A novel exopolysaccharide from deep-sea bacterium Zunongwangia profunda SM-A87: low-cost fermentation, moisture retention, and antioxidant activities.

Many marine microorganisms can secrete exopolysaccharides (EPSs) which have important applications in biotechnology. We have purified a novel EPS from deep-sea bacterium Zunongwangia profunda SM-A87, identified its glycosyl composition and linkage, and optimized its production to 8.9 g/l in previous studies. To reduce the fermentation cost, an economical fermentation medium containing 60.9 % whey, 10 g/l soybean meal, and 2.9 % NaCl was developed. The EPS yield of batch fermentation in this medium reached 12.1 ± 0.3 g/l. Fed-batch fermentation was conducted and led to an EPS yield of 17.2 ± 0.4 g/l, which represents the highest EPS yield ever reported for a marine bacterium. The EPS was extracted and it displayed good rheological properties, moisture-retention ability, and antioxidant activity. Particularly, its moisture-retention ability is superior to that of other marine bacterial EPSs reported to date. SM-A87 EPS also showed high antioxidant activity. These results suggest that SM-A87 EPS has promising potentials in biotechnology.

[Spatial and Temporal Distribution Characteristics of Ozone Concentration and Population Health Benefit Assessment in the Yangtze River Delta Region from 2017 to 2020].

In recent years, the ozone (O3) concentration has showed a rising trend in China, becoming second only to PM2.5 as an important factor affecting air quality. To grasp the spatial-temporal variations characteristics of O3 and the associated health impacts during the implementation of the three-year plan on defending the blue sky in the Yangtze River Delta (YRD) region, data collected from 210 monitoring stations in the YRD from 2017 to 2020 were analyzed using the global Moran's index and Getis-Ord Gi* index methods, and the associated health benefits of reduced O3 exposure were evaluated using the health risk and environmental value assessment methods. The results showed that during the study period, the interquartile range (IQR) of the annual average O3 concentration and that of the warm season both presented a declining trend. The average O3 concentrations in both warm and cold seasons showed a similar spatial distribution pattern, with the northern part exhibiting the higher concentrations and the southern part showing the lower concentrations. Furthermore, the O3 concentrations in the warm season were characterized by high O3 concentrations clustering in the northern and central part of the region. The proportion of the population exposure to annual average O3 concentration over 160 µg·m-3 decreased from 72.3% in 2017 to 34.8% in 2020 in the YRD. Although the population-weighted annual mean O3 concentration in the whole YRD region showed a downward trend, some cities in western Anhui province, northern Jiangsu province, and central Jiangsu province showed fluctuations and even an increasing trend. In terms of health benefits, there were 3782 cases (95% CI:2050-5511 cases) of avoided premature deaths associated with reduced O3 concentrations in the warm season in 2020 compared to 2017. The total health benefit was 26198 million yuan (95% CI:14201-38175 million yuan). Compared to the cost of the main O3 precursor emission reduction, the cost-benefits ratio was 1:1.67 to 3.23.

[Chemical Composition and Characterization of Nitroaromatic Compounds in Urban Areas of Shanghai].

The compositional characteristics, concentration of nitroaromatic compounds(NACs) in PM2.5 in urban Shanghai, and their correlation with gaseous precursors were investigated. A total of 39 winter and 46 summer PM2.5 samples from 2020 to 2021 were collected using a high-flow sampler and analyzed via ultra-performance liquid chromatography coupled with ESI-Orbitrap high-resolution mass spectrometry(UPLC-Orbitrap-HRMS). Quantitative analysis was performed on 12 NACs compounds, combined with backward trajectory meteorological elements, molecular composition, and classification analysis of CHON substances. The results showed that a total of 12 NACs had an average concentration in winter of 17.1 ng·m-3, which was three times higher than that in summer(5.7 ng·m-3), mainly due to air masses in winter coming primarily from the northern part of China with more biomass burning, whereas more air masses in summer came from the cleaner southeastern ocean. 4-Nitrophenol was the most abundant species of NACs in winter, whereas 4-nitrophenol(clean days) and 4-hydroxy-3-nitrobenzoic acid(polluted days) were the most abundant species in summer. Qualitative analysis based on features such as aromatic ring equivalence number(Xc), O/C, and H/C values for the identification and characterization of monocyclic and polycyclic aromatic compounds showed that CHON compounds were mainly aromatic compounds in winter and summer in urban Shanghai. The number and abundance of CHON compounds detected on PM2.5 polluted days were 2 and 1.5 times higher(winter) and 2.5 and 2 times higher(summer) than that on clean days, respectively. Comparing the analysis results of clean and polluted days in winter and summer, it was found that 80% of the CHON compounds with a relative abundance in the top 10 had O/N ≥ 3 and RDBE values between 5 and 8. The results suggest that these highly abundant CHON analogs may have had mononitro- or dinitro-substituted benzene rings. Correlation analysis between gaseous precursors and NACs indicated that oxidative reactive formation of VOCs(benzene, toluene, etc.) from anthropogenic emissions was the main source of NACs in summer. By contrast, it was influenced by a combination of biomass combustion emissions and secondary formation of oxidative NOx from anthropogenic VOCs in winter.

[Characteristics and Cause of PM2.5 During Haze Pollution in Winter 2022 in Zhoukou, China].

The characteristics and main factors of causes of haze in Zhoukou in January 2022 were analyzed. Six air pollutants, water-soluble ions, elements, OC, EC, and other parameters in fine particulate matter were monitored and analyzed using a set of online high-time-resolution instruments in an urban area. The results showed that the secondary inorganic aerosols(SNA), carbonaceous aerosols(CA, including organic carbon OC and inorganic carbon EC), and reconstructed crustal materials(CM, such as Al2O3, SiO2, CaO, and Fe2O3, etc.) were the three main components, accounting for 61.3%, 24.3%, and 9.72% in PM2.5, respectively. The concentrations of SNA, CA, CM, and SOA were increased, accompanied with higher AQI. The sulfur oxidation rate(SOR) and nitrogen oxidation rate(NOR) in January were 0.53 and 0.46, respectively. The growth rates[µg·(m3·h)] of sulfate and nitrate were 0.027(-5.89-9.47, range) and 0.051(-23.1-12.4), respectively. During the haze period, the growth rates of sulfate and nitrate were 0.13 µg·(m3·h)-1and 0.24 µg·(m3·h)-1, which were 4.8 and 4.7 times higher than the average value of January, respectively. Although the sulfur oxidation rate was greater than the nitrogen oxidation rate, the growth rate of nitrate was approximately 1.8 times that of sulfate owing to the difference in the concentration of gaseous precursors and the influence of relative humidity. The growth rates of nitrate in SNA were significantly higher than those of sulfate on heavily polluted days. The values of SOR, NOR, and concentrations of SNA and SOA during higher AQI and humidity periods were higher than those in lower AQI and humidity periods. The Ox(NO2+O3) decreased with the increase in relative humidity. The SOA was higher at nighttime, increasing faster with the humidity than that in daytime. Under the situation of lower temperature, higher humidity, and lower wind speed, the emission of gaseous precursors of SNA requires further attention in Zhoukou in winter. Advanced control strategies of emissions of SO2 and NO2, such as mobile sources and coal-burning sources, could reduce the peak of haze in winter efficiently.

Characterization of bacterial polysaccharide capsules and detection in the presence of deliquescent water by atomic force microscopy.

We detected polysaccharide capsules from Zunongwangia profunda SM-A87 with atomic force microscopy (AFM). The molecular organization of the capsules at the single-polysaccharide-chain level was reported. Furthermore, we found that with ScanAsyst mode the polysaccharide capsules could be detected even in the presence of deliquescent water covering the capsule.

[Characteristics of Nitroaromatic Compounds in PM2.5 in Urban Area of Shanghai].

Nitroaromatic compounds (NACs) are an important class of nitrogen-containing compounds in fine particles. The investigation of characteristics and seasonal variation of NACs in PM2.5 increases our knowledge about nitrogen-containing compounds and contributes to the scientific basis in formulating reduction policies of NOx in urban areas. In this study, we analyzed the chemical composition of PM2.5 samples collected from March 2018 to February 2019 in an urban location in Shanghai. A total of 2439-3695 organic molecular formulas were detected using UPLC-Orbitrap MS. Nine NACs were quantified using an internal standard method. In spring, ρ(NACs) ranged from 3.12 to 16.76 ng·m-3, and the average concentration was 9.31 ng·m-3. In summer, it ranged from 1.05 to 9.70 ng·m-3, and the average value was 4.16 ng·m-3. In autumn, it ranged from 2.87 to 36.27 ng·m-3, and its average was 9.84 ng·m-3. In winter, it ranged from 4.83 to 56.23 ng·m-3, and the average was 22.37 ng·m-3. 4-Nitrophenol accounted for more than 25% of the quantified NACs in different seasons. In summer, the concentration of 5-nitrosalicylic acid accounted for 36%, but it decreased to 19% in winter. NACs in summer mainly originated from secondary formation, as evidenced by their clear correlation with the oxidant level, whereas biomass burning became the main source of NACs in winter.

[Time-Determination and Contribution Analysis of Transport, Retention, and Offshore Backflow to Long-Term Sand-Dust Coupling].

Continuous on-line observation of particulate matter and PM2.5 chemical composition was conducted from October 15th to November 7th 2019 in East China. During the observation period, a wide range of dust-related processes took place. According to supplementary urban air quality assessment affected by dust (hereafter referred to as supplementary provisions), the observations were divided into four stages including pre-dust event, dust Ⅰ, dust Ⅱ, and post-dust event. The dust Ⅰ stage represented the processes of transportation and retention, while the dust Ⅱ stage represented processes of backflow from the sea and scavenging. The start time of the studied dust event was October 29th 08:00-09:00 based on the supplementary provisions, dust tracers, and air quality models; however, disagreements existed between these data sources with respect to the finishing time. The supplementary provisions could not effectively distinguish backflow dust from sea, and results from different dust tracers were variable. The WRF-CMAQ model simulated dust variation trends well but overestimated short-term suspended dust and backflow dust. PM10, PM2.5, and trace element concentrations were much higher during dust events than during non-dust periods, with highest daily concentrations of (234.8±125.5), (76.8±22.5), and (17.54±10.5) µg·m-3, respectively, which occurred on October 29th. During the dust event, concentration of crustal elements were remarkably high in PM2.5. At the same time, secondary ions (SO42-, NO3-, and NH4+) contributed less to PM2.5 mass concentrations. Four major crustal elements (Al, Si, Ca, and Fe) accounted for 23.5% and 13.7% of the mass concentration of PM2.5 and secondary ions accounted for 24.3% and 41.9% during dust Ⅰ and dust Ⅱ stages, respectively. Based on PMF source apportionment, Ca abundance, PM2.5/PM10 in dust sources, and the reconstruction of crustal material, dust particulates accounted for 43.4%-50.0% of PM2.5 and backflow dust accounted for 19.2%-24.7% of PM2.5.

[Audit Indicators and Suggested Ranges for Data Validation of Chemical Components in Ambient PM2.5: A Case Study of the Yangtze River Delta].

Diagnostic indicators for the validation of PM2.5 compositional data were calculated, based on the monitoring results of approximately 2100 ambient samples collected in the Yangzi River Delta from 2014 to 2017. According to the results of a correlation analysis, we propose that the audit indexes of the monitoring data of PM2.5 components in ambient air should include:equivalent ratios of anion-cation charge balance(A/C), the consistency between sum of all measured components(∑species) and weighed PM2.5, the consistency between mass reconstructed PM2.5(PM2.5, reconstructed) and weighed PM2.5, the chemical consistency between elemental S and water-soluble SO42-, elemental K and water-soluble K+, and the chemical consistency of theoretical and tested NH4+. The double-sided 95% reference ranges of anion-cation equivalent balance (A/C), ∑species/PM2.5, PM2.5, reconstructed/PM2.5, S/SO42-, and K/K+ ratios were determined in terms of P2.5 and P97.5 as follows:(0.82, 1.35), (0.63, 0.94), (0.62, 1.00), (0.28, 0.50), and (0.66, 2.31). These diagnostic indicators were helpful for judging the errors of chemical component analysis and retain seasonal variation stability. In most cases, NH4+ existed in the form of NH4NO3 and (NH4)2SO4 in spring and summer. With the approach of autumn and winter, it transformed to NH4NO3, (NH4)2SO4, and NH4Cl. The results of literature verification showed the pass rate of A/C was 87.1% and the rate of other indexes was 100%, indicating that the above audit indexes we propose could be applied to not only the Yangzi River Delta but the entire country. Furthermore, there were certain conditions in applying the diagnostic indicators. The S/SO42- ratio worked well with PM2.5 ≥ 40 µg·m-3 in summer and with 60 µg·m-3 ≤ PM2.5 ≤ 140 µg·m-3 in spring, autumn, and winter. Other audit indexes were available universally in all weathers under the condition of PM2.5 ≥ 60 µg·m-3.

[Observation of Aerosol Optical Properties and New Particle Formation in the Yangtze River Delta].

In a recent field campaign focused on air quality study, aerosol optical properties, particle number concentration, and PM2.5 components were monitored in Changzhou, Jiangsu Province, from May 27 to June 27, 2019. An array of instruments were deployed that included scanning mobility particle size spectrometer (SMPS), aethalometer (AE33), cavity attenuation phase shift single albedo monitor (CAPS-ALB), monitor for aerosols and gases in ambient air (MARGA) and RT-4 organic carbon/elemental carbon (OC/EC) carbon analyzer to study the ① changes in chemical composition and optical parameters of the new particles generated during the campaign period. ② comparison of the aerosol extinction coefficient recorded by these instruments and measured value in the reconstruction of IMPROVE (interagency monitoring of protected visual environment) and the calculated coefficient using MIE theory model were carried out. During the entire campaign, two new particle generation events were observed and also found that the particle size continued to increase from 4 nm to 64 nm. It was monitored that in the initial stage of new particle generation, sulfate contributed greatly. The measured average aerosol extinction coefficient during the period of particle generation, using these instruments was 95.40 Mm-1, while the average aerosol extinction reconstruction using the IMPROVE model was observed to be 140.20 Mm-1. The theoretical calculations based on Mie theory model yielded an average extinction coefficient of 93.54 Mm-1. It was found that the average aerosol extinction in Changzhou is lower than the average value of the urban aerosol extinction coefficient, which is measured to be 300 Mm-1 in China, during this period. The deployment of multiple instruments in a single campaign is more desirable because the combination of all observations helped in better characterization of the physicochemical properties of ambient aerosols from various aspects, including particle size spectrum and chemical composition.

[Chemical Compositions, Mass Concentrations, and Emission Factors of Particulate Organic Matters Emitted from Catering].

Catering is an important emission source of atmospheric particulate organic matters (POMs). Mass concentrations, chemical compositions, and emission factors of POMs emitted from catering were studied based on simulation experiments. The effects of different cooking methods, various ingredients, oils, and other factors were investigated. The results showed that the species of POMs emitted from catering were largely influenced by cooking methods, ingredients, and oils. Among all the quantified POMs, the average mass fraction was 68.9%, 20.3%, and 4.2% for N-alkanes, sterols, and fatty acids (including saturated fatty acids and unsaturated fatty acids), respectively. The remaining 5.42% was constituted by dicarboxylic acids, polycyclic aromatic hydrocarbons, monosaccharide anhydrides, and hopane compounds. The average ingredient emission factor was 0.0131 g·kg-1, ranging from 0.0014 g·kg-1 to 0.0271 g·kg-1. The ingredient emission factors of the meat cooking process were much larger than those of the vegetable cooking process. The average oil emission factor was 1.8230 g·kg-1, ranging from 0.0019 g·kg-1 to 10.1730 g·kg-1. The oil emission factors of barbecuing were much larger than those of other cooking methods.

[Exposure Levels, Sources, and Health Risks of Heavy Metal Components of PM2.5 in Housewives in Rural Shanghai].

To investigate exposure characteristics and potential health risk of PM2.5-bound heavy metals in housewives in rural areas, 265 personal exposure samples from 143 subjects were collected in the Songjiang district, Shanghai from February 2017 to June 2018. Mass concentrations of 13 elements in PM2.5 were determined by energy-dispersive X-ray fluorescence spectrometry (ED-XRF). The sources of heavy metal components in PM2.5 were analyzed using positive matrix factorization (PMF). The inhalation health risks of exposure to Ni, V, Cr, Mn, As, and Pb were analyzed using the US EPA health risk assessment model. The results showed that the average concentration of personal exposure to PM2.5 was 40.61 µg·m-3 in housewives, which was higher than the concentration at peripheral monitoring stations. The carcinogenic risks of Cr(Ⅵ)and As exceeded the acceptable risk level (10-6). The non-carcinogenic risks of V, Cr(Ⅵ), Mn, Ni, and As were all below the safety threshold, while the total non-carcinogenic risks of these five elements were higher than the safety threshold (>1). The results of PMF indicated that resuspended dust and indoor dust(43.8%), the metallurgy industry(34.6%), coal combustion(14.5%), and fossil-fuel combustion(7.2%)were the major sources of ten elements (Al, Ti, V, Cr, Mn, Fe, Ni, Zn, As, and Pb) in PM2.5. Based on the results of health risk assessment of pollution sources, control measures on the metallurgy industry and fossil-fuel combustion should be further strengthened.

[Secondary Aerosol Formation in Urban Shanghai: Insights into the Roles of Photochemical Oxidation and Aqueous-Phase Reaction].

Secondary species are one of the most important components of PM1 particles. To investigate the contributions as well as the factors that affect the formation of the secondary aerosols, a high-resolution time-of-flight aerosol mass spectrometer (HR-TOF-AMS, AMS) was employed to characterize sub-micron particles (PM1) during spring and summer in urban Shanghai. Organics were dominant in PM1 particles and comprised around 55% of the total PM1 mass concentration, followed by sulfate (24%) and nitrate (10%). Positive matrix factorization was further applied to explore the sources of the organics. It was found that primary and secondary organic aerosols accounted for around 34% and 66% of the total organics, respectively. Three episodes were observed during the measurements, where secondary species increased substantially. Increases of secondary species were represented by increases of sulfate and LV-OOA1 in spring, especially during the noontime, thus indicating that their formation is promoted by photochemical oxidation; yet in summer, photochemical and aqueous chemistry together accelerate the formation of secondary species, as indicated by the good correlations between nitrate and aerosol liquid water as well as between SOA and Ox. Overall, we found that contributions from secondary organic and inorganic aerosols to total PM1 particles were 35.5% and 43%, respectively. This study highlights that the influence of photochemical and aqueous chemistry is significant in the promotion of secondary species formation in Shanghai.

[Chemical Composition Characteristics of PM2.5 Emitted by Medium and Small Capacity Coal-fired Boilers in the Yangtze River Delta Region].

Seven small and medium coal-fired boilers were selected to analyze the emission factors and chemical composition characteristics of PM2.5, and the efficiency of the dust collection unit in removing PM2.5, OC, and EC of different particle sizes. At the outlet of the dust collection unit, PM2.5 mass emission factor was around 0.047-0.283 g·kg-1 with an average of (0.146±0.081) g·kg-1. SO42- was the most abundant ionic component, followed by NH4+ and Ca2+. S was the most abundant among all the elements, followed by Al, Ca, and Fe. The contents of OC and EC fluctuated greatly, and the ratio of OC and EC produced by each boiler was greater than one. In the range of the measured particle sizes, the mass concentration of PM2.5 showed a singlet or bimodal distribution, and the peak value appeared at 0.07-0.12 µm and greater than 1 µm in bimodal distribution. The mass concentration of OC showed a bimodal or trimodal distribution, and the peak value appeared at 0.04 µm, 0.20-0.31 µm, and greater than 1 µm in trimodal distribution. The efficiencies of the dust collection unit in removing PM2.5, OC, and EC were 66%, 53%, and 23%, respectively.

[Analysis of Non-polar Organic Compounds in PM2.5 by Rapid Thermo-desorption Method Coupled with GC/MS].

Non-polar organic compounds (NPOCs) associated with PM2.5 in the atmosphere were analyzed by automated thermo-desorption (TD) coupled with gas chromatography/mass spectrometry (TD-GC/MS). The analyses for a total of 72 NPOCs were reviewed, including 34 PAHs, one Debenzothiophene, 27 alkanes (C10-C34), 5 hopanes and 5 steranes. Through this improved TD method, operation of filter loadings, TD condition and sample introduction were optimized. The MDL were 0.01-1.0, 0.1-8.0 and 0.50-2.0 ng·m-3 for PAHs, alkanes, hopanes and steranes, respectively. Calibration curve linearities were above 0.9 for all compounds. The TD efficiencies were 95%-100% for PAHs, 81%-100% for alkanes and 83.1%-100% for hopanes and steranes. PM2.5 samples were pretreated by TD and ultrasonic extraction methods separately and analyzed by GC/MS in two laboratories. Results from these two methods were comparable, as the relative biases were less than 30% for most compounds. Analysis results of PM2.5 samples from Linan and Shanghai showed that NPOCs were higher in winter than that in summer. Alkanes were predominant among NPOCs, followed by PAHs. Source analysis by PAH characteristic ratios indicated that fossil fuel burning and coal burning were the main sources of NPOCs in the two sites during the sampling periods.

[Estimation of Fine Particle (PM2.5) Emission Inventory from Cooking: Case Study for Shanghai].

Cooking is one of important emission sources of fine particles (PM2.5). This study using the catering enterprises of Shanghai as an example, presents a method to estimate the PM2.5 emission inventory from cooking according to the number of stoves, cooking time, and number of customers. Based on in situ measurements, the concentrations of PM2.5 emissions ranged from 0.1 mg ·m-3 to 1.8 mg ·m-3, which exceeded the limit (1.0 mg ·m-3 for lampblack) in the national standard. Organic carbon dominated the PM2.5 emitted from cooking, accounting for more than 50%. Extremely high ratios of organic carbon to elemental carbon were observed, ranging from 58.8 to 752.3, which could be used as an indicator of cooking emissions. The emission factors of PM2.5 in the catering industry are closely related to the scale of the catering enterprises. The emission factors of large-and medium-sized enterprises are obviously higher than those of small and micro enterprises. The PM2.5 emissions of catering enterprises are mainly attributed to high emission loads of large enterprises and those for a large number of small and medium enterprises. The PM2.5 emission inventory of cooking in Shanghai was calculated according to the three emission factors above, and the results were very close. Therefore, the method for estimating the PM2.5 emission inventory for cooking presented in this study is helpful for other Chinese cities to calculate their PM2.5 emission inventory from cooking.

[Physiochemical Properties of the Aerosol Particles and Their Impacts on Secondary Aerosol Formation at the Background Site of the Yangtze River Delta].

The study of the sources, compositions, and formation mechanisms of pollutants at the background site is crucial for the understanding of episodic events in the Yangtze River Delta (YRD). Secondary species are major components of PM2.5 particles. In this work, the compositions and concentrations of organic matter and secondary organic aerosol (SOA) at a background site of the YRD region were determined. The acidity and liquid water content of aerosol particles were modeled to investigate the impact of the physicochemical properties of aerosol particles on the formation of secondary species. The annual mean PM2.5 concentration in Chunan is 33 µg·m-3, with major contributions from inorganic sulfate (19%), nitrate (15%), ammonium (12%), and organic matter (19%). Nitrate is mainly locally formed, while sulfate is more affected by regional transport, except in winter. We found that the particles at the background site of the YRD have a high acidity and no seasonal variation was observed. The SOA formation at the background site of the YRD is enhanced by the liquid water content of the aerosol in spring, while it is more affected by the concentration of the oxidant, that is, O3, in summer. The contribution of SOA to PM2.5 in summer is as high as 40%.

[Chemical Characterization, Spatial Distribution, and Source Identification of Organic Matter in PM2.5 in summertime Shanghai, China].

Particulate organic matter (POM) has attracted increasing attention recently due to its great contribution to fine particles (PM2.5) and complex components and sources. In the present study, 78 particulate organic compounds in PM2.5 were quantified at three sites in Shanghai during summer; these sites were located in urban (Xuhui), suburban (Qingpu), and coastal (Lin'gang) areas of the city. Accordingly, the chemical composition and spatial distribution were investigated and sources were explored based on the indicators and diagnostic ratios combined with backward trajectory. The results showed that during the period of observation, the quantified organic matter in the suburban area is about 319 ng ·m-3, close to the urban area but much higher than that of the coastal areas. Fatty acids were the largest contributors, followed by levoglucosan, polycyclic aromatic hydrocarbons (PAHs), n-alkanes, and hopanes. Source analysis based on tracer methods indicates that gasoline vehicle emissions were the main source of POM in Shanghai. Biomass burning from the northeast impacted somewhat on the urban area and western suburbs during the observation period. Terrestrial plant emissions played an important role in the source of fatty acids at Qingpu and Lin'gang, and emissions of marine phytoplankton and microorganisms were also important for fatty acids at Lin'gang. Coal combustion and motor vehicle exhaust made an important contribution to PAHs according to an analysis of diagnostic ratios. This study presented the characteristics and sources of POM in summertime Shanghai, which facilitates the development of an effective control strategy on PM2.5 pollution.

Degradation of azo dye Acid black 1 using low concentration iron of Fenton process facilitated by ultrasonic irradiation.

A combination of ultrasonic and low concentration iron (<3 mgL(-1)) of Fenton process (US/Fenton) has been used to treat wastewater containing Acid black 1 (AB1). The results show that the oxidation power of low concentration iron of Fenton could be significantly enhanced by ultrasonic irradiation. The degradation of AB1 in aqueous solution by US/Fenton can receive better results compared with either Fenton oxidation or ultrasonic alone. Many operational parameters, such as ultrasonic power density, the pH value, the Fe(2+) dosage, the H(2)O(2) dosage, AB1 concentration and the temperature, affecting the degradation efficiency were investigated. Also, the effects of various inorganic anions (such as Cl(-), NO(3)(-), CO(3)(2-), etc.) on the oxidation efficiency of US/Fenton were studied. Under the given test conditions, 98.83% degradation efficiency was achieved after 30 min reaction by US/Fenton. The effect of various inorganic anions was in the following decreasing order: SO(3)(2-)>CH(3)COO(-)>Cl(-)>CO(3)(2-)>HCO(3)(-)>SO(4)(2-)>NO(3)(-). The results show that the US/Fenton can be an effective technology for the treatment of organic dyes in wastewater.

A kinetic study on the degradation of p-nitroaniline by Fenton oxidation process.

A detailed kinetic model was developed for the degradation of p-nitroaniline (PNA) by Fenton oxidation. Batch experiments were carried out to investigate the role of pH, hydrogen peroxide and Fe(2+) levels, PNA concentration and the temperature. The kinetic rate constants, k(ap), for PNA degradation at different reaction conditions were determined. The test results show that the decomposition of PNA proceeded rapidly only at pH value of 3.0. Increasing the dosage of H(2)O(2) and Fe(2+) enhanced the k(ap) of PNA degradation. However, higher levels of H(2)O(2) also inhibited the reaction kinetics. The k(ap) of PNA degradation decreased with the increase of initial PNA concentration, but increased with the increase of temperature. Based on the rate constants obtained at different temperatures, the empirical Arrhenius expression of PNA degradation was derived. The derived activation energy for PNA degradation by Fenton oxidation is 53.96 kJ mol(-1).

[Transport Loss Estimation of Fine Particulate Matter in Sampling Tube Based on Numerical Computation].

In-situ measurement of PM2.5 physical and chemical properties is a substantial approach for the mechanism investigation of PM2.5 pollution. Minimizing PM2.5 transport loss in sampling tube is essential for ensuring the accuracy of the measurement result. In order to estimate the integrated PM2.5 transport efficiency in sampling tube and optimize tube designs, the effects of different tube factors (length, bore size and bend number) on the PM2.5 transport were analyzed based on numerical computation. The results showed that PM2.5 mass concentration transport efficiency of vertical tube with flow rate at 20.0 L·min-1, bore size at 4 mm, length at 1.0 m was 89.6%. However, the transport efficiency increased to 98.3% when the bore size increased to 14 mm. PM2.5 mass concentration transport efficiency of horizontal tube with flow rate at 1.0 L·min-1, bore size at 4 mm, length at 10.0 m was 86.7%, and increased to 99.2% with length at 0.5 m. Low transport efficiency of 85.2% for PM2.5 mass concentration was estimated in bend with flow rate at 20.0 L·min-1, bore size at 4 mm, curvature angle at 90°. Laminar flow of air in tube through keeping the ratio of flow rate (L·min-1) and bore size (mm) below 1.4 was beneficial to decrease the PM2.5 transport loss. For the target of PM2.5 transport efficiency higher than 97%, it was advised to use vertical sampling tubes with length less than 6.0 m for the flow rates of 2.5, 5.0, 10.0 L·min-1 and bore size larger than 12 mm for the flow rates of 16.7 or 20.0 L·min-1. For horizontal sampling tubes, tube length was decided by the ratio of flow rate and bore size. Meanwhile, it was suggested to decrease the amount of the bends in tube of turbulent flow.