Characteristics of PM_(2.5) and Its Reactive Oxygen Species in Heating Energy Transition and Estimation of Its Impact on the Environment and Health in China——A Case Study in the Fenwei Plain

To reduce the adverse effects of traditional domestic solid fuel,the central government began implementing a clean heating policy in northern China in 2017.Clean coal is an alternative low-cost fuel for rural households at the present stage.In this study,18 households that used lump coal,biomass,and clean coal as the main fuel were selected to evaluate the benefits of clean heating transformation in Tongchuan,an energy city in the Fenwei Plain,China.Both indoor and personal exposure(PE)samples of fine particulate matter(PM_(2.5))were synchronically collected.Compared with the lump coal and biomass groups,the indoor PM_(2.5)concentration in the clean coal group is 43.6%and 20.0%lower,respectively,while the values are 16.8%and 21.3%lower,respectively,in the personal exposure samples.PM_(2.5)-bound elements Cd,Ni,Zn,and Mn strongly correlated with reactive oxygen species(ROS)levels in all fuel groups,indicating that transition metals are the principal components to generate oxidative stress.Using a reliable estimation method,it is predicted that after the substitution of clean coal as a household fuel,the all-cause,cardiovascular,and respiratory disease that causes female deaths per year could be reduced by 16,6,and 3,respectively,in the lump coal group,and 22,8,and 3,respectively,in the biomass group.Even though the promotion of clean coal has led to impressive environmental and health benefits,the efficiencies are still limited.More environmental-friendly energy sources must be promoted in the rural regions of China.

Development and application of photocatalytic coating for roadside NO_(x) mitigation in Hong Kong

A facile chemical method for the development of photocatalytic coating products was proposed based on practical application perspective for the Hong Kong roadside nitrogen oxides(NO_(x))mitigation.TiO_(2)-based photocatalytic coating PC-C film with crystallized size of around 5–6 nm was synthesized with the peptization of H_(2)O_(2).The PC-C coating possesses a super-hydrophilicity surface and is proven to have a NO_(x)degradation rate of 46.8%with an optimum pH level of 7.In addition,the PC-C coating presents a promising photocatalytic NO_(x)degradation compared with other commercially available coating products and P25 when applied on two building materials of poly-methyl methacrylate(PMMA)and concrete surface.A weather resistance simulation and a 180-day on-site field trial were carried out the attenuation effects of photocatalytic coating applied in outdoor exposure.Based on epidemiological estimation and field investigation,hospital admissions for respiratory diseases(HARD)and mortality cases(MC)could be reduced with the application of PC-C coating along the street canyon.This work demonstrates the feasibility of air pollution control measures for the local roadside NO_(x)using photocatalytic technology,offering promising health benefits with environmental remediation.

Recent progress of MgO-based materials in CO_(2) adsorption and conversion:Modification methods,reaction condition,and CO_(2) hydrogenation

Integrated CO_(2) capture and conversion of(ICCC)is one of the most effective solutions to reduce anthropogenic CO_(2) emissions,which has attracted extensive public attention.Dual functional materials(DFMs),including adsorbent and catalyst,are the key components to achieve ICCC.Magnesium oxide(MgO)is an ideal adsorbent for ICCC,since it is characterized by high theoretical adsorption capacity,low cost,low energy consumption and extensive sources.It can also be used as DFMs in combination with the Ni catalysts.MgO not only can act as an adsorbent in DFMs but also enhance the catalytic performance of Ni.This review summarizes the advantages and modification methods of MgO as adsorbent and the influence of its adsorption conditions on the adsorption performance.Moreover,the important role of MgO in facilitating the catalytic conversion of CO_(2) is highlighted.Future research focuses are proposed for the development of MgO based DFMs with high adsorption capacity,high stability,conversion,and selectivity as well as low cost and energy consumption.

The new challenges for the development of NH_(3)-SCR catalysts under new situation of energy transition in power generation industry

NH_(3)-SCR was one of the most promising de NO_x technologies and it has been widely applied in industrial NO_x reduction.However,with the further development of energy transformation in power generation sector,the development of NH_(3)-SCR catalysts is facing some new challenges.It is becoming an urgent problem to solve low catalytic activity and stability of NH_(3)-SCR catalysts at the working condition of ultra-low temperature(≤200℃)and high concentrations of H_(2)O+SO_(2) due to the gradual deployment of new energy power plants.Furthermore,the traditional coal-fired power plants would need flexible operation with the increasing share of renewable energy generation.The NH_(3)-SCR catalysts which were applied in coal-fired power industry would be requested to work in a wide temperature window from 200℃ to 500℃ in the near future.Therefore,in this review,we summarized the progress of NH_(3)-SCR catalysts in solving these different industrial problems in recent years.And the research directions which were deserved to be focused on the development of NH_(3)-SCR catalysts for the energy transition of power generation sector are proposed.

New eolian red clay sequence on the western Chinese Loess Plateau linked to onset of Asian desertification about 25 Ma ago

The expansion of inland Asia deserts has considerably influenced the environmental, social and economic activities in Asia. Aridification of inland Asia, especially timing of the initiation of Asian desertification, is a contentious topic in paleoclimatology. Late Cenozoic eolian loess-red clay sequences on the Chinese Loess Plateau, which possess abundant paleoclimatic and paleo-environmental information, can be regarded as an indicator of inland Asia desertification. Here we present a detailed magnetostratigraphic investigation of a new red clay sequence about 654 m in Zhuanglang located at the western Chinese Loess Plateau. Sedimentological, geochemical, mineralogical, and quartz morphological lines of evidence show that the red clay is of eolian origin. Magnetostratigraphic correlations indicate that this core sequence spans from 25.6 to 4.8 Ma, and typical eolian red clay appears as early as 25 Ma. This extends the lower limit of the red clay on the Chinese Loess Plateau from the previously thought early Miocene back into the late Oligocene. This new red clay record further implies that the inland Asia desertification was initiated at least by the late Oligocene. This sequence provides a unique high-resolution geological record for understanding the inland Asia desertification process since the late Oligocene.

Chemical signature and fractionation of trace elements in fine particles from anthropogenic and natural sources

The health effects of trace metal elements in atmospheric fine particulate matter(PM_(2.5))are widely recognized,however,the emission factor profiles and chemical fractionation of metal elements in different sources were poorly understand.In this study,sixteen metal elements,including Cd,Pb,V,Zn,Ba,Sb,As,Fe,Sr,Cr,Rb,Co,Mn,Cu,Ni and Sn frombiomass burning,bituminite and anthracite combustion,as well as dust,were quantified.The results showdifferent emission sourceswere associated with distinct emission profiles,holding important implications for source apportionment of ambient particulate metals.Specifically,Fe was the dominant metal species(28-1922 mg/kg)for all samples,and was followed by different metals for different samples.For dust,Mn(39.9 mg/kg_(dust))had the second-highest emission factor,while for biomass burning,itwas Cr and Ba(7.5 and 7.4mg/kg_(biomass),respectively).For bituminous coal combustion,the emission factor of Zn and Ba was 6.2 and 6.0 mg/kg_(bituminous),respectively,while for anthracite combustion the corresponding emission factor was 5.6 and 4.3 mg/kg_(anthracite),respectively.Moreover,chemical fractionation(i.e.,the exchangeable,reducible fraction,oxidizable,and residual fraction)and the bioavailability index(BI)values of the metal elements from different sources were further investigated to reveal the link between different emission sources and the potential health risk.The findings from this study hold important implications for source apportionment and sourcespecific particulate metal-associated health effects.

Advances in catalytic elimination of atmospheric pollutants by two-dimensional transition metal oxides

Atmospheric pollutants can deteriorate air quality and put human health at risk.There is a growing need for green,economical,and efficient technologies,among which catalytic elimination technology is the most promising,to remove atmospheric pollutants.Two-dimensional transition metal oxides(2D TMOs)have recently become attractive catalysts due to their highly exposed active sites,excellent reactant transport properties,and extraordinary catalytic performance.This review systematically summarizes the topdown and bottom-up preparation methods of 2D TMOs and focuses on the specific applications of 2D TMOs in the catalytic elimination of atmospheric inorganic pollutants and volatile organic pollutants.The development of 2D TMOs in the catalytic elimination of atmospheric pollutants is prospected.This review is expected to provide design insights into efficient 2D TMOs to remove atmospheric pollutants.

Promoted surface charge density from interlayer Zn–N_(4) configuration in carbon nitride for enhanced CO_(2) photoreduction

The solar-driven reduction of CO_(2) into valuable products is a promising method to alleviate global environmental problems and energy crises.However,the low surface charge density limits the photocatalytic conversion performance of CO_(2).Herein,a polymeric carbon nitride(PCN)photocatalyst with Zn single atoms(Zn1/CN)was designed and synthesized for CO_(2) photoreduction.The results of the CO_(2) photoreduction studies show that the CO and CH_(4) yields of Zn1/CN increased fivefold,reaching 76.9 and 22.9μmol/(g·h),respectively,in contrast to the unmodified PCN.Ar+plasma-etched X-ray photoelectron spectroscopy and synchrotron radiation-based X-ray absorption fine structure results reveal that Zn single atom is mainly present in the interlayer space of PCN in the Zn–N_(4) configuration.Photoelectrochemical characterizations indicate that the interlayer Zn–N_(4) configuration can amplify light absorption and establish an interlayer charge transfer channel.Light-assisted Kelvin probe force microscopy confirms that more photogenerated electrons are delivered to the catalyst surface through interlayer Zn–N_(4) configuration,which increases its surface charge density.Further,in-situ infrared spectroscopy combined with density functional theory calculation reveals that promoted surface charge density accelerates key intermediates(*COOH)conversion,thus achieving efficient CO_(2) conversion.This work elucidates the role of internal single atoms in catalytic surface reactions,which provides important implications for the design of single-atom catalysts.

Recent progress on two-dimensional materials confining single atoms for CO_(2) photoreduction

Photoreduction of CO_(2) into value-added products offers a promising approach to overcome both climate change and energy crisis.However,low conversion efficiency,poor product selectivity,and unclear mechanism limit the further advancement of CO_(2) photoreduction.The development of two-dimensional(2D)materials and construction of single atom sites are two frontier research fields in catalysis.Combining the advantages of 2D materials and single atom sites is expected to make a breakthrough in CO_(2) photoreduction.In this review,we summarized the design and application,proposed challenges and opportunities,and laid a foundation for further research and application of 2D materials confining single atoms(SACs@2D)for CO_(2) photoreduction.