Nanjing, the contribution of secondary aerosol from PMF and CMB was reanalyzed, and it was found that the main contribution of PM_2.5 in Nanjing Xianlin area came from coal combustion (PMF:34.14%, CMB:33.82%), vehicle source (PMF:27.33%, CMB:29.33%) and industrial source (PMF:26.76%, CMB:24.77%). PM_2.5 in Xianlin area of Nanjing was more affected by sources from coal burning, transportation and industry. It could be seen that the results of PM_2.5 source apportionment from PMF and CMB models basing on-line measurement have good consistency.

This study systematically analyzed the Water-Soluble Organic matter (WSOM) in PM_2.5 collected during September 2017 to August 2018 in the northernzone in Shenzhen. The mass concentration, mass spectraand sources of WSOM were obtained. The average mass concentration of PM_2.5 was (32.3±18.4)μg/m³. WSOM was determined to be 77.6%±14.0% of the organic matter (OM), with anaverage mass concentration of (9.4±5.7)μg/m³. As shown in the mass spectrometry, the average O/C ratio of WSOM was 0.57±0.99, which was within thetypical range ofthe O/C valuesof SOA. Meanwhile, the abundant C₂H₄O₂⁺ proved that biomass burning organic aerosol (BBOA) contributed significantly to the WSOM. Furthermore, positive matrix factorization (PMF) model was applied to perform source apportionment of WSOM and three reasonable factors were identified, including BBOA, more oxidized oxygenated OA (MO-OOA) and less oxidized oxygenated OA (LO-OOA), accounting for 16.5%, 51.7% and 31.8%, respectively. Compared to spring and summer, BBOA and MO-OOAcontributed more in autumn and winter,which was more closely related to inland pollution transport based on backward trajectory analysis. Thelittle variation of LO-OOA in different air masses possibly impliedits local sources. ¹⁴C measurement was conducted to help separate fossil and non-fossil emissions of WSOM, and the fossil fuel-derived secondary organic matterwas found to dominate the WSOM mass (53.9%). Therefore, it's necessary to strengthen the control of fossil fuel sources in order to reduce WSOM pollution.

PM_2.5 samples were collected during autumnin Xingtai City from October 15th to November 14th, 2017, and the water- soluble ions Cl^-, NO₃^-, SO₄^2-, NH₄⁺, Ca²⁺, Na⁺, Mg²⁺ and K⁺ in the PM_2.5 were determinedby ion chromatography. The results showed during sample collection period r(PM_2.5) was (130.0±74.9)mg/m³. The average water-soluble ion concentration was (69.8±11.4)mg/m³, which accounted for 33.6% of r(PM_2.5). SO₄^2-, NO₃^- and NH₄⁺ were the main ions in PM_2.5, totally accounting for 89.7% of the water-soluble ions in autumn. With the air pollution getting serious, the concentration of water-soluble ions increased with the increase of ρ(PM_2.5), and the proportion of NO₃^-, NH₄⁺ and SO₄^2- increased gradually. Conversely the proportion of other ions decreased, and Ca²⁺ was especially obvious which indicated that ρ(PM_2.5) was mainly affected by secondary inorganic transformation. The average value of SOR and NOR during sample collection period were 0.36 and 0.25, respectively, and showed that the secondary transformation of SO₂ and NO₂ is seriously important and the secondary pollution was more serious. In addition, SOR and NOR are positively correlated with relative humidity and air temperature, and SOR is more sensitive to both. PM_2.5 in Xingtai City was slightly alkaline during autumn. NH₄⁺ were primarily in NH₄NO₃ and NH₄HSO₄ forms in PM_2.5. The N/S average value was 2.13, indicating that mobile source contributed more to PM_2.5 during autumn. PMF analysis revealed that secondary transformation, combustion and dust were the main potential sources of the ionic components of PM_2.5 during autumn in Xingtai City.

In order to study the pollution characteristics and sources of carbon components in PM_2.5 in Handan City, samples of PM_2.5 were collected from April to December 2017 and the mass concentrations of organic carbon (OC) and elemental carbon (EC) in PM_2.5 were analyzed by thermal optical reflection (TOR). The results showed that the average annual concentrations of PM_2.5 and total carbon aerosol (TCA) were (88.87±58.89)μg/m³ and (31.45±23.35)μg/m³ respectively. The exceeding standard rate of PM_2.5 concentration was 50%, and TCA accounted for (38.23%±14.61%) of PM_2.5 during the sampling period, indicating that the pollution of carbon components was serious in Handan. The average mass concentration of TCA was (68.06±23.77)μg/m³ in winter, which contributed (46.86%±10.07%) to PM_2.5, and the concentrations of OC (37.09±13.05)μg/m³ and EC (8.72±3.78)μg/m³ in winter were higher than other seasons, indicated the carbon aerosol was polluted seriously. The OC/EC ratio was higher than 2 in each season, which indicated that Handan was polluted by secondary organic carbon (SOC) all year round. OC, EC and SOC were significantly positively correlated with SO₂ and NO₂, and negatively correlated with O₃ especially the correlation between carbon components and NO₂ was the strongest, indicating that the carbon component was most likely affected by vehicle exhaust emissions. Principal component analysis of the eight carbon components showed that road dust, coal combustion and vehicle exhaust were the main contributors to OC and EC in PM_2.5 in Handan City.

Six models were built for timely and accurate estimation of PM_2.5 concentration and pollution levels, namely K Nearest Neighbor (KNN) model, BP Neural Network (BPNN) model, Support Vector Machine (SVM) regression model, Gaussian Process Regression (GPR) model, XGBoost model and Random forest(RF) model. Ganzhou City of Jiangxi Province was selected as the study area. The hourly ground-based meteorological data, PM_2.5 concentration data and Merra-2reanalysis data from 2017 to 2018 were used for modelling. The results show that PM_2.5 concentration can also be predicted using visibility and meteorological data when pollutant observation data are missing. In terms of the prediction accuracy of PM_2.5 concentration, the XGBoost model performs best, followed by the RF model, and the GPR model is the worst. The prediction accuracy of the six models was generally highest in winter, followed by autumn and spring, and lowest in summer. Compared with other models, the XGBoost model exhibits a more accurate prediction performance for PM_2.5 pollution level prediction with the comprehensive accuracy rate of 87.6%. Moreover, XGBoost model has the advantages of short training and small memory consumption. Visibility (followed by the relative humidity and time variable) play a key factor in the XGBoost models for PM_2.5 concentration prediction. This study can provide a reference for environmental departments to accurately predict and forecast PM_2.5 concentration.

In order to capture the spatial-temporal variations and regional transport characteristics of air pollution in Changsha- Zhuzhou-Xiangtan urban agglomeration, the spatial-temporal variations of aerosol optical depth (AOD) were analyzed using the MODIS MAIAC data from 2008 to 2016. On this basis, the potential transport characteristics of air pollutant were studied using the Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model and global data assimilation system (GDAS) meteorological element data. Results showed that AOD showed a downward trend, with the most significant decline in spring and summer. The spatial distribution of AOD was mainly characterized by the high in west and north while low in east and south. In the meantime, it was closely related to economic development and urbanization. In addition, the long-distance transportation (>1500km), medium-distance transportation (500~1500km) and local transportation (0~500km) rates of air pollution were 16.56%, 30.7% and 52.74%, respectively. The potential diffusion of air pollutant mainly affected Hubei, Jiangxi, Anhui, Guangdong, Guangxi, Jiangsu and Zhejiang. This study not only helps to understand the spatial-temporal variations of air pollution in the Changsha-Zhuzhou- Xiangtan urban agglomeration, but also provides a scientific auxiliary basis for the regional joint prevention and control and the beautiful China construction.

Air samples were collected in the Dushanzi district of Xinjiang Uyghur Autonomous Region, China during the non-heating, heating and sandstorm periods for the analysis of volatile organic compounds (VOCs) by a preconcentrator coupled to a gas chromatography/mass spectrometer according tothe USEPATO-14 standard method. The results showed that group compositions of VOCs in Dushanzi district during the sampling period were ranked in the order ofalkanes (61.80%), alkenes (18.62%), aromatics (10.16%) and acetylene (9.42%). The secondary organic aerosol (SOA) formation potentials of VOCs as estimated by fractional aerosol coefficient (FAC) method revealed that aromatics contributed the most to SOA formation during non-heating, heating and sandstorm period, with contribution percentages of 97.8%, 87.28% and 69.52%, respectively. SPSS software and generalized additive model (GAM) were used to analyze the relationships among meteorological factors, VOCs, O₃ and NO_x. The results demonstrated that high temperature and dry weather were conducive to the formation of O₃. The O₃ formation in Dushanzi district seemed to be VOCs-limited, and alkenes such as 1-butene showed significant linear correlation with O₃.

VOCs emission characteristics of typical plywood industry in Shandong were determined using SUMMA canister-GC- MS/FID analysis system. The results showed that alkanes (13.81%~39.16%), oxygenated VOCs (5.68%~36.06%) and aromatics (3.58%~48.12%) were the main emission components of hot pressing and gluing processes, while exhaust gas discharges were dominated by oxygenated VOCs(6.49%~83.88%). The characterized VOC emissions compositions in each process were different; alkenes and alkynes(27.12%~39.38%) and aromatics(32.47%~45.63%) were the high OFP components of hot pressing and gluing process, and oxygenated VOCs(52.82%) in the exhaust gas discharge contributed the most to O₃ generation. Based on the SOAP evaluation, aromatics(97.08%~98.03%) were the main active components in all processes; also, the emission factor of VOCs in the Shandong plywood manufacturing industry was measured to be 0.89g VOCs/m³ plywood.

The burning for two kinds of cow dung from Qinghai and Tibet in domestic stove was simulated at a laboratory. The real-time emission concentrations of volatile organic compounds (VOCs) from their burning were obtained by a dilution sampling system and a proton-transfer-reaction time-of-flight mass spectrometry (PTR-TOF-MS). The consumed amounts of cow dung during combustion processes were recorded using an electronic balance. The real-time emission factors were calculated. Results showed that the combustion processes of 70g cow dung lasted for 1100~1500 seconds. The time series of VOCs concentrations from cow dung burning mostly showed a single peak distribution. Total VOCs concentrations for the cow dung burning from Tibet peaked at 450s with a concentration of 7.92×10^-6. The total VOCs concentrations for the cow dung burning from Qinghai peaked at 400s with a concentration of 6.01×10^-6. The real-time emission factors of VOCs emitted from cow dung burning ranged in 40.74~156.88mg/g. The variation trends of the emission factors for VOCs were different from those of VOCs concentrations, and they exhibited increasing trend along with the combustion process. The lowest emission factors of VOCs were found at 3~4 minutes after the cow dung burning. For the burning of cow dung from Tibet, methanol, formaldehyde and acetaldehyde accounted for the largest proportion of total VOCs emissions, as 24%±1.9%, 11.9%±1.8% and 27.4%±1.4%, respectively. For the burning of cow dung from Qinghai, the corresponding mass percentages were 22.0%±1.1%, 13.3%±2.9% and 17.7%±4.6%, respectively. This study firstly gives the real-time emission factors of VOCs from cow dung burning, which can provide basic data for the establishment of emission inventory with high time resolution and also helpful for researches on human health effects as the exposure to domestic fuels burning in Qinghai-Tibet Plateau region.

This paper focused on the variation ofthe organic waste gasemissions and the circumstance of pollution control from metal surface coating industry in Zhejiang Province in the year of 2014 and 2018. The kind of coating and thinners,and criteria pollutants used in the industrialwereanalyzed. The coefficient of generating and emission of volatile organic compounds (VOCs) from solvent-based coatings and water-based coatingswerecalculated. The results showed that the control of VOCs in 2018 was significantly more effective than that in 2014, the proportion of companyusing water-based coatings increased from 18% to 36%, and then the proportion of company using solvent-based coatings decreased from 82% to 64%. The pollutants of metal surface coating industry wererevealed to be xylene, butanol, ethyl acetate, butyl acetate, toluene, propylene glycol, ethylbenzene and styrene. At last, the VOCs generating coefficients of solvent-based coatings and water-based coatings were 0.72 and 0.31kg/kg, respectively. The VOCs emission coefficients of solvent-based coatings and water-based coatings in 2014 were 0.64 and 0.29kg/kg, respectively, and the values of which in 2018 were 0.48 and 0.21kg/kg, respectively.

Simulated thermal dismantling of WPCB (waste printed circuit boards) was carried out and VOCs (volatile organic compounds) discharged during this processwere analyzed. COSMO-RS (conductor-like screening model for real solvent) model was used to predict the solubility of VOCs with higher concentration by quantum chemistry simulation, study the influence of ILs (ionic liquids)' components andthe leading interaction energy during the absorbing process, and determine the suitable absorbents. The solubilityin different solvents were experimented to verify the potential utilization of COSMO-RS model. The results showed that:①ethyl acetate and cyclopentanonewere two main substances with higher concentration. The concentration was 43.1,153mg/m³ and 105, 252mg/m³, and the total concentration percentage was 76.3% and 67.3%under 240 and 250℃, respectively.②Higher σ-profile peak, longer cations and anions alkyl chain length and the existence of electrophilic group could increase the solubility of these two compounds. NTf₂-based ILs were chosen as excellent absorbents. Misfit and van de Waal energy played the leading roleduring the absorbing process. ③COSMO-RS model couldbe used to predict the solubility of ethyl acetate and cyclopentanone qualitatively and semi-quantitatively.

This paper introduces the design and characterization of a flow tube reactor (Jiao-FTR, termed as J-FTR) for the study of aerosol formation mechanism. The flow field, the injection effect of the movable inlet, as well as the average residence time of gases and particles in the J-FTR under different configurations and operating conditions were characterized using a combination of computational fluid dynamics (CFD) simulations and direct measurements. The results show that the way of flow addition in the premixing section, the main flow rate, and the movable inlet geometry significantly affect the flow field and the residence time of gases and particles in the J-FTR. The premixing section aids in the development of a laminar main flow in the reactor. When the main flow was smaller than 8L/min, the flow became laminar before it entered the main reaction section of the reactor. When the movable inlet employed a straight tube with a relatively larger inner diameter or a cross-tube, its injection effects can be largely reduced or avoided. These results not only provide important guidance for performing J-FTR experiments of VOCs oxidation and aerosol formation, but also provide reference for other researchers to design FTR and carry out flow tube experiment.

In order to reveal the spatio-temporal aggregation pattern of O₃, the observation data of O₃ concentration from 1144 monitoring stations in 338 cities of China was analyzed by using spatial interpolation and spatial self-correlation during 2016 to 2018. The results indicated an overall upward trend of O₃ concentration (90 percentile) in China (from 141.54µg/m³ in 2016 to 153.21µg/m³ in 2018). The O₃ concentration was the highest in densely populated areas such as North China, the middle and lower reaches of the Yangtze River. The spatial distribution of O₃ concentration showed a significant clustering pattern and similarity characteristic. And the clustering and similarity characteristic increased from 2016 to 2018. There was a differentiation from the north to the south of the annual cluster zones, which was presented in the form of the high-value cluster zones in the north while the low-value ones in the south. The high-value cluster zones were located in North China (22.19%~29.59%), while the low-value zones were located in South China (15.98%~22.19%). In addition, seasonally, the cluster pattern of high-value and low-value zones of O₃ concentration showed an evidently periodical clockwise variation. Over the three years, the spring cluster zones were identical to the annual ones. In summer, both high-value zones and low-value zones had gradually expanded towards the west. While in autumn, the cluster pattern differentiated from the east to the west changed by a clockwise-shift, after which the high-value zones (the low-value zones) move toward south (north) gradually by a clockwise-shift. In winter, the cluster zones differentiated from the north to the south, in the pattern of the high-value cluster zones in the south while the low-value ones in the north.

Simultaneous O₃ observation was carried out in both the eastern natural ecological zone and the western urban living area in Shenzhen from the autumn with high photochemical activity to the winter with low photochemical activity in 2018, and then the evolution process of O₃ was explored and discussed. The results showed that during October, the O₃ concentration observed in the eastern site was 128% higher than that in the western site near the ground. From the ground to an elevation of 450m, the O₃ concentration in the east decreased. Conversely, due to the titration effect occurring in the west, the concentration of O₃ increased in proportion to the elevation up to 450m. From 450m to 2km, the O₃ concentration decreased at both sites, with the O₃concentration in the western area being about 30% higher than that in the eastern area. The O₃ concentration above 2km was generally stable and can be regarded as the background concentration (~70µg/m³), providing a high regional background concentration for the autumn O₃ pollution in Shenzhen. Analysis of high pollution process showed that the O₃ pollution variation was consistent within the atmospheric boundary layer in Shenzhen, indicating that O₃ pollution was significantly affected by regional transport. The transport of O₃ at the high altitudes in the western area was more prominent. From autumn to winter, the O₃ concentration decreased continuously due to the weakened photochemical reactions, and the horizontal and vertical variation of O₃ concentration also decreased in Shenzhen. The O₃ pollution level was essentially controlled by the regional background inwinter in Shenzhen.

In this work, adsorption breakthrough curves of single component and binary n-pentane and cyclohexane on hypercrosslinked polymeric resin (H-resin) and macroporous polymeric resin (M-resin) were investigated, respectively. The results showed that adsorption of n-pentane and cyclohexane on two polymeric resins was mainly based on the dispersion force. Polymeric resins exhibited the higher adsorption capacity for cyclohexane, which had a higher molar polarization. For adsorption of binary n-pentane and cyclohexane on H-resin, the phenomenon of "roll-up" (C/C₀>1for n-pentane) was observed in the breakthrough curves since H-resin had stronger adsorption affinity to cyclohexane than to n-pentane. Moreover, the higher the concentration of cyclohexane was, the more significant the "roll-up" was. In addition, the competition phenomenon became insignificant with increasing the adsorption temperature from 30 to 50℃. However, co-adsorption was always observed for binary adsorption of n-pentane and cyclohexane on M-resin because M-resin, whose pore was mainly distributed in the region of macropore and mesopore, had similar adsorption affinity to cyclohexane and n-pentane.

Based on monitoring data of ozone (O₃) from 2015 to 2018 in Harbin and other typical cities, this study analyzed the temporal and spatial distribution characteristics of O₃ in Harbin, and its relationship with meteorological factors. The O₃ pollution in Harbin was less than that in Beijing, Shanghai, Guangzhou, Changchun, Shenyang and Dalian from 2015 to 2018. O₃ pollution in Harbin had obvious seasonal patterns, that the O₃ over-standard rate in spring and summer was higher than the rate in autumn and winter. The monthly variation showed an inverted "U" type, with the O₃ high values concentrated in May, June and July. The daily variation of O₃ concentration showed a single peak distribution, that high concentration occurred from 13:00 to 15:00. A "weekend effect" was observed, that the O₃ concentration on working days was slightly higher than that during weekends. Spatial distribution characteristics showed that the O₃ concentration in the peripheral areas and counties of Harbin was generally higher than that in the inner city center. From May to July when O₃ pollution occurred frequently, the solar radiation intensity was 800~1200W/m², and the O₃ excessive rate is tightly associated with high air temperature, high wind speed and low relative humidity.

Based on the synoptic pattern, ground observation data and WRF-CMAQ model, this study analyzed the characteristics of a sustained O₃ episode in Chengdu and surrounding areas from July 8-15, 2017. And the physical and chemical processes of this episode was quantified. Sensitivity experiments were used to calculate the relative contribution of regional transport and local photochemical reactions on this episode. The results showed that the sustained O₃ episode was mainly caused by the prevailing easterly wind in the Sichuan Basin, which leaded to the O₃ and its precursors in the eastern urban agglomerations being transported to Chengdu and surrounding areas. Unfavorable meteorological conditions, such as high temperature and low wind speed, were favorable for the formation of this O₃ episode. The process analysis indicated that the contribution of the gas phase chemical reaction was a positive source of O₃ in the daytime, and the contribution of the transport process was explosively increased during severe O₃ episode, which leaded to a rapid increase (up to 50μg/(m³·h)) in the net O₃near the ground. In addition, the sensitivity experiments showed that this episode was dominated by regional transport rather than the local photochemical reaction. Before the outbreak of O₃ concentration, high concentrations of O₃ and its precursors were transported along the wind field and accumulated in Chengdu and surrounding areas, resulting in enhanced O₃ formation during daytime.

We analyzed the spatial distribution and temporal variation trend of tropospheric NO₂ over Guangdong-Hong Kong-Macao Greater Bay Area (GBA) using the satellite retrieved data from the Ozone Monitoring Instrument (OMI) sensor, and the influencing factors for these temporal-spatial characteristics. The results showed that the tropospheric NO₂ decreased by about 2.8% per year from 2005 to 2018 over GBA. The wavelet coefficients showed that there was a 9 months of main oscillation period and the higher and lower concentration appeared in winter and summer, respectively. Due to the effects of anthropogenic emissions and various natural factors, the monthly variation of the tropospheric NO₂ was significantly different in time and space over GBA. The minimum and maximum values appeared in June and December, respectively, and the multi-years mean values were 3.9665×10¹⁵ and 12.3423×10¹⁵ molec/cm². The tropospheric NO₂ showed obvious spatial heterogeneity characteristics, the most obvious heterogeneity was in December. The high-value areas with serious NO₂ pollution over GBA were mainly found in the central region, such as Guangzhou, Foshan and Zhongshan cities. The maximum tropospheric NO₂ column density was up to 18.8306×10¹⁵molec/cm². It was about three times that of the surrounding areas, and the high-pollution gradually extended around areas. The low-value areas were mainly in northern Zhaoqing City and eastern Huizhou City, and the average tropospheric NO₂ concentration was about 7.1400×10¹⁵molec/cm². The growth rates showed a significant difference over GBA. The tropospheric NO₂ column density varies from -15×10¹⁵ to 6×10¹⁵molec/cm², and the growth rates from -65% to 65%. The increased areas occurred in northern Zhaoqing City and the eastern Huizhou city. The larger reduced were concentrated in the high value areas in the middle, and the largest reduced were the junction of Guangzhou City, Foshan City and Zhongshan City.

Based on the data from the vehicle inspection station, the "VKT-age" curve was introduced to obtain refined VKTs that could be classified according to vehicle type, fuel type, and vehicular emission standards. Three kinds of VKT were applied to develop emission inventories to evaluate how results were affected by the localization and refinement of VKT, including the recommended VKT from the official guide, the VKT only classified by vehicle type, and the VKT simulated by "VKT-age" curve. It was found that the localization and refinement of VKT could significantly reduce the uncertainties caused by VKT and improve the accuracy of emission inventories. The refined VKTs were applied to estimate the vehicle emissions in Qingdao in 2017. The emissions of CO, VOCs, NOx, PM10, NH3, and SO2 are 70.7, 11.4, 28.4, 1.0, 0.8, and 0.8 Gg, respectively. The analysis of the emission composition showed that scrapping older vehicles was still an effective policy for controlling vehicle emissions. By combining with the road network and traffic data, a gridded vehicle emission inventory with a high temporal-spatial resolution of 0.01°×0.01° was developed. The results showed that the emissions distribution varied significantly at different times. Taking NOx as an example, the morning and evening peaks of emissions occurred at 8:00 and 17:00, with the contribution of 8.17% and 7.53% to the daily emissions. The spatial heterogeneity was observed in emissions that decreased gradually from downtown to suburb and showed a line distribution along the freeway.

This paper applied the inventory method to estimate the non-carbon dioxide (non-CO₂) greenhouse gases (GHGs) emissions from agricultural sources from 1980 to 2016 in the Yangtze River Economic Belt, and developed three emission scenarios (high, medium and low) at provincial level for 2030 and 2050 based on assumptions of economic development and the decoupling between agriculture and environment. Results show that the non-CO₂GHGs emissions from agricultural sources in Yangtze River Economic Belt increased from 0.26 Gt CO₂-eq in 1980 to 0.32 Gt CO₂-eq in 2016. The trend will continue under the high scenario and medium scenario, as agricultural non-CO₂GHGs emissions will not peak by 2050. The area-specific emission intensity (agricultural GHG emission per agricultural land area) in Jiangsu, Hunan, Chongqing, Yunnan, Hubei and Anhui will increase under the medium scenario and medium scenarios, while that in Sichuan province remains a lower level under the three scenarios.

A fluidized bed reactor was designed to enhance the removal efficiency of ammonium (NH₄⁺-N) by immobilized microalgae. Influences of different operating conditions of this system on NH₄⁺-N removal efficiency were investigated systematically, including microalgae species, sewage up-flow velocity, photo period and light intensity. Results indicated that a highest NH₄⁺-N removal (96.7%) efficiency was achieved by employing immobilized Scenedesmus obliquus at 6.8m/h influence velocity, 8:16h L/D photoperiod and 4800Lux light intensity. Based on these optimum operation conditions, ammonium removal potential of microalgae was studied at 200mg/L COD. Results showed that NH₄⁺-N removal rate is higher than 95% when the initial NH₄⁺-N concentration is no higher than 50mg/L. A semi-continuous methodology for microalgae fluidized bed reactor was established, which significantly reduced the dependence of microalgae on organic carbon source in the process of biological assimilation. The study provides a theoretical guidance for the design of microalgae fluidized bed technology, which could be used to improve the NH₄⁺-N removal potential from low carbon wastewater.

In order to analyze the effect of salinity on NOB (nitrite-oxidizing bacteria) activity and kinetic characterization, NOB was enriched in a lab-scale SBR system with high concentration of nitrite wastewater in this study. The FISH (fluorescence in situ hybridization) analysis showed that Nitrobacter accounted for(81%±6%)of total bacteria. The maximum specific nitrite oxidation rate was (42.5±0.9)mgN/(gVSS·h). The effect of salinity on NOB activity was investigated using this mixed culture. The kinetic parameters of NOB (Ko, K_S) were both measured under salinity of 10g/L. Results showed that compared with salinity 0g/L, the activity of NOB decreased 3.3% unders alinity of 15g/L and decreased 11% under salinity of 10, 20g/L. When salinity was 10g/L, the maximum specific nitrite oxidation rate was (37.9±0.7)mgN/(gVSS·h). The half-saturation constant for oxygen (Ko) and nitrite (K_S) were (1.51±0.06), (6.06±0.15) mg/L. The values of Ko and K_S were higher than recommended value of ammonia-oxidizing bacteria (AOB) in ASM2model. It is suggested that salinity could reduce maximum specific nitrite oxidation rate and affect the oxygen affinity and substrate (nitrite) affinity of NOB.

Based on 16S rRNA genes-Illumina MiSeq high-throughput sequencing, this study is to investigate the community and structure of characteristic microbial communities related to nitrification under four C/N ratios (0、5、10、15) settled in four parallel laboratory-scale sequencing batch reactors (SBRs, denoted as R₀、R₅、R₁₀、R₁₅) to better understand the biological mechanisms of how does C/N ratio influence the nitrification. Results indicated that effective removal of ammonia nitrogen (removal efficiency > 95%) and COD (removal efficiency > 90%) were achieved in four C/Ns, and TN has also been reduced to varying degrees. In addition, C/N ratio has an important impact on the diversity, community and function of the bacterial communities. The largest α-diversity values of Chao1 (922), ACE (1232.4), Shannon (6.76) and Simpson (0.96) were achieved in R₀, which represents with highest richness and diversity of bacterial community, while the lowest was achieved in R₅. 9 phyla such as Proteobacteria, Bacteroidetes, Cyanobacteria and so on were found to be major groups with higher relative abundance at the phylum. The most dominant bacterial is affiliated with Proteobacteria comprised 40.7%~65.2% in the four sludge samples. The relative abundance of key microorganisms as Nitrosomonadaceae and Nitrospira related to nitrification decreased sharply with increasing C/N. A total of 34 groups of microorganisms with significant differences were obtained based on LEfSe analysis, thereby key biomarkers of the microflora were obtained at the microbiological classification level under each C/N condition.

The activity recovery effect of CANON-MBBR reactor which had experienced short-term storage at low temperature (20days, 15℃) and low load operation at room temperature (25℃) was studied by using different recovery methods. The results showed that the recovery rate of TN removal load reached 102% by recovering the temperature first and then slowly increasing the influent load. If the influent load was directly raised to the original level without the increase of temperature, the detachment of biofilms of the suspended carriers could happen due to the decrement of EPS content, therefore the recovery rate of TN removal load was lowered to 84%. In addition, the recovery rate of TN removal load reached 96% after 25days of SBR operation under low load and normal temperature (25℃) by the same recovery method. The dominant functional microorganisms in CANON-MBBR system were identified as Nitrosomonas and Candidatus Kuenenia. The relative abundance of both genus could reach over 11% and 27% respectively after the system entered the stable operation by appropriate recovery methods. The microbial composition of biofilms was not significantly influenced by the biofilm detachment.

Biomineralization mediated by A.ferrooxidans to promotes the transformation of soluble Fe into secondary iron minerals is of great significance to the treatment of acid mine drainage (AMD). As a chemoautotrophic bacteria, A.ferrooxidans are vulnerable to hydraulic shock and loss. To ensure a higher Fe²⁺ oxidation and mineralization rate, immobilization method is often used to increase the bacterial density. In the study, schwertmannite, K-jarosite and NH₄-jarosite immobilized with A.ferrooxidans were synthesized under the same initial conditions (pH=2.30, Fe²⁺ concentration 4.48g/L, and A.ferrooxidans density 8×10⁶cells/mL). The he Fe²⁺ oxidation properties of A.ferrooxidans before (fixed state) and after (free state) minerals dissolution and the A.ferrooxidans fixing ability on minerals were compared. Results indicated that the dry weight of biosynthesis minerals was schwertmannite (0.24g) < NH₄-jarosite (0.35g) < K-jarosite (0.67g), however, A.ferrooxidans fixing ability was in the order of schwertmannite > NH₄-jarosite > K-jarosite. According to the Fe²⁺ oxidation rate of free A.ferrooxidans, calculated the effective biomass of A.ferrooxidans immobilized by schwertmannite, NH₄-jarosite and K-jarosite was 5.33×10⁷~5.33×10⁸, 5.72×10⁶~5.72×10⁷, and 6.35×10⁶cells/g (dry basis), respectively. The effective biomass of secondary iron minerals not only directly affects the oxidation rate of Fe²⁺, but also indirectly determines the mineralization removal effect of total Fe in AMD system.

In order to achieve the rapid, economical and efficient denitrification of actual low C/N wastewater, sodium thiosulfate and pyrite was used to treat the biochemical tail water for antibiotic production. The denitrification performance, the feasibility and stability of this practical wastewater treatment system were explored, and the microbial community was revealed by high-throughput sequencing. In this paper, three identical denitrification filter column reactors were used to fill 200, 400 and 400mL of pyrite with sodium thiosulfate dosage of 1、0.75、0.5times of the theoretical amount. The results showed that the removal rate of NO₃^--N in the first two reactors remained above 72%, while the denitrification performance of the third reactor was poor. The effluent pH value of the three reactors was basically between 6.8 and 8.0, which was suitable for the survival of sulfur autotrophic microorganisms without additional alkalinity. Compared with sulfur, sodium thiosulfate not only can be replenished at any time and avoid waste, but also can improve mass transfer between microorganism and electron donors, and slow down the blocking phenomenon of the system; The functional bacteria in the three reactors were Sulfurimonas and Thiobacillus, accounting for 27.32%, 25.37% and 18.4% respectively.

A series of amphoteric-cationic complex modified bentonites were prepared with amphoteric modifier dodecyldimethyl betaine(BS) and gemini cationic surfactant ethylene ditetradecyl dimethyl ammonium chloride(EB), Cr(VI) adsorption on BS+EB complex modified bentonite under different modification ratio, temperature, pH and ionic strength and its thermodynamic characteristics were studied by batch method, its adsorption mechanism was discussed by comparing surface charge and infrared spectrum of BS+EB complex modified bentonite before and after Cr(VI) adsorption. The results showed that EB complex modification significantly enhanced its adsorption capacity for Cr(VI), which was 2.02~27.25 times higher than that on BS amphoteric modified bentonite. The Cr(VI) adsorption increased with an increase of EB modification ratio at 30℃ and was ordered by BS+150EB(BS and 150% EB complex modified bentonite) > BS+100EB > BS+50EB > BS+25EB > BS > CK(bentonite). The Cr(VI) adsorption on both CK and BS modified bentonite was a spontaneous process with a characteristics of both enthalpy-increase and entropy-increase, except it on BS+EB complex modified bentonite decreased with an increase of temperature, showing a characteristics of negative temperature effect. With an increase of pH and ionic strength, the adsorption of Cr(VI) on each sample decreased gradually. The results of infrared spectra and soil surface charge confirmed that charge attraction was the main mechanism for Cr(VI) adsorption on BS+EB complex modified bentonite.

In this study, phosphoric acid was used as an activator to modify chaff-derived biochar for the obtainment of functional chaff-derived biochar(fCBC), which was rich in active functional groups. Then fCBC was utilized as a carrier material for manganese sulfide (MnS-fCBC), which could be applied to effectively remove cadmium(Cd) in aqueous solution. The effects of initial Cd concentration, initial pH value and dosage of MnS-fCBC on the adsorption capability were systematically evaluated. The MnS-fCBC showed an excellent adsorption performance of Cd. Under the condition of the intial Cd concentration was 200mg/L, solution pH value was 6, adsorbents dosage was 1g/L, the maximum adsorption capacity of MnS-fCBC came to 145.15mg/L. The adsorption reaction was significantly affected by the pH value, and a better removal performance could be obtained under weakly acidic conditions. To characterize the structure of MnS-fCBC, X-ray diffractometer (XRD) and Raman spectroscopy (Raman) was applied, and the removal mechanism of Cd was discussed by batch experiments and characterization results, showing that surface complexation and chemical precipitation were the main mechanisms of Cd removal. Recycle tests showed that the material still had significant Cd removal capability for five successive 24h adsorption-desorption cycles, which showed that MnS-fCBC had high reusability. Therefore, MnS-fCBC could be used as an effective Cd adsorbent for the treatment of Cd-containing wastewater.

To explore the emission characteristics of steroid estrogens in biogas slurry, the anaerobic and aerobic tank effluent samples were continuously monitored in summer, autumn, and winter by solid phase extraction-high performance liquid chromatography-tandem mass spectrometry (SPE-HPLC-MS/MS) analysis method from a typical dairy farm in Chongqing city, China. The results showed that the total amounts of five steroid estrogens (estrone; 17α-estradiol; 17β-estradiol; estriol; estrone-3-sulfate) were ranged at 347.28~2117.65ng/L and 10.75~1070.00ng/L in anaerobic and aerobic tank effluent, respectively. The anaerobic tank effluent was dominated by E1, 17α-E2, and 17β-E2, and the aerobic tank effluent was dominated by E1 and 17β-E2.The average removal efficiency of E1, 17β-E2, and 17α-E2by aerobic treatment reached 85.70%, 56.82%, and 57.32%, respectively. Moreover, E1-3S was effectively removed under anaerobic treatment. Under the effect of microorganisms, the interconversion amongE1, 17α-E2, and 17β-E2 was found both in anaerobic and aerobic treatment. However, the low detection frequency of E3 indicated that the ratio of estrogen to E3 was lower in the system. The assessment of simulated estrogen activity (EEQ_95th) was reduced by an average of 70.34% after anaerobic-aerobic treatment, but the estrogens ecological risk of biogas slurry could not be ignored and required continuous monitoring.

The effects of light intensity, initial concentration, free chlorine, bromine ion and pH value on the photodegradation of dibromonitromethane (DBNM) were studied by single variable control method, and the photodegradation kinetics of DBNM was discussed. The results showed that the photodegradation of DBNM under UV treatment followed first-order kinetics. The photodegradation rate of DBNM decreased with the increasing of initial concentration, increased with the increasing of light intensity and pH value. The presence of bromine ions would slightly promote the photodegradation of DBNM. The addition of free chlorine could significantly accelerate the photodegradation rate of DBNM, and could transform DBNM into the other halonitromethanes (HNMs) which were mainly composed of bromochloronitromethane (BCNM) during the degradation process. The results of this study could provide a reference for controlling the formation of DBNM during water treatment and reducing the risk of water quality safety.