Dissolved organic matter(DOM)is ubiquitous in the environment and plays an important role in global ecosystems.However,our understanding of the evolution and molecular diversity of DOM from different biomass materials...Dissolved organic matter(DOM)is ubiquitous in the environment and plays an important role in global ecosystems.However,our understanding of the evolution and molecular diversity of DOM from different biomass materials and biochar is not enough.Herein,we investigated the changes in DOM from seven biomass and biochar samples over a bio-incubation of 28 days,and explored their contents,and optical,chemical,and molecular characteristics.The results indicated that dissolved organic carbon(DOC)from different sources all exhibited a gradually decreasing trends during the incubation,while the absorbance and aromaticity gradually increased.Biomass DOM was characterized by higher DOC concentrations and a higher degradation rate,whereas biochar DOM had high aromaticity and little variability.Parallel factor analysis results showed that the protein-like fluorescent groups were as only detected in biomass DOM,while the dominant humic-like components were identified in biochar DOM.Additionally,the molecular composition of DOM from different sources was different,and biomass DOM contained more carbohydrate-like and saturated compounds.More sulfur-containing compounds were detected in Ceratophyllum demersum(CD)DOM,which may indicate that the leaching of CD litter was an important source of sulfur-containing species in aquatic environments.Furthermore,biochar DOM had greater aromaticity and a higher degree of oxidation than the corresponding biomass DOM.This study provided a detailed understanding of the molecular diversity of DOM by considering its various sources,and the results are helpful for further understanding their chemical properties and structures.展开更多
Nitrogen-containing organic compounds(NOCs)may potentially contribute to aqueous secondary organic aerosols,yet the different formation of NOCs in aerosol particles and cloud droplets remains unclear.With the in-situ ...Nitrogen-containing organic compounds(NOCs)may potentially contribute to aqueous secondary organic aerosols,yet the different formation of NOCs in aerosol particles and cloud droplets remains unclear.With the in-situ measurements performed at a mountain site(1690 m a.s.l.)in southern China,we investigated the formation of NOCs in the cloud droplets and the cloud-free particles,based on their mixing state information of NOCscontaining particles by single particle mass spectrometry.The relative abundance of NOCs in the cloud-free particles was significantly higher than those in cloud residual(cloud RES)particles.NOCs were highly correlated with carbonyl compounds(including glyoxalate and methylglyoxal)in the cloud-free particles,however,limited correlation was observed for cloud RES particles.Analysis of their mixing state and temporal variations highlights that NOCs was mainly formed from the carbonyl compounds and ammonium in the cloud-free particles,rather than in the cloud RES particles.The results support that the formation of NOCs from carbonyl compounds is facilitated in concentrated solutions in wet aerosols,rather than cloud droplets.In addition,we have identified the transport of biomass burning particles that facilitate the formation of NOCs,and that the observed NOCs is most likely contributed to the light absorption.These findings have implications for the evaluation of NOCs formation and their contribution to light absorption.展开更多
The impact of reducing industrial emissions of volatile organic compounds(VOCs)on ozone(O_(3))pollution is of wide concern particularly in highly industrialized megacities.In this study,O_(3),nitrogen oxides(NOx)and V...The impact of reducing industrial emissions of volatile organic compounds(VOCs)on ozone(O_(3))pollution is of wide concern particularly in highly industrialized megacities.In this study,O_(3),nitrogen oxides(NOx)and VOCs were measured at an urban site in the Pearl River Delta region during the 2018 Chinese National Day Holidays and two after-holiday periods(one with ozone pollution and another without).O_(3)pollution occurred throughout the 7-day holidays even industrial emissions of VOCswere passively reduced due to temporary factory shutdowns,and the toluene to benzene ratios dropped from∼10 during non-holidays to∼5 during the holidays.Box model(AtChem2-MCM)simulations with the input of observation data revealed that O_(3)formation was all VOC-limited,and alkenes had the highest relative incremental reactivity(RIR)during the holiday and non-holiday O_(3)episodes while aromatics had the highest RIR during the non-pollution period.Box model also demonstrated that even aromatics decreased proportionally to levels with near-zero contributions of industrial aromatic solvents,O_(3)concentrations would only decrease by less than 20%during the holiday and non-holiday O_(3)episodes and ozone pollution in the periods could not be eliminated.The results imply that controlling emissions of industrial aromatic solvents might be not enough to eliminate O_(3)pollution in the region,and more attention should be paid to anthropogenic reactive alkenes.Isoprene and formaldehyde were among the top 3 species by RIRs in all the three pollution and non-pollution periods,suggesting substantial contribution to O_(3)formation from biogenic VOCs.展开更多
Chemical speciation of fine particles or PM2.5 collected on filters is still a cosily and time- consuming task. In this study, filter-based PM2.5 samples were collected during November-December 2013 at four sites in G...Chemical speciation of fine particles or PM2.5 collected on filters is still a cosily and time- consuming task. In this study, filter-based PM2.5 samples were collected during November-December 2013 at four sites in Guangzhou, and the major components were fast screened （~ 7 rain per filter sample） by Attenuated Total Reflectance （ATR）-Fourier Transform Infrared Spectroscopic （FTIR） in comparison with that measured by Organic carbon/Element carbon （OC/ EC） analyzer and Ion Chromatography （IC）. The concentrations of nitrate, ammonium, sulfate, primary organic carbon （POC） and secondary organic carbon （SOC） measured by OC/EC and IC analyzers were better correlated with their infrared absorption peak heights at 1320 cm 1 for nitrate, 1435, 3045 and 3215 cm^-1 for ammonium, 615 cm^-1 for sulfate, 690, 760 and 890 cm^-1 for POC and 1640 and 1660 cm^-1 for SOC respectively, during polluted days （PM2.5 〉 75 μg/m^3） than during clean days （PM2.5〈 75 μg/m^3）. With the evolution of a haze episode during our field campaign, the concentrations of the major PM2.5 components displayed consistent variations with their infrared absorption peak heights, suggesting ATR-FTIR could be a fast and useful technique to characterize filter-based PM2.5 compositions particularly during pollution events although cautions should be taken when PM2.5 levels are low. Notably, elevated PM2.5 mass concentrations occurred with enhanced ratios of [NO^-3][SO^2-4] and [NH^＋4]/[SO^2-4], implying that nitrogenous components play vital roles in the PM2.5 pollution events in the study region.展开更多
Formaldehyde(HCHO)and glyoxal(CHOCHO)are important oxidization intermediates of most volatile organic compounds(VOCs),but their vertical evolution in urban areas is not well understood.Vertical profiles of HCHO,CHOCHO...Formaldehyde(HCHO)and glyoxal(CHOCHO)are important oxidization intermediates of most volatile organic compounds(VOCs),but their vertical evolution in urban areas is not well understood.Vertical profiles of HCHO,CHOCHO,and nitrogen dioxide(NO_(2))were retrieved from ground-based Multi-Axis Differential Optical Absorption Spectroscopy(MAXDOAS)observations in Hefei,China.HCHO and CHOCHO vertical profiles prefer to occur at higher altitudes compared to NO_(2),which might be caused by the photochemistry-oxidation of longer-lived VOCs at higher altitudes.Monthly means of HCHO concentrations were higher in summer,while enhanced amounts of NO_(2)were mainly observed in winter.CHOCHO exhibited a hump-like seasonal variation,with higher monthly-averaged values not only occurred in warm months(July-August)but also in cold months(November-December).Peak values mainly occurred during noon for HCHO but emerged in the morning for CHOCHO and NO_(2),suggesting that HCHO is stronger link to photochemistry than CHOCHO.We further use the glyoxal to formaldehyde ratio(GFR)to investigate the VOC sources at different altitudes.The lowest GFR value is almost found in the altitude from 0.2 to 0.4 km,and then rises rapidly as the altitude increases.The GFR results indicate that the largest contributor of the precursor VOC is biogenic VOCs at lower altitudes,while at higher altitudes is anthropogenic VOCs.Our findings provide a lot more insight into VOC sources at vertical direction,but more verification is recommended to be done in the future.展开更多
Mineral dust,soil,and sea salt aerosols are among the most abundant primary inorganic aerosols in the atmosphere,and their hygroscopicity affects the hydrological cycle and global climate.We investigated the hygroscop...Mineral dust,soil,and sea salt aerosols are among the most abundant primary inorganic aerosols in the atmosphere,and their hygroscopicity affects the hydrological cycle and global climate.We investigated the hygroscopic behaviors of six Na-and K-containing salts commonly found in those primary organic aerosols.Their hygroscopic growths as a function of relative humidity(RH) agree well with thermodynamic model prediction.Temperature dependence of deliquescence RH(DRH) values for five of those salts was also investigated,which are comparable to those in literature within 1%-2% RH,most showing negative dependence on temperature.Hygroscopic growth curves of real-world soil and sea salt samples were also measured.The hygroscopic growths of two more-hydroscopic saline soil samples and of sea salt can be predicted by the thermodynamic model based on the measured water-soluble ionic composition.The substantial amounts of water-soluble ions,including Na+and K+,in saline soil samples imply that even nascent saline soil samples are quite hygroscopic at high-RH(>80%) conditions.For three less-hygroscopic dust samples,however,measurements showed higher water uptake ability than that predicted by the thermodynamic model.The small amount of water taken up by less-hygroscopic dust samples suggests that dust particles might contain thin layers of water even to very low RH.The results of this study provide a comprehensive characterization of the hygroscopicity of Na-and K-containing salts as related to their roles in the hygroscopic behaviors of saline mineral dusts and sea salt aerosols.展开更多
Heterogeneous reaction of NO_(2) with mineral dust aerosol may play important roles in troposphere chemistry,and has been investigated by a number of laboratory studies.However,the influence of mineralogy on this reac...Heterogeneous reaction of NO_(2) with mineral dust aerosol may play important roles in troposphere chemistry,and has been investigated by a number of laboratory studies.However,the influence of mineralogy on this reaction has not been well understood,and its impact on aerosol hygroscopicity is not yet clear.This work investigated heterogeneous reactions of NO_(2)(∼10 ppmv)with K-feldspar,illite,kaolinite,montmorillonite and Arizona Test Dust(ATD)at room temperature as a function of relative humidity(<1%to 80%)and reaction time(up to 24 hr).Heterogeneous reactivity towards NO_(2) was low for illite,kaolinite,montmorillonite and ATD,and uptake coefficients of NO_(2),γ(NO_(2)),were determined to be around or smaller than 1×10^(−8);K-feldspar exhibited higher reactivity towards NO_(2),and CaCO_(3) is most reactive among the nine mineral dust samples considered in this and previous work.After heterogeneous reaction with NO_(2) for 24 hr,increase in hygroscopicity was nearly insignificant for illite,kaolinite and montmorillonite,and small but significant for K-feldspar;in addition,large increase in hygroscopicity was observed for ATD,although the increase in hygroscopicity was still smaller than CaCO_(3).展开更多
Mineral dust is an important type of ice nucleating particles in the troposphere;however,the effects of heterogeneous reactions on ice nucleation(IN)activities of mineral dust remain to be elucidated.A droplet-freezin...Mineral dust is an important type of ice nucleating particles in the troposphere;however,the effects of heterogeneous reactions on ice nucleation(IN)activities of mineral dust remain to be elucidated.A droplet-freezing apparatus(Guangzhou Institute of Geochemistry Ice Nucleation Apparatus,GIGINA)was developed in thiswork to measure IN activities of atmospheric particles in the immersion freezingmode,and its performancewas validated by a series of experimental characterizations.This apparatus was then employed to measure IN activities of feldspar and Arizona Test Dust(ATD)particles before and after heterogeneous reaction with NO_(2)(10±0.5 ppmv)at 40%relative humidity.The surface coverage of nitrate,θ(NO_(3)^(−)),increased to 3.1±0.2 for feldspar after reaction with NO_(2) for 6 hr,and meanwhile the active site density per unit surface area(ns)at-20℃ was reduced from 92±5 to<1.0 cm^(−2) by about two orders of magnitude;however,no changes in nitrate content or IN activities were observed for further increase in reaction time(up to 24 hr).Both nitrate content and IN activities changed continuously with reaction time(up to 24 hr)for ATD particles;after reaction with NO_(2) for 24 hr,θ(NO_(3)^(−))increased to 1.4±0.1 and ns at-20℃ was reduced from 20±4 to 9.7±1.9 cm^(−2) by a factor of∼2.Our work suggests that heterogeneous reaction with NO_(2),an abundant reactive nitrogen species in the troposphere,may significantly reduce IN activities of mineral dust in the immersion freezing mode.展开更多
n-Hexane is widely used in industrial production as an organic solvent. As an industrial exhaust gas, the contribution of n-hexane to air pollution and damage to human health are attracting increasing attention. In th...n-Hexane is widely used in industrial production as an organic solvent. As an industrial exhaust gas, the contribution of n-hexane to air pollution and damage to human health are attracting increasing attention. In the present study, aqueous solutions of two fluorocarbon surfactants（FSN100 and FSO100） were investigated for their properties of solubilization and dynamic absorption of n-hexane, as well as their capacity for regeneration and n-hexane recovery by thermal distillation. The results show that the two fluorocarbon surfactants enhance dissolution and absorption of n-hexane, and their effectiveness is closely related to their concentrations in solution. For low concentration solutions（0.01%–0.30%）, the partition coefficient decreases dramatically and the saturation capacity increases significantly with increasing concentration, but the changes for both are more modest when the concentration is over 0.30%. The FSO100 solution presents a smaller partition coefficient and a greater saturation capacity than the FSN100 solution at the same concentration,indicating a stronger solubilization for n-hexane. Thermal distillation is a feasible method to recover n-hexane from these absorption solutions, and to regenerate them. With 90 sec heating at 80–85°C, the recovery of n-hexane ranges between 81% and 85%, and the regenerated absorption solution maintains its original performance during reuse. This study provides basic information on two fluorocarbon surfactants for application in the treatment of industrial n-hexane waste gases.展开更多
Thermodynamic modeling is still themostwidely usedmethod to characterize aerosol acidity,a critical physicochemical property of atmospheric aerosols.However,it remains unclear whether gas-aerosol partitioning should b...Thermodynamic modeling is still themostwidely usedmethod to characterize aerosol acidity,a critical physicochemical property of atmospheric aerosols.However,it remains unclear whether gas-aerosol partitioning should be incorporated when thermodynamicmodels are employed to estimate the acidity of coarse particles.In this work,field measurements were conducted at a coastal city in northern China across three seasons,and covered wide ranges of temperature,relative humidity and NH_(3) concentrations.We examined the performance of different modes of ISORROPIA-II(a widely used aerosol thermodynamic model)in estimating aerosol acidity of coarse and fine particles.The M0 mode,which incorporates gas-phase data and runs the model in the forward mode,provided reasonable estimation of aerosol acidity for coarse and fine particles.Compared to M0,the M1 mode,which runs the model in the forward mode but does not include gas-phase data,may capture the general trend of aerosol acidity but underestimates pH for both coarse and fine particles;M2,which runs the model in the reverse mode,results in large errors in estimated aerosol pH for both coarse and fine particles and should not be used for aerosol acidity calculations.However,M1 significantly underestimates liquid water contents for both fine and coarse particles,while M2 provides reliable estimation of liquid water contents.In summary,our work highlights the importance of incorporating gas-aerosol partitioning when estimating coarse particle acidity,and thus may help improve our understanding of acidity of coarse particles.展开更多
The acidity of atmospheric aerosols influences fundamental physicochemical processes that affect climate and human health.We recently developed a novel and facilewater-probebased method for directly measuring of the p...The acidity of atmospheric aerosols influences fundamental physicochemical processes that affect climate and human health.We recently developed a novel and facilewater-probebased method for directly measuring of the pH for micrometer-size droplets,providing a promising technique to better understand aerosol acidity in the atmosphere.The complex chemical composition of fine particles in the ambient air,however,poses certain challenges to using a water-probe for pH measurement,including interference from interactions between compositions and the influence of similar compositions on water structure.To explore the universality of our method,it was employed to measure the pH of ammonium,nitrate,carbonate,sulfate,and chloride particles.The pH of particles covering a broad range(0–14)were accurately determined,thereby demonstrating that our method can be generally applied,even to alkaline particles.Furthermore,a standard spectral library was developed by integrating the standard spectra of common hydrated ions extracted through the waterprobe.The library can be employed to identify particle composition and overcome the spectral overlap problem resulting from similar effects.Using the spectral library,all ions were identified and their concentrations were determined,in turn allowing successful pH measurement of multicomponent(ammonium-sulfate-nitrate-chloride)particles.Insights into the synergistic effect of Cl^(–),NO_(3)^(–),and NH_(4)^(+)depletion obtained with our approach revealed the interplay between pH and volatile partitioning.Given the ubiquity of component partitioning and pH variation in particles,the water probemay provide a new perspective on the underlying mechanisms of aerosol aging and aerosol–cloud interaction.展开更多
As important precursors of ozone(O_(3))and secondary organic aerosol(SOA),reactive aromatic hydrocarbons(AHs)have typically been classified as anthropogenic air pollutants.However,biogenic emission can also be a poten...As important precursors of ozone(O_(3))and secondary organic aerosol(SOA),reactive aromatic hydrocarbons(AHs)have typically been classified as anthropogenic air pollutants.However,biogenic emission can also be a potential source of atmospheric AHs.Herein,field observations in a eutrophic lake were combined with laboratory incubation experiments to investigate the biogenic AH emission.Field work showed that the water-air fluxes of AHs measured at sites with high cyanobacteria abundance could reach an order of magnitude greater than those at sites with low cyanobacteria abundance,suggesting that cyanobacteria could be the important contributor to measured AHs.Laboratory incubation experiments further confirmed the AH emission of cyanobacteria and revealed that the emission could change significantly over the lifespan of cyanobacteria and varied to their growing conditions.By combining field observations and laboratory incubation experiments,it has been suggested that the emission of different AH species from cyanobacteria could be modulated by variable biogeochemical mechanisms and that the biochemical process of toluene could be different from that of other AHs.This study investigates AH emissions from inland aquatic ecosystem and suggests that biogenic emission could be a potential source of atmospheric AHs.展开更多
Aqueous-phase reactions between carbonyls and reduced nitrogen compounds play a considerable role in the formation of secondary organic aerosols and brown carbon in the atmosphere.However,the reported reaction rate co...Aqueous-phase reactions between carbonyls and reduced nitrogen compounds play a considerable role in the formation of secondary organic aerosols and brown carbon in the atmosphere.However,the reported reaction rate constants for these reactions have largely been limited to bulk aqueous-phase simulations,which may not accurately represent the real state of atmospheric cloud droplets.We employed an integration of optical tweezers and Raman spectroscopy to manipulate and analyze simulated cloud droplets(size range8000-10,000 nm),comprising a mixture of glyoxal and ammonium sulfate.This approach enabled us to delve into the intricate realm of their reaction kinetics at individual droplet level mimicking cloud droplets.Raman spectroscopy provided high temporal resolution(20 s)measurements of the changes in the amount of nitrogen-containing organics(or NOCs as represented by the C-N bond)within the droplets.The results indicate that the reaction follows first-order kinetics throughout the monitoring over 80-400 min.The average reaction rate constant for the formation of NOCs within the single droplet was determined to be(6.77±0.98)×10^(-5)s^(-1),up to three orders of magnitude higher than those through the bulk aqueous-phase simulations,especially at lower p H levels.Additionally,the reaction rate constant in single droplet increases with increasing p H,consistent with the trend previously reported for the bulk aqueous-phase simulations.The results highlight the difference of the reaction rate constant between bulk aqueous-phase and droplets,which would improve our understanding on the formation and impacts of secondary organic aerosols and brown carbon in atmospheric aqueous phase.展开更多
Alcohol industry residues(AIRs)are protein-rich lignocellulosic biowastes from a major industry,having the dual traits of renewable biomass and organic waste.They mainly consist of Brewer's spent grains(BSG)and Ba...Alcohol industry residues(AIRs)are protein-rich lignocellulosic biowastes from a major industry,having the dual traits of renewable biomass and organic waste.They mainly consist of Brewer's spent grains(BSG)and Baijiu distiller's grains(BDG),with annual production totaling tens of millions of tons.Recycling these residues effectively is crucial for the environment,society,and industry.Given their unique characteristic of concentrated carbon and nitrogen sources,valorizing AIRs into biocarbon products through thermochemistry is the most sustainable method for waste management,resource recycling,and green ecology.In this review,the preparation and properties of AIRs-derived biocarbon products are systematically discussed.Recent advancements in the green thermochemical valorization of AIRs into biocarbon products for various applications like thermal utilization,environmental remediation,and energy storage are comprehensively reviewed.It is suggested that hydrothermal carbonization,coupled with necessary chemical functionalization(e.g.,using metal oxides and oxysalts),would be a preferable strategy for producing desired functionalized biocarbon for use as carbon adsorbents(for wastewater treatment)and carbon fertilizers(for soil conservation).The yield and quality of functionalized biocarbon can be ensured through the directional regulation of the migration of essential elements like carbon and nitrogen.The co-generation of nitrogen-doped biochar and nitrogen-enriched liquid fertilizer using innovative hydrothermal strategies is identified as a potential research avenue to achieve the full and cascading utilization of AIRs.This review aims to provide an overview and insights into thermochemically valorizing AIRs alongside other light industrial residues for relevant researchers.展开更多
The exposure to plastic debris and associated pollutants for wildlife is of urgent concern,but little attention has been paid on the transfer of plastic additives from plastic debris to organisms.In the present study,...The exposure to plastic debris and associated pollutants for wildlife is of urgent concern,but little attention has been paid on the transfer of plastic additives from plastic debris to organisms.In the present study,the leaching of incorporated flame retardants (FRs),including polybrominated diphenyl ethers (PBDEs),alternative brominated FRs (AFRs),and phosphate flame retardants (PFRs),from different sizes of recycled acrylonitrile-butadiene-styrene (ABS) polymer were investigated in avian digestive fluids.The impact of co-ingested sediment on the leaching of additive-derived FRs in digestive fluids was also explored.In the recycled ABS,BDE 209 (715 μg/g) and 1,2-bis(2,4,6-tribromophenoxy) ethane (BTBPE,1766 μg/g) had the highest concentrations among all target FRs.The leaching proportions of FRs were higher in finer sizes of ABS.The leaching proportions of FRs from recycled ABS increased with elevated logKow of FRs.In the tests with coexisted ABS and sediment,hexato deca-BDEs,BTBPE,and decabromodiphenyl ethane (DBDPE) migrated from ABS to sediment,which resulted in the less bioaccessible fractions of these FRs in gut fluids.More lipophilic chemicals tended to be adsorbed by sediment from ABS.The results suggest the migration of additive-derived FRs from plastics to other indigestible materials in digestive fluids.The findings in this study provide insights into the transfer of additive-derived FRs from plastics to birds,and indicate the significant contribution of FR-incorporated plastics to bioaccumulation of highly lipophilic FRs.展开更多
Vertical profiles of isoprene and monoterpenes were measured by a proton transfer reactiontime of flight-mass spectrometry(PTR-ToF-MS) at heights of 3,15,32,64,and 102 m above the ground on the Institute of Atmospheri...Vertical profiles of isoprene and monoterpenes were measured by a proton transfer reactiontime of flight-mass spectrometry(PTR-ToF-MS) at heights of 3,15,32,64,and 102 m above the ground on the Institute of Atmospheric Physics(IAP) tower in central Beijing during the winter of 2016 and the summer of 2017.Isoprene mixing ratios were larger in summer due to much stronger local emissions whereas monoterpenes were lower in summer due largely to their consumption by much higher levels of ozone.Isoprene mixing ratios were the highest at the 32 m in summer(1.64±0.66 ppbV) and at 15 m in winter(1.41±0.64 ppbV) with decreasing concentrations to the ground and to the 102 m,indicating emission from the tree canopy of the surrounding parks.Monoterpene mixing ratios were the highest at the 3 m height in both the winter(0.71±0.42 ppbV) and summer(0.16±0.10 ppbV) with a gradual decreasing trend to 102 m,indicting an emission from near the ground level.The lowest isoprene and monoterpene mixing ratios all occurred at 102 m,which were 0.71±0.42 ppbV(winter) and 1.35±0.51 ppbV(summer) for isoprene,and 0.42±0.22 ppbV(winter) and0.07±0.06 ppbV(summer) for monoterpenes.Isoprene in the summer and monoterpenes in the winter,as observed at the five heights,showed significant mutual correlations.In the winter monoterpenes were positively correlated with combustion tracers CO and acetonitrile at 3 m,suggesting possible anthropogenic sources.展开更多
This study investigates seasonal variations of mass absorption efficiency of elemental carbon(MAE_(EC))and possible influencing factors in urban Guangzhou of South China.Mass concentrations of elemental carbon(EC)and ...This study investigates seasonal variations of mass absorption efficiency of elemental carbon(MAE_(EC))and possible influencing factors in urban Guangzhou of South China.Mass concentrations of elemental carbon(EC)and organic carbon(OC)in PM_(2.5) and aerosol absorption coefficient(b_(ap))at multi-wavelengths were simultaneously measured in four seasons of 2018-2019 at hourly resolution by a semi-continuous carbon analyzer and an aethalometer.Seasonal average mass concentrations of EC were in the range of 1.36-1.70μgC/m^(3) with a lower value in summer than in the other seasons,while those of OC were in the range of 4.70–6.49μgC/m^(3) with the lowest value in summer and the highest in autumn.Vehicle exhaust from local traffic was identified to be the predominant source of carbonaceous aerosols.The average aerosol absorption Angstrom exponents(AAE)were lower than 1.2 in four seasons,indicating EC and b_(ap) were closely related with vehicle exhaust.Seasonal MAE EC at 550 nm was 11.0,8.5,10.4 and 11.3 m^(2)/g in spring,summer,autumn,and winter,respectively.High MAE EC was related with the high mass ratio of non-carbonaceous aerosols to EC and high ambient relative humidity.展开更多
Laboratory studies of HO2 uptake coefficients,γ(HO2),were conducted at room temperature using an aerosol flow tube coupled with a laser induced fluorescence(LIF) system.The measurement was conducted with atmospherica...Laboratory studies of HO2 uptake coefficients,γ(HO2),were conducted at room temperature using an aerosol flow tube coupled with a laser induced fluorescence(LIF) system.The measurement was conducted with atmospherically relevant HO2 concentrations(~1×10^9 molecule/cm^3) at 51% RH.The measured γ(HO2) onto aqueous(NH4)2 SO4 aerosol was 0.001±0.0007,which was consistent with the relatively low first-order loss rate of HO2 onto aqueous(NH4)2 SO4 aerosol.Theγ(HO2) was elevated with increase of Cu(Ⅱ) concentrations in aqueous(NH4)2 SO4 aerosol.The threshold of Cu(Ⅱ) concentration was10^-3 mol/L for the dramatic increase of γ(HO2).It was found that γ(HO2) reached 0.1 when Cu(Ⅱ)concentration in aerosol was larger than 10^-3 mol/L,suggesting that γ(HO2) is very sensitive to concentration of transition metal ions in aerosol.展开更多
The environmental stability of infectious viruses in the laboratory setting is crucial to the transmission potential of human respiratory viruses.Different experimental techniques or conditions used in studies over th...The environmental stability of infectious viruses in the laboratory setting is crucial to the transmission potential of human respiratory viruses.Different experimental techniques or conditions used in studies over the past decades have led to diverse understandings and predictions for the stability of viral infectivity in the atmospheric environment.In this paper,we review the current knowledge on the effect of simulated atmospheric conditions on the infectivity of respiratory viruses,mainly focusing on influenza viruses and coronaviruses,including severe acute respiratory syndrome coronavirus 2 and Middle East respiratory syndrome coronavirus.First,we summarize the impact of the experimental conditions on viral stability;these involve the methods of viral aerosol generation,storage during aging and collection,the virus types and strains,the suspension matrixes,the initial inoculum volumes and concentrations,and the drying process.Second,we summarize and discuss the detection methods of viral infectivity and their disadvantages.Finally,we integrate the results from the reviewed studies to obtain an overall understanding of the effects of atmospheric environmental conditions on the decay of infectious viruses,especially aerosolized viruses.Overall,this review highlights the knowledge gaps in predicting the ability of viruses to maintain infectivity during airborne transmission.展开更多
Organic compounds are important contributors to the optical properties and health effects of combustion-derived particles.However,the connection between optical properties and toxicity of combustion particles remains ...Organic compounds are important contributors to the optical properties and health effects of combustion-derived particles.However,the connection between optical properties and toxicity of combustion particles remains a matter of little concern.In this study,combustion particles were collected from 11 primary sources,including biomass burning,coal combustion,and vehicle exhaust.The extractable organic matter(EOM)in bituminous coal combustion particles shows the highest light-absorption,fluorescence properties,and toxicity among samples.Parallel factor(PARAFAC)analysis combined excitation−emission matrix(EEM)spectroscopy resolved 4 types of basic chromophore components in EOM.Fourier transform ion cyclotron resonance mass spectrometry(FT-ICR MS)analysis further resolved∼800 molecules,predominantly aromatics(84%±4.6%),which showed positive correlations with the light-absorption,fluorescence properties and toxicity of EOM(p<0.05).Aromatics are inferred to be the intrinsic link between the optical properties and toxicity of EOM in combustion particles.Additionally,the benzene poly(carboxylic acid)s(BPCAs)method,which could identify and quantify fused benzene rings in EOM,further indicates the high condensation degree of aromatics is closely correlated with the lightabsorption,fluorescence properties of EOM.However,the toxicity of EOM may depend on the bay or fjord region of aromatics.These findings provide valuable insights into the light-absorption,fluorescence properties and toxicity of EOM in combustion particles.展开更多
基金supported by the National Natural Science Foundation of China(No.42192514)Guangdong Major Project of Basic and Applied Basic Research(No.2023B0303000007)and Guangdong Foundation for Program of Science and Technology Research(No.2023B1212060049)。
文摘Dissolved organic matter(DOM)is ubiquitous in the environment and plays an important role in global ecosystems.However,our understanding of the evolution and molecular diversity of DOM from different biomass materials and biochar is not enough.Herein,we investigated the changes in DOM from seven biomass and biochar samples over a bio-incubation of 28 days,and explored their contents,and optical,chemical,and molecular characteristics.The results indicated that dissolved organic carbon(DOC)from different sources all exhibited a gradually decreasing trends during the incubation,while the absorbance and aromaticity gradually increased.Biomass DOM was characterized by higher DOC concentrations and a higher degradation rate,whereas biochar DOM had high aromaticity and little variability.Parallel factor analysis results showed that the protein-like fluorescent groups were as only detected in biomass DOM,while the dominant humic-like components were identified in biochar DOM.Additionally,the molecular composition of DOM from different sources was different,and biomass DOM contained more carbohydrate-like and saturated compounds.More sulfur-containing compounds were detected in Ceratophyllum demersum(CD)DOM,which may indicate that the leaching of CD litter was an important source of sulfur-containing species in aquatic environments.Furthermore,biochar DOM had greater aromaticity and a higher degree of oxidation than the corresponding biomass DOM.This study provided a detailed understanding of the molecular diversity of DOM by considering its various sources,and the results are helpful for further understanding their chemical properties and structures.
基金supported by the National Key Research and Development Program of China(No.2022YFC3701103)the National Natural Science Foundation of China(No.42222705)+1 种基金the Youth Innovation Promotion Association CAS(No.2021354)Guangdong Foundation for Program of Science and Technology Research(No.2023B1212060049).
文摘Nitrogen-containing organic compounds(NOCs)may potentially contribute to aqueous secondary organic aerosols,yet the different formation of NOCs in aerosol particles and cloud droplets remains unclear.With the in-situ measurements performed at a mountain site(1690 m a.s.l.)in southern China,we investigated the formation of NOCs in the cloud droplets and the cloud-free particles,based on their mixing state information of NOCscontaining particles by single particle mass spectrometry.The relative abundance of NOCs in the cloud-free particles was significantly higher than those in cloud residual(cloud RES)particles.NOCs were highly correlated with carbonyl compounds(including glyoxalate and methylglyoxal)in the cloud-free particles,however,limited correlation was observed for cloud RES particles.Analysis of their mixing state and temporal variations highlights that NOCs was mainly formed from the carbonyl compounds and ammonium in the cloud-free particles,rather than in the cloud RES particles.The results support that the formation of NOCs from carbonyl compounds is facilitated in concentrated solutions in wet aerosols,rather than cloud droplets.In addition,we have identified the transport of biomass burning particles that facilitate the formation of NOCs,and that the observed NOCs is most likely contributed to the light absorption.These findings have implications for the evaluation of NOCs formation and their contribution to light absorption.
基金supported by the National Natural Science Foundation of China(Nos.42022023 and 41961144029)the Chinese Academy of Sciences(Nos.XDA23010303,XDPB1901,XDA23020301 and QYZDJ-SSW-DQC032)+2 种基金the Department of Science and Technology of Guangdong(Nos.2020B1111360001and 2020B1212060053)the Youth Innovation Promotion Association of the Chinese Academy of Sciences(No.2017406)the Hong Kong Research Grants Council(No.T24-504/17-N)
文摘The impact of reducing industrial emissions of volatile organic compounds(VOCs)on ozone(O_(3))pollution is of wide concern particularly in highly industrialized megacities.In this study,O_(3),nitrogen oxides(NOx)and VOCs were measured at an urban site in the Pearl River Delta region during the 2018 Chinese National Day Holidays and two after-holiday periods(one with ozone pollution and another without).O_(3)pollution occurred throughout the 7-day holidays even industrial emissions of VOCswere passively reduced due to temporary factory shutdowns,and the toluene to benzene ratios dropped from∼10 during non-holidays to∼5 during the holidays.Box model(AtChem2-MCM)simulations with the input of observation data revealed that O_(3)formation was all VOC-limited,and alkenes had the highest relative incremental reactivity(RIR)during the holiday and non-holiday O_(3)episodes while aromatics had the highest RIR during the non-pollution period.Box model also demonstrated that even aromatics decreased proportionally to levels with near-zero contributions of industrial aromatic solvents,O_(3)concentrations would only decrease by less than 20%during the holiday and non-holiday O_(3)episodes and ozone pollution in the periods could not be eliminated.The results imply that controlling emissions of industrial aromatic solvents might be not enough to eliminate O_(3)pollution in the region,and more attention should be paid to anthropogenic reactive alkenes.Isoprene and formaldehyde were among the top 3 species by RIRs in all the three pollution and non-pollution periods,suggesting substantial contribution to O_(3)formation from biogenic VOCs.
基金funded by Natural Science Foundation of China (Project Nos. 41530641/41571130031)Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDB05010200)+1 种基金Chinese Academy of Sciences (Grant No. QYZDJ-SSW-DQC032)Guangdong Provincial Scientific Planning project (Project No. 2016B050502005)
文摘Chemical speciation of fine particles or PM2.5 collected on filters is still a cosily and time- consuming task. In this study, filter-based PM2.5 samples were collected during November-December 2013 at four sites in Guangzhou, and the major components were fast screened （~ 7 rain per filter sample） by Attenuated Total Reflectance （ATR）-Fourier Transform Infrared Spectroscopic （FTIR） in comparison with that measured by Organic carbon/Element carbon （OC/ EC） analyzer and Ion Chromatography （IC）. The concentrations of nitrate, ammonium, sulfate, primary organic carbon （POC） and secondary organic carbon （SOC） measured by OC/EC and IC analyzers were better correlated with their infrared absorption peak heights at 1320 cm 1 for nitrate, 1435, 3045 and 3215 cm^-1 for ammonium, 615 cm^-1 for sulfate, 690, 760 and 890 cm^-1 for POC and 1640 and 1660 cm^-1 for SOC respectively, during polluted days （PM2.5 〉 75 μg/m^3） than during clean days （PM2.5〈 75 μg/m^3）. With the evolution of a haze episode during our field campaign, the concentrations of the major PM2.5 components displayed consistent variations with their infrared absorption peak heights, suggesting ATR-FTIR could be a fast and useful technique to characterize filter-based PM2.5 compositions particularly during pollution events although cautions should be taken when PM2.5 levels are low. Notably, elevated PM2.5 mass concentrations occurred with enhanced ratios of [NO^-3][SO^2-4] and [NH^＋4]/[SO^2-4], implying that nitrogenous components play vital roles in the PM2.5 pollution events in the study region.
基金the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA23020301)the National Natural Science Foundation of China(Nos.51778596,41977184,and 41941011)+5 种基金the Key Research and Development Project of Anhui Province(202104i07020002)the Anhui Science and Technology Major Project(No.18030801111)the Major Projects of High Resolution Earth Observation Systems of National Science and Technology(05-Y30B01-9001-19/20-3)the Youth Innovation Promotion Association of CAS(2021443)the Young Talent Project of the Center for Excellence in Regional Atmospheric Environment,CAS(CERAE202004)the Fundamental Research Funds for the Central Universities(No.JUSRP12042)。
文摘Formaldehyde(HCHO)and glyoxal(CHOCHO)are important oxidization intermediates of most volatile organic compounds(VOCs),but their vertical evolution in urban areas is not well understood.Vertical profiles of HCHO,CHOCHO,and nitrogen dioxide(NO_(2))were retrieved from ground-based Multi-Axis Differential Optical Absorption Spectroscopy(MAXDOAS)observations in Hefei,China.HCHO and CHOCHO vertical profiles prefer to occur at higher altitudes compared to NO_(2),which might be caused by the photochemistry-oxidation of longer-lived VOCs at higher altitudes.Monthly means of HCHO concentrations were higher in summer,while enhanced amounts of NO_(2)were mainly observed in winter.CHOCHO exhibited a hump-like seasonal variation,with higher monthly-averaged values not only occurred in warm months(July-August)but also in cold months(November-December).Peak values mainly occurred during noon for HCHO but emerged in the morning for CHOCHO and NO_(2),suggesting that HCHO is stronger link to photochemistry than CHOCHO.We further use the glyoxal to formaldehyde ratio(GFR)to investigate the VOC sources at different altitudes.The lowest GFR value is almost found in the altitude from 0.2 to 0.4 km,and then rises rapidly as the altitude increases.The GFR results indicate that the largest contributor of the precursor VOC is biogenic VOCs at lower altitudes,while at higher altitudes is anthropogenic VOCs.Our findings provide a lot more insight into VOC sources at vertical direction,but more verification is recommended to be done in the future.
基金funded by Ministry of Science and Technology of China(No.2018YFC0213901)National Natural Science Foundation of China(Nos.91744204 and 41675120)+4 种基金Guangdong Foundation for Program of Science and Technology Research(Nos.2017B030314057 and 2019B121205006)the Science and Technology Development Fund,Macao SAR(No.016/2017/A1)the Multi-Year Research grant(No.MYRG2018-00006-FST)from the University of MacaoOpen Grant from State Key Lab of Organic Geochemistry Chinese Academy of Sciencesthe CAS Pioneer Hundred Talents program for providing a starting grant
文摘Mineral dust,soil,and sea salt aerosols are among the most abundant primary inorganic aerosols in the atmosphere,and their hygroscopicity affects the hydrological cycle and global climate.We investigated the hygroscopic behaviors of six Na-and K-containing salts commonly found in those primary organic aerosols.Their hygroscopic growths as a function of relative humidity(RH) agree well with thermodynamic model prediction.Temperature dependence of deliquescence RH(DRH) values for five of those salts was also investigated,which are comparable to those in literature within 1%-2% RH,most showing negative dependence on temperature.Hygroscopic growth curves of real-world soil and sea salt samples were also measured.The hygroscopic growths of two more-hydroscopic saline soil samples and of sea salt can be predicted by the thermodynamic model based on the measured water-soluble ionic composition.The substantial amounts of water-soluble ions,including Na+and K+,in saline soil samples imply that even nascent saline soil samples are quite hygroscopic at high-RH(>80%) conditions.For three less-hygroscopic dust samples,however,measurements showed higher water uptake ability than that predicted by the thermodynamic model.The small amount of water taken up by less-hygroscopic dust samples suggests that dust particles might contain thin layers of water even to very low RH.The results of this study provide a comprehensive characterization of the hygroscopicity of Na-and K-containing salts as related to their roles in the hygroscopic behaviors of saline mineral dusts and sea salt aerosols.
基金supported by the National Natural Science Foundation of China(No.42022050)Guangdong Foundation for Program of Science and Technology Research(Nos.2019B121205006 and 2020B1212060053)+1 种基金the Guangdong Science and Technology Department(No.2017GC010501)CAS Pioneer Hundred Talents program.
文摘Heterogeneous reaction of NO_(2) with mineral dust aerosol may play important roles in troposphere chemistry,and has been investigated by a number of laboratory studies.However,the influence of mineralogy on this reaction has not been well understood,and its impact on aerosol hygroscopicity is not yet clear.This work investigated heterogeneous reactions of NO_(2)(∼10 ppmv)with K-feldspar,illite,kaolinite,montmorillonite and Arizona Test Dust(ATD)at room temperature as a function of relative humidity(<1%to 80%)and reaction time(up to 24 hr).Heterogeneous reactivity towards NO_(2) was low for illite,kaolinite,montmorillonite and ATD,and uptake coefficients of NO_(2),γ(NO_(2)),were determined to be around or smaller than 1×10^(−8);K-feldspar exhibited higher reactivity towards NO_(2),and CaCO_(3) is most reactive among the nine mineral dust samples considered in this and previous work.After heterogeneous reaction with NO_(2) for 24 hr,increase in hygroscopicity was nearly insignificant for illite,kaolinite and montmorillonite,and small but significant for K-feldspar;in addition,large increase in hygroscopicity was observed for ATD,although the increase in hygroscopicity was still smaller than CaCO_(3).
基金supported by the National Natural Science Foundation of China(No.42022050)the Guangdong Basic and Applied Basic Research Fund Committee(No.2020B1515130003)+3 种基金the Guangdong Foundation for Program of Science and Technology Research(Nos.2019B121205006 and 2020B1212060053)the Guangdong Science and Technology Department(No.2017GC010501)the CAS Pioneer Hundred Talents program.We would like to thank Ryan Sullivan(Carnegie Mellon University,USA)the Nadine Borduas-Dedekind(University of British Columbia,Canada)for sharing their original data.
文摘Mineral dust is an important type of ice nucleating particles in the troposphere;however,the effects of heterogeneous reactions on ice nucleation(IN)activities of mineral dust remain to be elucidated.A droplet-freezing apparatus(Guangzhou Institute of Geochemistry Ice Nucleation Apparatus,GIGINA)was developed in thiswork to measure IN activities of atmospheric particles in the immersion freezingmode,and its performancewas validated by a series of experimental characterizations.This apparatus was then employed to measure IN activities of feldspar and Arizona Test Dust(ATD)particles before and after heterogeneous reaction with NO_(2)(10±0.5 ppmv)at 40%relative humidity.The surface coverage of nitrate,θ(NO_(3)^(−)),increased to 3.1±0.2 for feldspar after reaction with NO_(2) for 6 hr,and meanwhile the active site density per unit surface area(ns)at-20℃ was reduced from 92±5 to<1.0 cm^(−2) by about two orders of magnitude;however,no changes in nitrate content or IN activities were observed for further increase in reaction time(up to 24 hr).Both nitrate content and IN activities changed continuously with reaction time(up to 24 hr)for ATD particles;after reaction with NO_(2) for 24 hr,θ(NO_(3)^(−))increased to 1.4±0.1 and ns at-20℃ was reduced from 20±4 to 9.7±1.9 cm^(−2) by a factor of∼2.Our work suggests that heterogeneous reaction with NO_(2),an abundant reactive nitrogen species in the troposphere,may significantly reduce IN activities of mineral dust in the immersion freezing mode.
基金supported by Guangdong Natural Science Funds for Distinguished Young Scholar (No. S2013050014122)Guangzhou Institute of Geochemistry, Chinese Academy of Sciences (No. 2012-03) (135 project)No. IS-2062 from GIGGAS
文摘n-Hexane is widely used in industrial production as an organic solvent. As an industrial exhaust gas, the contribution of n-hexane to air pollution and damage to human health are attracting increasing attention. In the present study, aqueous solutions of two fluorocarbon surfactants（FSN100 and FSO100） were investigated for their properties of solubilization and dynamic absorption of n-hexane, as well as their capacity for regeneration and n-hexane recovery by thermal distillation. The results show that the two fluorocarbon surfactants enhance dissolution and absorption of n-hexane, and their effectiveness is closely related to their concentrations in solution. For low concentration solutions（0.01%–0.30%）, the partition coefficient decreases dramatically and the saturation capacity increases significantly with increasing concentration, but the changes for both are more modest when the concentration is over 0.30%. The FSO100 solution presents a smaller partition coefficient and a greater saturation capacity than the FSN100 solution at the same concentration,indicating a stronger solubilization for n-hexane. Thermal distillation is a feasible method to recover n-hexane from these absorption solutions, and to regenerate them. With 90 sec heating at 80–85°C, the recovery of n-hexane ranges between 81% and 85%, and the regenerated absorption solution maintains its original performance during reuse. This study provides basic information on two fluorocarbon surfactants for application in the treatment of industrial n-hexane waste gases.
基金supported by the National Natural Science Foundation of China (Nos.42022050 and 42277088)the Guangdong Basic and Applied Basic Research Fund Committee (Nos.2021A1515011248 and 2023A1515012010)the Guangdong Foundation for the Program of Science and Technology Research (No.2020B1212060053).
文摘Thermodynamic modeling is still themostwidely usedmethod to characterize aerosol acidity,a critical physicochemical property of atmospheric aerosols.However,it remains unclear whether gas-aerosol partitioning should be incorporated when thermodynamicmodels are employed to estimate the acidity of coarse particles.In this work,field measurements were conducted at a coastal city in northern China across three seasons,and covered wide ranges of temperature,relative humidity and NH_(3) concentrations.We examined the performance of different modes of ISORROPIA-II(a widely used aerosol thermodynamic model)in estimating aerosol acidity of coarse and fine particles.The M0 mode,which incorporates gas-phase data and runs the model in the forward mode,provided reasonable estimation of aerosol acidity for coarse and fine particles.Compared to M0,the M1 mode,which runs the model in the forward mode but does not include gas-phase data,may capture the general trend of aerosol acidity but underestimates pH for both coarse and fine particles;M2,which runs the model in the reverse mode,results in large errors in estimated aerosol pH for both coarse and fine particles and should not be used for aerosol acidity calculations.However,M1 significantly underestimates liquid water contents for both fine and coarse particles,while M2 provides reliable estimation of liquid water contents.In summary,our work highlights the importance of incorporating gas-aerosol partitioning when estimating coarse particle acidity,and thus may help improve our understanding of acidity of coarse particles.
基金supported by the National Natural Science Foundation of China(No.91844000)China Postdoctoral Science Foundation(No.2020M670048).
文摘The acidity of atmospheric aerosols influences fundamental physicochemical processes that affect climate and human health.We recently developed a novel and facilewater-probebased method for directly measuring of the pH for micrometer-size droplets,providing a promising technique to better understand aerosol acidity in the atmosphere.The complex chemical composition of fine particles in the ambient air,however,poses certain challenges to using a water-probe for pH measurement,including interference from interactions between compositions and the influence of similar compositions on water structure.To explore the universality of our method,it was employed to measure the pH of ammonium,nitrate,carbonate,sulfate,and chloride particles.The pH of particles covering a broad range(0–14)were accurately determined,thereby demonstrating that our method can be generally applied,even to alkaline particles.Furthermore,a standard spectral library was developed by integrating the standard spectra of common hydrated ions extracted through the waterprobe.The library can be employed to identify particle composition and overcome the spectral overlap problem resulting from similar effects.Using the spectral library,all ions were identified and their concentrations were determined,in turn allowing successful pH measurement of multicomponent(ammonium-sulfate-nitrate-chloride)particles.Insights into the synergistic effect of Cl^(–),NO_(3)^(–),and NH_(4)^(+)depletion obtained with our approach revealed the interplay between pH and volatile partitioning.Given the ubiquity of component partitioning and pH variation in particles,the water probemay provide a new perspective on the underlying mechanisms of aerosol aging and aerosol–cloud interaction.
基金supported by the National Natural Science Foundation of China(Nos.42207128 and 41273095)the Natural Science Foundation of Anhui Province(No.2008085MD111)the Key Research Projects of Natural Science in Colleges and Universities of Anhui Province(No.KJ2021A0091).
文摘As important precursors of ozone(O_(3))and secondary organic aerosol(SOA),reactive aromatic hydrocarbons(AHs)have typically been classified as anthropogenic air pollutants.However,biogenic emission can also be a potential source of atmospheric AHs.Herein,field observations in a eutrophic lake were combined with laboratory incubation experiments to investigate the biogenic AH emission.Field work showed that the water-air fluxes of AHs measured at sites with high cyanobacteria abundance could reach an order of magnitude greater than those at sites with low cyanobacteria abundance,suggesting that cyanobacteria could be the important contributor to measured AHs.Laboratory incubation experiments further confirmed the AH emission of cyanobacteria and revealed that the emission could change significantly over the lifespan of cyanobacteria and varied to their growing conditions.By combining field observations and laboratory incubation experiments,it has been suggested that the emission of different AH species from cyanobacteria could be modulated by variable biogeochemical mechanisms and that the biochemical process of toluene could be different from that of other AHs.This study investigates AH emissions from inland aquatic ecosystem and suggests that biogenic emission could be a potential source of atmospheric AHs.
基金supported by the National Natural Science Foundation of China(Nos.42222705,42377097,and 22361162668)the National Key Research and Development Program of China(No.2022YFC3701101)+1 种基金the Youth Innovation Promotion Association CAS(No.2021354)Guangdong Foundation for Program of Science and Technology Research(No.2023B1212060049)。
文摘Aqueous-phase reactions between carbonyls and reduced nitrogen compounds play a considerable role in the formation of secondary organic aerosols and brown carbon in the atmosphere.However,the reported reaction rate constants for these reactions have largely been limited to bulk aqueous-phase simulations,which may not accurately represent the real state of atmospheric cloud droplets.We employed an integration of optical tweezers and Raman spectroscopy to manipulate and analyze simulated cloud droplets(size range8000-10,000 nm),comprising a mixture of glyoxal and ammonium sulfate.This approach enabled us to delve into the intricate realm of their reaction kinetics at individual droplet level mimicking cloud droplets.Raman spectroscopy provided high temporal resolution(20 s)measurements of the changes in the amount of nitrogen-containing organics(or NOCs as represented by the C-N bond)within the droplets.The results indicate that the reaction follows first-order kinetics throughout the monitoring over 80-400 min.The average reaction rate constant for the formation of NOCs within the single droplet was determined to be(6.77±0.98)×10^(-5)s^(-1),up to three orders of magnitude higher than those through the bulk aqueous-phase simulations,especially at lower p H levels.Additionally,the reaction rate constant in single droplet increases with increasing p H,consistent with the trend previously reported for the bulk aqueous-phase simulations.The results highlight the difference of the reaction rate constant between bulk aqueous-phase and droplets,which would improve our understanding on the formation and impacts of secondary organic aerosols and brown carbon in atmospheric aqueous phase.
基金supported by the National Natural Science Foundation of China(No.51906247)the Hunan Provincial Natural Science Foundation of China(Grant No.2023JJ30691)the Guangdong Foundation for Program of Science and Technology Research(Grant No.2023B1212060049).
文摘Alcohol industry residues(AIRs)are protein-rich lignocellulosic biowastes from a major industry,having the dual traits of renewable biomass and organic waste.They mainly consist of Brewer's spent grains(BSG)and Baijiu distiller's grains(BDG),with annual production totaling tens of millions of tons.Recycling these residues effectively is crucial for the environment,society,and industry.Given their unique characteristic of concentrated carbon and nitrogen sources,valorizing AIRs into biocarbon products through thermochemistry is the most sustainable method for waste management,resource recycling,and green ecology.In this review,the preparation and properties of AIRs-derived biocarbon products are systematically discussed.Recent advancements in the green thermochemical valorization of AIRs into biocarbon products for various applications like thermal utilization,environmental remediation,and energy storage are comprehensively reviewed.It is suggested that hydrothermal carbonization,coupled with necessary chemical functionalization(e.g.,using metal oxides and oxysalts),would be a preferable strategy for producing desired functionalized biocarbon for use as carbon adsorbents(for wastewater treatment)and carbon fertilizers(for soil conservation).The yield and quality of functionalized biocarbon can be ensured through the directional regulation of the migration of essential elements like carbon and nitrogen.The co-generation of nitrogen-doped biochar and nitrogen-enriched liquid fertilizer using innovative hydrothermal strategies is identified as a potential research avenue to achieve the full and cascading utilization of AIRs.This review aims to provide an overview and insights into thermochemically valorizing AIRs alongside other light industrial residues for relevant researchers.
基金supported by the National Natural Science Foundation of China(Nos.41603085 and 41877361)the Natural Science Foundation of Guangdong Province(No.2016A030310440)+2 种基金the Pearl River S&T Nova Program of Guangzhou(No.201806010185)the Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program(No.2017BT01Z134)the Key Research Program of Frontier Sciences,the Chinese Academy of Science(No.QYZDJ-SSW-DQC018)
文摘The exposure to plastic debris and associated pollutants for wildlife is of urgent concern,but little attention has been paid on the transfer of plastic additives from plastic debris to organisms.In the present study,the leaching of incorporated flame retardants (FRs),including polybrominated diphenyl ethers (PBDEs),alternative brominated FRs (AFRs),and phosphate flame retardants (PFRs),from different sizes of recycled acrylonitrile-butadiene-styrene (ABS) polymer were investigated in avian digestive fluids.The impact of co-ingested sediment on the leaching of additive-derived FRs in digestive fluids was also explored.In the recycled ABS,BDE 209 (715 μg/g) and 1,2-bis(2,4,6-tribromophenoxy) ethane (BTBPE,1766 μg/g) had the highest concentrations among all target FRs.The leaching proportions of FRs were higher in finer sizes of ABS.The leaching proportions of FRs from recycled ABS increased with elevated logKow of FRs.In the tests with coexisted ABS and sediment,hexato deca-BDEs,BTBPE,and decabromodiphenyl ethane (DBDPE) migrated from ABS to sediment,which resulted in the less bioaccessible fractions of these FRs in gut fluids.More lipophilic chemicals tended to be adsorbed by sediment from ABS.The results suggest the migration of additive-derived FRs from plastics to other indigestible materials in digestive fluids.The findings in this study provide insights into the transfer of additive-derived FRs from plastics to birds,and indicate the significant contribution of FR-incorporated plastics to bioaccumulation of highly lipophilic FRs.
基金supported by the National Natural Science Foundation of China(Nos.41571130031,41673116,41703112,41603070)the Natural Environment Research Council(Nos.NE/N006992/1 and NE/N006976/1)+3 种基金Theme-based Research Scheme(No.T24-504/17-N)Youth Innovation Promotion Association of the Chinese Academy of Sciences(No.2017406)Guangdong Foundation for Program of Science and Technology Research(No.2017B030314057)financial support from Natural Environment Research Council(No.NE/N007190/1)
文摘Vertical profiles of isoprene and monoterpenes were measured by a proton transfer reactiontime of flight-mass spectrometry(PTR-ToF-MS) at heights of 3,15,32,64,and 102 m above the ground on the Institute of Atmospheric Physics(IAP) tower in central Beijing during the winter of 2016 and the summer of 2017.Isoprene mixing ratios were larger in summer due to much stronger local emissions whereas monoterpenes were lower in summer due largely to their consumption by much higher levels of ozone.Isoprene mixing ratios were the highest at the 32 m in summer(1.64±0.66 ppbV) and at 15 m in winter(1.41±0.64 ppbV) with decreasing concentrations to the ground and to the 102 m,indicating emission from the tree canopy of the surrounding parks.Monoterpene mixing ratios were the highest at the 3 m height in both the winter(0.71±0.42 ppbV) and summer(0.16±0.10 ppbV) with a gradual decreasing trend to 102 m,indicting an emission from near the ground level.The lowest isoprene and monoterpene mixing ratios all occurred at 102 m,which were 0.71±0.42 ppbV(winter) and 1.35±0.51 ppbV(summer) for isoprene,and 0.42±0.22 ppbV(winter) and0.07±0.06 ppbV(summer) for monoterpenes.Isoprene in the summer and monoterpenes in the winter,as observed at the five heights,showed significant mutual correlations.In the winter monoterpenes were positively correlated with combustion tracers CO and acetonitrile at 3 m,suggesting possible anthropogenic sources.
基金supported by the National Natural Science Foundation of China(Nos.41775155,41875160 and 41475119).
文摘This study investigates seasonal variations of mass absorption efficiency of elemental carbon(MAE_(EC))and possible influencing factors in urban Guangzhou of South China.Mass concentrations of elemental carbon(EC)and organic carbon(OC)in PM_(2.5) and aerosol absorption coefficient(b_(ap))at multi-wavelengths were simultaneously measured in four seasons of 2018-2019 at hourly resolution by a semi-continuous carbon analyzer and an aethalometer.Seasonal average mass concentrations of EC were in the range of 1.36-1.70μgC/m^(3) with a lower value in summer than in the other seasons,while those of OC were in the range of 4.70–6.49μgC/m^(3) with the lowest value in summer and the highest in autumn.Vehicle exhaust from local traffic was identified to be the predominant source of carbonaceous aerosols.The average aerosol absorption Angstrom exponents(AAE)were lower than 1.2 in four seasons,indicating EC and b_(ap) were closely related with vehicle exhaust.Seasonal MAE EC at 550 nm was 11.0,8.5,10.4 and 11.3 m^(2)/g in spring,summer,autumn,and winter,respectively.High MAE EC was related with the high mass ratio of non-carbonaceous aerosols to EC and high ambient relative humidity.
基金the National Natural Science Foundation of China (Nos.91544225,21522701) for the financial support
文摘Laboratory studies of HO2 uptake coefficients,γ(HO2),were conducted at room temperature using an aerosol flow tube coupled with a laser induced fluorescence(LIF) system.The measurement was conducted with atmospherically relevant HO2 concentrations(~1×10^9 molecule/cm^3) at 51% RH.The measured γ(HO2) onto aqueous(NH4)2 SO4 aerosol was 0.001±0.0007,which was consistent with the relatively low first-order loss rate of HO2 onto aqueous(NH4)2 SO4 aerosol.Theγ(HO2) was elevated with increase of Cu(Ⅱ) concentrations in aqueous(NH4)2 SO4 aerosol.The threshold of Cu(Ⅱ) concentration was10^-3 mol/L for the dramatic increase of γ(HO2).It was found that γ(HO2) reached 0.1 when Cu(Ⅱ)concentration in aerosol was larger than 10^-3 mol/L,suggesting that γ(HO2) is very sensitive to concentration of transition metal ions in aerosol.
基金supported by the National Natural Science Foundation of China(42130611)Guangdong Foundation for Program of Science and Technology Research(2023B1212060049,2019B121205006).
文摘The environmental stability of infectious viruses in the laboratory setting is crucial to the transmission potential of human respiratory viruses.Different experimental techniques or conditions used in studies over the past decades have led to diverse understandings and predictions for the stability of viral infectivity in the atmospheric environment.In this paper,we review the current knowledge on the effect of simulated atmospheric conditions on the infectivity of respiratory viruses,mainly focusing on influenza viruses and coronaviruses,including severe acute respiratory syndrome coronavirus 2 and Middle East respiratory syndrome coronavirus.First,we summarize the impact of the experimental conditions on viral stability;these involve the methods of viral aerosol generation,storage during aging and collection,the virus types and strains,the suspension matrixes,the initial inoculum volumes and concentrations,and the drying process.Second,we summarize and discuss the detection methods of viral infectivity and their disadvantages.Finally,we integrate the results from the reviewed studies to obtain an overall understanding of the effects of atmospheric environmental conditions on the decay of infectious viruses,especially aerosolized viruses.Overall,this review highlights the knowledge gaps in predicting the ability of viruses to maintain infectivity during airborne transmission.
基金supported by the National Natural Science Foundation of China(No.42030715 and 42192511)the Alliance of International Science Organizations(ANSO-CRKP-2021-05)+1 种基金the Basic and Applied Basic Research Foundation of Guangdong Province(2023B0303000007,2023B1515020067 and 2022A1515011271)the Youth Innovation Promotion Association of the Chinese Academy of Sciences(2022359).
文摘Organic compounds are important contributors to the optical properties and health effects of combustion-derived particles.However,the connection between optical properties and toxicity of combustion particles remains a matter of little concern.In this study,combustion particles were collected from 11 primary sources,including biomass burning,coal combustion,and vehicle exhaust.The extractable organic matter(EOM)in bituminous coal combustion particles shows the highest light-absorption,fluorescence properties,and toxicity among samples.Parallel factor(PARAFAC)analysis combined excitation−emission matrix(EEM)spectroscopy resolved 4 types of basic chromophore components in EOM.Fourier transform ion cyclotron resonance mass spectrometry(FT-ICR MS)analysis further resolved∼800 molecules,predominantly aromatics(84%±4.6%),which showed positive correlations with the light-absorption,fluorescence properties and toxicity of EOM(p<0.05).Aromatics are inferred to be the intrinsic link between the optical properties and toxicity of EOM in combustion particles.Additionally,the benzene poly(carboxylic acid)s(BPCAs)method,which could identify and quantify fused benzene rings in EOM,further indicates the high condensation degree of aromatics is closely correlated with the lightabsorption,fluorescence properties of EOM.However,the toxicity of EOM may depend on the bay or fjord region of aromatics.These findings provide valuable insights into the light-absorption,fluorescence properties and toxicity of EOM in combustion particles.
