Publications by authors named "Xianbao Shen"

Black carbon (BC) poses acute negative health and environmental impacts. Accurate BC quantification is important for assessing its impacts and developing effective control strategies. However, the unclear optical properties and numerous methods of BC restrict its accurate quantification.

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  • - The study focuses on creating a database of volatile organic compound (VOC) emissions from motor vehicles to aid in air pollution control efforts, particularly for fine particulate matter (PM) and ozone (O) formation.
  • - Emissions from light-duty gasoline passenger vehicles (LDGPVs) mainly consist of alkanes and aromatics, while light-duty diesel trucks (LDDTs) primarily emit alkanes, and other vehicle types release a variety of oxygenated VOCs.
  • - The research notes a change in VOC composition due to updated emission standards and highlights specific compounds that need monitoring, helping to improve understanding of VOC emissions from different vehicle types and contributing to pollution prevention strategies.
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  • Non-road mobile machinery (NRMM) is increasingly contributing to black carbon (BC) emissions, yet its optical properties, specifically the mass absorption cross-section (MAC), remain poorly defined.
  • This study analyzed real-world measurements from 41 NRMM units and discovered that higher organic carbon to elemental carbon (OC/EC) ratios enhance BC light absorption, resulting in increased MAC values.
  • The research also indicates that stricter emission standards are linked to a notable decrease in MAC values, and it proposes a new MAC value of 11.5 ± 3.4 m/g for NRMM at a 550 nm wavelength, which is significantly higher than previously used values.
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Photocatalytic technology is regarded as a promising approach for fast degradation of refractory organic pollutant in water. However, the performance of the photocatalyst can be restricted by the variation of water matrix conditions. Herein, coconut shell fiber was pyrolyzed to biochar (CSB800) and incorporated with α-MnO to degrade bisphenol A (BPA) in water under visible light irradiation.

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  • * Diesel-based emission factors for these organics reveal a high percentage of volatile organic compounds (VOCs), and stricter emission standards have decreased these emissions, particularly during pesticide spraying activities.
  • * The study estimates that NRAM emitted approximately 94.23 Gg of full-volatility organics in 2021, providing crucial data to enhance emission inventories and improve atmospheric chemistry models.
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  • - This study analyzed the emissions of 120 different volatile organic compounds (VOCs) from 40 types of nonroad machines, finding that diesel engines emit an average of 4.18 g of VOCs per kg of fuel, mainly consisting of alkanes and oxygenated VOCs.
  • - Various factors such as machine type, power rating, and operating conditions influenced VOC emissions, with combustion efficiency being a key determinant.
  • - The research highlighted the significant potential for these VOCs to form secondary organic aerosols and ozone, suggesting that targeting specific VOC species could effectively reduce air pollution from nonroad mobile sources, particularly in China's construction and agricultural sectors.
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Heterogeneous iron/persulfate system suffers from the problems of high ion leaching, severe catalyst surface corrosion and low performance stability. Herein, a series of iron compound incorporated N doped biochar composite catalysts were prepared from pyrolyzing wood powder and ferric ferrocyanide mixture, which were used for bisphenol A (BPA) degradation in water through peroxymonosulfate (PMS) activation. It was found that the reducing gases released from wood powder at different pyrolysis temperature significantly affected the crystalline phase of the iron compound in the catalyst, in which pure phase iron carbide (FeC) decorated N doped biochar was obtained at pyrolysis temperature of 600 °C or higher.

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  • Cooking produces harmful volatile organic compounds (VOCs) that can affect both the environment and human health, with emissions varying significantly across different cuisines.* -
  • The study measured VOC emissions from various cuisines, finding barbecue emitted the highest levels while family cuisine had the lowest, with ethanol and alkanes being the dominant compounds in most cuisines.* -
  • Results indicated that photocatalytic oxidation was the most effective method for reducing VOC emissions, while other techniques like wet purification and mechanical separation were less effective or counterproductive.*
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  • The study focuses on characterizing emissions of semivolatile and intermediate-volatility organic compounds (S/IVOCs) from nonroad construction machines (NRCMs) in China, which has previously been under-researched.
  • Researchers evaluated 21 NRCMs using a portable emission measurement system and found that loaders emitted higher average IVOC and SVOC factors compared to excavators, with operating modes influencing these emissions.
  • The findings indicate that improvements in emission regulations have successfully reduced emissions from NRCMs, particularly excavators, with IVOCs being major contributors to secondary organic aerosol (SOA) production, showcasing the significance of controlling these emissions for environmental health.
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  • Emissions of carbonyl compounds from agricultural machines are significant as they contribute to ozone formation and photochemical smog, with key compounds including formaldehyde and acetaldehyde.
  • A study of 20 agricultural machines measured their exhaust emissions using portable equipment, revealing varying carbonyl emission factors based on China's emission standards, with higher emissions observed from older machines.
  • The potential for ozone formation (OFP) was notably higher during seed sowing compared to other operations, indicating that agricultural processes can greatly impact air quality, with total emissions from these machines in China recorded at 19.23 Gg in 2019.
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  • Black carbon (BC) emissions from agricultural machinery (AM) in China are significant but not well understood, prompting a study that measured BC emissions and factors during different tillage processes.
  • The research reveals diverse BC emission factors (EFs) influenced by the type of tillage and emission standards, showing that newer machinery (China III standards) significantly lowers emissions compared to older models (China II standards).
  • The study estimates varying emission levels of BC and CO during corn and wheat production, highlighting the potential for reducing overall emissions from AM and emphasizing the need for better emission control strategies.
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  • Non-road construction equipment (NRCE) contributes significantly to urban air pollution, but research on its emissions is still limited.
  • A study measuring emissions from excavators and loaders found that emission rates varied widely based on operation modes, with high emissions during cold starts.
  • The effectiveness of tightening emission standards has generally reduced multi-pollutant emissions, though CO and NOx levels remain problematic, highlighting differences between engine types and the need for more accurate emission factors for NRCE.
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The rapid reproduction of foodborne bacteria in food packaging threatens the health of consumers, the massive use and waste of packaging also causes serious environmental pollution. In this study, novel biodegradable antibacterial membranes based on silver-modified carboxymethyl chitosan (Ag-CMCS) were prepared. Polylactic acid (PLA) and polybutylene adipate-co-terephthalate (PBAT) were used as the base membrane materials.

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Urban green spaces (UGSs) are often positively associated with the health of urban residents. However, UGSs may also have adverse health effects by releasing biogenic volatile organic compounds (BVOCs) and increasing the ambient concentrations of ozone (O) and secondary organic aerosols in urban areas. BVOC emissions from UGSs might be underestimated because of the lack of consideration of the UGS land-use type in urban areas.

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Predicting spatial explicit information of soil nutrients is critical for sustainable soil management and food security under climate change and human disturbance in agricultural land. Digital soil mapping (DSM) techniques can utilize soil-landscape information from remote sensing data to predict the spatial pattern of soil nutrients, and it is important to explore the effects of remote sensing data types on DSM. This research utilized Landsat 8 (LT), Sentinel 2 (ST), and WorldView-2 (WV) remote sensing data and employed partial least squares regression (PLSR), random forest (RF), and support vector machine (SVM) algorithms to characterize the spatial pattern of soil total nitrogen (TN) in smallholder farm settings in Yellow River Basin, China.

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Although ion exchange resins (IERs) have been extensively adopted in water treatment, there are no reports on the application thereof for synthesizing antibacterial materials against pathogenic bacteria. The present study is the first in which the ion exchange characteristic of IERs was utilized to introduce silver ions that possess efficient antibacterial properties. The resulting antibacterial materials were incorporated into polylactic acid (PLA) and/or polybutylene adipate terephthalate (PBAT) to prepare antibacterial membranes.

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  • This study investigates the connections between instantaneous black carbon (BC) emissions and driving behaviors of diesel trucks (DTs) to improve vehicle emissions estimation systems.
  • Measurements were taken from 22 real-world diesel trucks to analyze black carbon emissions in relation to vehicle specific power (VSP), fuel consumption, and emission factors (EFs).
  • The findings reveal that BC emissions are significantly lower for trucks with diesel particulate filters, and fluctuations in VSP and EFs were observed, leading to established formulas for better emission quantification.
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In order to reduce foodborne diseases caused by bacterial infections, antibacterial membranes have received increasing research interests in recent years. In this study, highly effective antibacterial membranes were prepared using biodegradable polymers, including polylactic acid (PLA), polybutylene adipate terephthalate (PBAT), and carboxymethyl cellulose (CMC). The cation exchange property of CMC was utilized to introduce silver to prepare antibacterial materials.

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  • Non-road construction equipment (NRCE) in China contributes significantly to urban air pollution, particularly through emissions of black carbon (BC) from diesel engines, impacting climate, visibility, and health.
  • This study involved measurements of BC emissions from 12 excavators and 9 loaders, revealing that factors like operation mode, emission standards, and engine power significantly influence BC emissions.
  • The results show that stricter emission standards lead to lower BC emissions from NRCE, with the study providing recommendations for BC emission factors that can help improve emission inventories and address pollution concerns.
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In order to make clear the role of intercalated anions in layered double hydroxides (LDHs) for catalytic hydrolysis of carbonyl sulfide (COS), the adsorption and reaction characteristics of COS over the simple MgAl-Cl-LDH model catalyst were studied by both theoretical and experimental methods. Density functional theory (DFT) calculations by CASTEP found that the chloride ions in LDH function as the key Brønsted base sites to activate the adsorbed HO with enlarged bond length and angle, facilitate the dissociative adsorption of intermediates including mono-thiocarbonic acid (MTA) and hydrogen thiocarbonic acid (HTA), and participate in the formation of transient states and subsequent hydrogen transfer process with decreased energy barriers during COS hydrolysis. COS hydrolysis will preferentially go through the dissociated intermediates of mono-thiocarbonates (MT) and hydrogen thiocarbonates (HT) with dramatically decreased energy barriers, and the rate-determining step of COS hydrolysis over MgAl-Cl-LDH will be the nucleophilic addition of C=O in COS by HO (Ea = 1.

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Ion exchange membranes (IEMs) are widely used in water treatment applications such as electrodialysis. However, the exploration of IEMs as effective antibacterial food contact materials (e.g.

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A rapid reaction occurs near the exhaust nozzle when vehicle emissions contact the air. Twenty diesel vehicles were studied using a new multipoint sampling system that is suitable for studying the exhaust plume near the exhaust nozzle. The variation characteristics of fine particle matter (PM) and its components in diesel vehicle exhaust plumes were analyzed.

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Diesel vehicle is an important source of black carbon (BC). A portable emission measurement system including a photo-acoustic extinctiometer and SEMTECH-LDV was used to measure the real-world emissions of 14 light-duty and heavy-duty diesel trucks (LDDTs and HDDTs, meeting the China IV and China V standards) in Beijing. BC emission factors and the BC/PM ratio were obtained, and the effects of the vehicle type, emission standard and driving cycle on emissions were analyzed.

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Black carbon (BC) as an important part of atmospheric aerosols imposes adverse effects on atmospheric visibility, health, and climate change. Mass absorption cross-section (MAC) is an essential parameter in BC quantitative and model research, which is of growing concern in recent decades. In this study, we conducted real-world measurements on BC emissions from two major sources of residential biofuel stoves and diesel trucks.

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Humans are more likely to be exposed to ultrafine particles (UFPs) emitted by light-duty gasoline vehicles (LDGVs) in urban road traffic, which can cause serious bodily harm. In this study, we conducted on-road measurement of the Particle Number (PN) emissions from 18 China-3, China-4, and China-5 LDGVs on representative roads in Beijing. To clarify the impact of key parameters (standards, driving conditions, and technology) on the PN emissions, we conducted a comprehensive analysis of the emission results.

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