The petroleum industry is a significant source of anthropogenic volatile organic compounds(VOCs),but up to now,its exact impact on urban VOCs and ozone(O_(3))remains unclear.This study conducted year-long VOC ob-serva...The petroleum industry is a significant source of anthropogenic volatile organic compounds(VOCs),but up to now,its exact impact on urban VOCs and ozone(O_(3))remains unclear.This study conducted year-long VOC ob-servations in Dongying,China,a petroleum industrial region.The VOCs from the petroleum industry(oil and gas volatilization and petrochemical production)were identified by employing the positive matrix factorization model,and their contribution to O_(3) formation was quantitatively evaluated using an observation-based chemical box model.The observed annual average concentration of VOCs was 68.6±63.5 ppbv,with a maximum daily av-erage of 335.3 ppbv.The petroleum industry accounted for 66.5%of total VOCs,contributing 54.9%from oil and gas evaporation and 11.6%from petrochemical production.Model results indicated that VOCs from the petroleum industry contributed to 31%of net O_(3) production,with 21.3%and 34.2%contributions to HO_(2)+NO and RO_(2)+NO pathways,respectively.The larger impact on the RO_(2) pathway is primarily due to the fact that OH+VOCs ac-count for 86.9%of the primary source of RO_(2).This study highlights the critical role of controlling VOCs from the petroleum industry in urban O_(3) pollution,especially those from previously overlooked low-reactivity alkanes.展开更多
Fine particulate matter(PM_(2.5))and ground-level ozone(O_(3))are the primary air pollutants that degrade air quality in urban and regional areas of China.Since the implementation of the“Air Pollution Preven-tion and...Fine particulate matter(PM_(2.5))and ground-level ozone(O_(3))are the primary air pollutants that degrade air quality in urban and regional areas of China.Since the implementation of the“Air Pollution Preven-tion and Control Action Plan”in 2013,ambient concentrations of PM_(2.5)have significantly decreased across China.However,O_(3)levels exhibited an upward trend until 2019 and have since remained elevated,despite the COVID-19 pandemic.Currently,no city in China has achieved the World Health Organization’s guidelines for PM_(2.5)(24-hour mean of 15μg m^(−3)and annual mean of 5μg m^(−3))and O_(3)(8-hour mean of 100μg m^(−3)).Therefore,more rigorous measures are necessary to alleviate PM_(2.5)and O_(3)pollution in China.展开更多
With the development of big data and cloud computing technology,more and more users choose to store data on cloud servers,which brings much convenience to their management and use of data,and also the risk of data lea...With the development of big data and cloud computing technology,more and more users choose to store data on cloud servers,which brings much convenience to their management and use of data,and also the risk of data leakage.A common method to prevent data leakage is to encrypt the data before uploading it,but the traditional encryption method is often not conducive to data sharing and querying.In this paper,a new kind of Attribute-Based Encryption(ABE)scheme,which is called the Sub-String Searchable ABE(SSS-ABE)scheme,is proposed for the sharing and querying of the encrypted data.In the SSS-ABE scheme,the data owner encrypts the data under an access structure,and only the data user who satisfies the access structure can query and decrypt it.The data user can make a substring query on the whole ciphertext without setting keywords in advance.In addition,the outsourcing method is also introduced to reduce the local computation of the decryption process so that the outsourcing SSS-ABE scheme can be applied to IoT devices.展开更多
Observation-based method for O_(3)formation sensitivity research is an important tool to analyze the causes of ground-level O_(3)pollution,which has broad application potentials in determining the O_(3)pollution forma...Observation-based method for O_(3)formation sensitivity research is an important tool to analyze the causes of ground-level O_(3)pollution,which has broad application potentials in determining the O_(3)pollution formation mechanism and developing prevention and control strategies.This paper outlined the development history of research on O_(3)formation sensitivity based on observational methods,described the principle and applicability of the methodology,summarized the relative application results in China and provided recommendations on the prevention and control of O_(3)pollution in China based on relevant study results,and finally pointed out the shortcomings and future development prospects in this field in China.The overview study showed that the O_(3)formation sensitivity in some urban areas in China in recent years presented a gradual shifting tendency from the VOC-limited regime to the transition regime or the NO_(x)-limited regime due to the implementation of the O_(3)precursors emission reduction policies;O_(3)pollution control strategies and precursor control countermeasures should be formulated based on local conditions and the dynamic control capability of O_(3)pollution control measures should be improved.There are still some current deficiencies in the study field in China.Therefore,it is recommended that a stereoscopic monitoring network for atmospheric photochemical components should be further constructed and improved;the atmospheric chemical mechanisms should be vigorously developed,and standardized methods for determining the O_(3)formation sensitivity should be established in China in the near future.展开更多
Nitro-aromatic compounds(NACs)are among the major components of brown carbon(BrC)in the atmosphere,causing negative impacts on regional climate,air quality,and ecological health.Due to the extensive origins,it is stil...Nitro-aromatic compounds(NACs)are among the major components of brown carbon(BrC)in the atmosphere,causing negative impacts on regional climate,air quality,and ecological health.Due to the extensive origins,it is still a challenge to figure out the contributions and originating regions for different sources of atmospheric NACs.Here,field observations on fine particulate NACs were conducted at a coastal rural area in Qingdao,China in the winter of 2018 and 2019.The mean total concentrations of fine particulate nitro-aromatic compounds were 125.0±89.5 and 27.7±21.1 ng/m^(3)in the winter of 2018 and 2019,respectively.Among the measured eleven NACs,nitrophenols and nitrocatechols were the most abundant species.Variation characteristics and correlation analysis showed that humidity and anthropogenic primary emissions had significant influences on the NAC abundances.In this study,two tracing methods of the improved spatial concentration weighted trajectory(SCWT)model and the receptor model of positive matrix factorization(PMF)were combined to comprehensively understand the origins of NACs in fine particles at coastal Qingdao.Four major sources were identified,including coal combustion,biomass burning,vehicle exhaust,and secondary formation.Surprisingly,coal combustion was responsible for about half of the observed nitro-aromatic compounds,followed by biomass burning(~30%).The results by SCWT demonstrated that the coal combustion dominated NACs mainly originated from the Shandong peninsula and the areas to the north and southwest,while those dominated by biomass burning primarily came from local Qingdao and the areas to the west.展开更多
Climate change is increasing the frequency and intensity of heatwaves, raising concerns about their detrimental effects on air quality. However, a role for heatwave-human-environment interactions in air pollution exac...Climate change is increasing the frequency and intensity of heatwaves, raising concerns about their detrimental effects on air quality. However, a role for heatwave-human-environment interactions in air pollution exacerbation has not been established. In the summer of 2022, record-breaking heatwaves struck China and Europe. In this study, we use integrated observational data and machine learning to elucidate the formation mechanism underlying one of the most severe ozone pollution seasons on record in central eastern China, an area that encompasses approximately half of China's total population and sown land.Our findings reveal that the worsened ozone and nitrogen dioxide pollution resulted from a mismatch between energy demand and supply, which was driven by both heatwaves and energy policy-related factors. The observed adverse heatwave-energy-environment feedback loop highlights the need for the diversification of clean energy sources, more resilient energy structures and power policies, and further emission control to confront the escalating climate challenge in the future.展开更多
Regional ozone （O3） pollution has drawn increasing attention in China over the recent decade, but the contributions from urban pollution and biogenic emissions have not been clearly elucidated. To better understand ...Regional ozone （O3） pollution has drawn increasing attention in China over the recent decade, but the contributions from urban pollution and biogenic emissions have not been clearly elucidated. To better understand the formation of the regional O3 problem in the North China Plain （NCP）, intensive field measurements of O3 and related parameters were conducted at a rural site downwind of Ji＇nan, the capital city of Shandong province, in the summer of 2013. Markedly severe 03 pollution was recorded, with the 03 mixing ratios exceeding the Chinese national ambient air quality standard on 28 days （a frequency of 78%） and with a maximum hourly value of 198 ppbv. Extensive regional transport of well-processed urban plumes to the site was identified. An observation-constrained chemical box model was deployed to evaluate in situ photochemical O3 production on two episodes. The results show that the in situ formation accounted for approximately 46% of the observed O3 accumulation, while the remainder （54%） was contributed by regional transport of the O3-laden urban plumes. The in situ ozone production was in a mixed controlled regime that reducing either NOx or VOCs would lead to a reduction of ozone formation. Biogenic VOCs played an important role in the local ozone formation. This study demonstrates the significant mixed effects of both anthropogenic pollution from urban zones and biogenic emission in rural areas on the regional 03 pollution in the NCP region, and may have general applicability in facilitating the understanding of the formation of secondary pollution over China.展开更多
Peroxyacetyl nitrate （PAN）, as a major secondary pollutant, has gained increasing worldwide attentions, but relevant studies in China are still quite limited. During winter of 2015 to summer of 2016, the ambient lev...Peroxyacetyl nitrate （PAN）, as a major secondary pollutant, has gained increasing worldwide attentions, but relevant studies in China are still quite limited. During winter of 2015 to summer of 2016, the ambient levels of PAN were measured continuously by an automatic gas chromatograph equipped with an electron capture detector （GC-ECD） analyzer at an urban site in Jinan （China）, with related parameters including concentrations of 03, NO, NO2, PM2.5, HONO, the photolysis rate constant of NO2 and meteorological factors observed concurrently. The mean and maximum values of PAN concentration were （1.89 ± 1.42） and 9.61 ppbv respectively in winter, and （2.54 ± 1.44） and 13.47 ppbv respectively in summer. Unusually high levels of PAN were observed during severe haze episodes in winter, and the formation mechanisms of them were emphatically discussed, Study showed that high levels of PAN in winter were mainly caused by local accumulation and strong photochemical reactions during haze episodes, while mass transport played only a minor role. Accelerated photochemical reactions （compared to winter days without haze） during haze episodes were deduced by the higher concentrations but shorter lifetimes of pAN, which was further supported by the sufficient solar radiation in the photolysis band along with the high concentrations of precursors （NO2, VOCs） and HONO during haze episodes. In addition, significant PAN accumulation during calm weather of haze episodes was verified by meteorological data.展开更多
Nitryl chloride(ClNO2)is a product of nocturnal halogen activation of nitrogen oxides and has potential to impact atmospheric photochemistry.Here we report the first observation result of ClNO2in an Asian environment....Nitryl chloride(ClNO2)is a product of nocturnal halogen activation of nitrogen oxides and has potential to impact atmospheric photochemistry.Here we report the first observation result of ClNO2in an Asian environment.The measurements were made with a thermal decomposition chemical ionization mass spectrometer at a coastal site in southern China during late summer of 2012.A clear diurnal pattern of ClNO2was observed with nighttime 1-min average mixing ratio up to 1997 pptv,which is among the highest values ever reported in the world.The elevated ClNO2mixing ratios were observed in plumes from Hong Kong and the Pearl River Delta region compared to the lower levels in maritime air.Calculations suggest that the production of chlorine atom from photolysis of ClNO2in the early morning exceeds the production of hydroxyl radical via ozone photolysis by several factors.Therefore,ClNO2plays an important role in jump-starting the atmospheric photochemistry in polluted marine boundary layer of southern China.展开更多
Methane(CH_(4))and carbon dioxide(CO_(2))are the two most important greenhouse gases(GHGs).To examine the variation characteristics of CH_(4)and CO_(2)in the coastal South China Sea,atmospheric CH_(4)and CO_(2)measure...Methane(CH_(4))and carbon dioxide(CO_(2))are the two most important greenhouse gases(GHGs).To examine the variation characteristics of CH_(4)and CO_(2)in the coastal South China Sea,atmospheric CH_(4)and CO_(2)measurements were performed in Bohe(BH),Guangdong,China,in summer 2021.By using an adaptive data analysis method,the diurnal patterns of CH_(4)and CO_(2)were clearly extracted and analysed in relation to the sea breeze(SB)and land breeze(LB),respectively.The average concentrations of CH_(4)and CO_(2)were 1876.91±31.13 ppb and 407.99±4.24 ppm during SB,and 1988.12±109.92 ppb and 421.54±14.89 ppm during LB,respectively.The values of CH_(4)and CO_(2)during SB basically coincided with the values and trends of marine background sites,showing that the BH station could serve as an ideal site for background GHG monitoring and dynamic analysis.The extracted diurnal variations in CH_(4)and CO_(2)showed sunrise high and sunset low patterns(with peaks at 5:00–7:00)during LB but mid-morning high and evening low patterns(with peaks at 9:00)during SB.The diurnal amplitude changes in both CH_(4)and CO_(2)during LB were almost two to three times those during SB.Wind direction significantly modulated the diurnal variations in CH_(4)and CO_(2).The results in this study provide a new way to examine the variations in GHGs on different timescales and can also help us gain a better understanding of GHG sources and distributions in the South China Sea.展开更多
Heterogeneous reactions of NO2 on different surfaces play an important role in atmospheric NOxremoval and HONO formation,having profound impacts on photochemistry in polluted urban areas.Previous studies have suggeste...Heterogeneous reactions of NO2 on different surfaces play an important role in atmospheric NOxremoval and HONO formation,having profound impacts on photochemistry in polluted urban areas.Previous studies have suggested that the NO2 uptake on the ground or aerosol surfaces could be a dominant source for elevated HONO during the daytime.However,the uptake behavior of NO2 varies with different surfaces,and different uptake coefficients were used or derived in different studies.To obtain a more holistic picture of heterogeneous NO2 uptake on different surfaces,a series of laboratory experiments using different flow tube reactors was conducted,and the NO2 uptake coefficients(γ)were determined on inorganic particles,sea water and urban grime.The results showed that heterogeneous reactions on those surfaces were generally weak in dark conditions,with the measuredγvaried from<10-8 to 3.2×10-7 under different humidity.A photo-enhanced uptake of NO2 on urban grime was observed,with the obvious formation of HONO and NO from the heterogeneous reaction.The photo-enhancedγwas measured to be 1.9×10-6 at 5%relative humidity(RH)and 5.8×10-6 at 70%RH on urban grime,showing a positive RH dependence for both NO2 uptake and HONO formation.The results demonstrate an important role of urban grime in the daytime NO2-to-HONO conversion,and could be helpful to explain the unknown daytime HONO source in the polluted urban area.展开更多
To understand the size-resolved aerosol ionic composition and the factors influencing secondary aerosol formation in the upper boundary layer in South Central China, size-segregated aerosol samples were collected usin...To understand the size-resolved aerosol ionic composition and the factors influencing secondary aerosol formation in the upper boundary layer in South Central China, size-segregated aerosol samples were collected using a micro-orifice uniform deposit irnpactor （MOUDI） in spring 2009 at the summit of Mount Heng （1269 m asl）, followed by subsequent laboratory analyses of 13 inorganic and organic water-soluble ions. During non- dust-storm periods, the average PM1.8 concentration was 41.8 μg·m^-3, contributing to 55% of the PM10. Sulfates, nitrates, and ammonium, the dominant ions in the fine particles, amounted to 46.8% of the PM1.8. Compared with Mount Tai in the North China Plain, the concentrations of both fine and coarse particles and the ions contained therein were substantially lower. When the air masses from Southeast Asia prevailed, intensive biomass burning there led to elevated concentrations of sulfates, nitrates, ammonium, potassium, and chloride in the fine particles at Mount Heng. The air masses originating from the north Gobi brought heavy dust storms that resulted in the remarkable production of sulfates, ammonium, methane sulfonic acid, and oxalates in the coarse particles. Generally, the sulfates were primarily produced in the form of （NH4）2SO4 in the droplet mode via heterogeneous aqueous reactions. Only approximately one-third of the nitrates were distributed in the fine mode, and high humidity facilitated the secondary formation of fine nitrates. The heterogeneous formation of coarse nitrates and ammonium on dry alkaline dust surfaces was found to be less efficient than that on the coarse particles during non-dust-storm periods.展开更多
Peroxyacetyl nitrate （PAN） is an important indicator of photochemical smog and has adverse effects on human health and vegetation growth. A rapid and h!ghly selective technique of thermal dissociation chemical ioniz...Peroxyacetyl nitrate （PAN） is an important indicator of photochemical smog and has adverse effects on human health and vegetation growth. A rapid and h!ghly selective technique of thermal dissociation chemical ionization mass spectrometry （TD-CIMS） was recently developed to measure the abundance of PAN in real time; however, it may be subject to artifact in the presence of nitric oxide （NO）. In this study, we tested the interference of the PAN signal induced by NO, evaluated the performance of TD- CIMS in an urban environment, and investigated the concentration and formation of PAN in urban Hong Kong. NO caused a significant underestimation of the PAN signal in TD-CIMS, with the underestimation increasing sharply with NO concentration and decreasing slightly with PAN abundance. A formula was derived to link the loss of PAN signal with the concentrations of NO and PAN, which can be used for data correction in PAN measurements. The corrected PAN data from TD- CIMS were consistent with those from the commonly used gas chromatography with electron capture detection, which confirms the utility of TD-CIMS in an urban environment in which NO is abundant. In autumn of 2010, the hourly average PAN mixing ratio varied from 0.06 ppbv to 5.17 ppbv, indicating the occurrence of photochemical pollution in urban Hong Kong. The tbrmation efficiency of PAN during pollution episodes was as high as 3.9 to 5.9 ppbv per 100 ppbv ozone. The efficiency showed a near-linear increase with NO, concentration, suggesting a control policy of NO,. reduction for PAN pollution.展开更多
To understand the pollution characteristics of particulate matter emitted from outdoor barbecue conking in eastern China, measurements of the PM2.5 mass concentration, the number concentration of particles with a diam...To understand the pollution characteristics of particulate matter emitted from outdoor barbecue conking in eastern China, measurements of the PM2.5 mass concentration, the number concentration of particles with a diameter of 0.01 to 1.0 pm, and the particle size distribution from 0.3 to 25 μm were carried out at seven barbecue restaurants in urban Jinan. The average PM2.5 mass concentration and sub-micron particle number concentrations at a distance of 1 m from the grills were 250 to 1083μtg/m-3 and 0.90 × 105 to 2.23 × 105 cm 3 respectively, which were much higher than those in the ambient air of the urban area. Compared to the ambient atmosphere, barbecue cooking emitted very high levels of particles with a larger increase in the concentrations of super-micron particles than that of sub-micron particles. The super-micron particle number concentrations at the barbecue restaurants were 10 to I O0 times higher than those observed in the ambient urban atmosphere. The barbecue smoke had a significant effect on the particle concentrations in the surrctindng region.. Both mass and number concentrations of particles exhibited maximum values immediately-near the barbecue grills and often reached a peak at a distance of 10 to 15 m. The removal efficiency of a range hood for the cooking particles was tested in an indoor kitchen. The range hood effectively cleaned the particulate matter pollution caused by cooking with a removal efficiency larger than 80%, Therefore, the use of a range hood is recommended for outdoor barbecue restaurants coupled with a smoke purifier to clean the emitted high concentrations of particles.展开更多
Exploring the nonlinear relationship between air pollution and precursor emissions in Qingdao,eastern China is crucial for improving air quality.We simulated 32 emission reduction scenarios based on different volatile...Exploring the nonlinear relationship between air pollution and precursor emissions in Qingdao,eastern China is crucial for improving air quality.We simulated 32 emission reduction scenarios based on different volatile organic compound(VOC)and nitrogen oxide(NO_(x))emission reduction ratios using the Weather Research and Forecasting-Comprehensive Air Quality Model Extensions model.The emission reduction of VOCs was beneficial for reducing fine particulate matter(PM_(2.5))concentration in January and ozone(O_(3))concentration in June.However,NO_(x)must be reduced by at least 48%and 70%to decrease PM_(2.5)and O_(3)concentrations,respectively,when VOCs are not reduced.The responses of PM_(2.5)and O_(3)concentrations to emission reductions from different sources were also evaluated.The reduction in VOC emissions from different sources decreased the PM_(2.5)concentration in January,and O_(3)concertation in June,while NO_(x)reduction resulted in an increase.Controlling VOC emissions from industry has a positive effect on improving local PM_(2.5)and O_(3),while the emission reductions of NO_(x)from transportation and industry are not conducive to reducing PM_(2.5)and O_(3)concentrations.The synergistic emission reduction pathways for NO_(x)and VOCs during PM_(2.5)and O_(3)combined pollution were also analyzed.The VOC and NO_(x)emission reductions were beneficial for reducing the comprehensive Air Quality Index(sAQI)values.When the NO_(x)emission reduction was large,the sAQI improvement gradually exceeded that of VOCs.A collaborative optimization path should be adopted that focuses on controlling VOCs first,and further control of combined pollution should depend on the deep reduction of NO_(x).展开更多
Elevated concentrations of formaldehyde and other carbonyl compounds are frequently observed in the marine atmosphere but are often significantly underestimated by atmospheric models.To evaluate the potential impact o...Elevated concentrations of formaldehyde and other carbonyl compounds are frequently observed in the marine atmosphere but are often significantly underestimated by atmospheric models.To evaluate the potential impact of marine sources on atmospheric formaldehyde,high-resolution measurements were conducted at a coastal site(~15 m from the sea)during the summer in Qingdao,China.Observed formaldehyde levels averaged 2.4±0.9 ppbv(1 ppbv=10^(-9)L L^(-1)),with peaks reaching 6.8 ppbv.Backward trajectories indicate that formaldehyde concentrations remained high in marine air masses.Formaldehyde exhibited weak correlations with primary pollutants such as NO and CO but showed strong correlations with marine tracers,notably methyl ethyl ketone and 1-butene.Chamber experiments confirmed that the photodecomposition of Enteromorpha released large amounts of formaldehyde and marine tracer species.When normalized to acetylene,the levels of formaldehyde,1-butene,and MEK increased by factors of 3.8,8.1,and 3.5,respectively.Results from an observation-based chemical box model simulation,which utilizes the Master Chemical Mechanism(MCM),revealed that formaldehyde contributes 56% to the primary source of HO_(2)radicals,while neglecting formaldehyde chemistry would lead to a 15% reduction in coastal ozone production rates.This study interlinks oceanic biology and atmospheric chemistry,advancing the understanding of the ocean’s role as a significant source of organic compounds and its contribution to carbon cycling.展开更多
基金funded by the National Natural Science Foundation of China[grant number 42075094]the China Postdoctoral Science Foundation[grant number 2021M691921]+1 种基金the Ministry of Ecology and Environment of the People’s Republic of China[grant number DQGG202121]the Dongying Ecological and Environmental Bureau[grant number 2021DFKY-0779]。
文摘The petroleum industry is a significant source of anthropogenic volatile organic compounds(VOCs),but up to now,its exact impact on urban VOCs and ozone(O_(3))remains unclear.This study conducted year-long VOC ob-servations in Dongying,China,a petroleum industrial region.The VOCs from the petroleum industry(oil and gas volatilization and petrochemical production)were identified by employing the positive matrix factorization model,and their contribution to O_(3) formation was quantitatively evaluated using an observation-based chemical box model.The observed annual average concentration of VOCs was 68.6±63.5 ppbv,with a maximum daily av-erage of 335.3 ppbv.The petroleum industry accounted for 66.5%of total VOCs,contributing 54.9%from oil and gas evaporation and 11.6%from petrochemical production.Model results indicated that VOCs from the petroleum industry contributed to 31%of net O_(3) production,with 21.3%and 34.2%contributions to HO_(2)+NO and RO_(2)+NO pathways,respectively.The larger impact on the RO_(2) pathway is primarily due to the fact that OH+VOCs ac-count for 86.9%of the primary source of RO_(2).This study highlights the critical role of controlling VOCs from the petroleum industry in urban O_(3) pollution,especially those from previously overlooked low-reactivity alkanes.
文摘Fine particulate matter(PM_(2.5))and ground-level ozone(O_(3))are the primary air pollutants that degrade air quality in urban and regional areas of China.Since the implementation of the“Air Pollution Preven-tion and Control Action Plan”in 2013,ambient concentrations of PM_(2.5)have significantly decreased across China.However,O_(3)levels exhibited an upward trend until 2019 and have since remained elevated,despite the COVID-19 pandemic.Currently,no city in China has achieved the World Health Organization’s guidelines for PM_(2.5)(24-hour mean of 15μg m^(−3)and annual mean of 5μg m^(−3))and O_(3)(8-hour mean of 100μg m^(−3)).Therefore,more rigorous measures are necessary to alleviate PM_(2.5)and O_(3)pollution in China.
基金This work is supported by the National Natural Science Foundation of China(No.62071280,No.61602287)the Major Scientific and Technological Innovation Project of Shandong Province(No.2020CXGC010115)the Guangxi Key Laboratory of Cryptography and Information Security(GCIS201901).
文摘With the development of big data and cloud computing technology,more and more users choose to store data on cloud servers,which brings much convenience to their management and use of data,and also the risk of data leakage.A common method to prevent data leakage is to encrypt the data before uploading it,but the traditional encryption method is often not conducive to data sharing and querying.In this paper,a new kind of Attribute-Based Encryption(ABE)scheme,which is called the Sub-String Searchable ABE(SSS-ABE)scheme,is proposed for the sharing and querying of the encrypted data.In the SSS-ABE scheme,the data owner encrypts the data under an access structure,and only the data user who satisfies the access structure can query and decrypt it.The data user can make a substring query on the whole ciphertext without setting keywords in advance.In addition,the outsourcing method is also introduced to reduce the local computation of the decryption process so that the outsourcing SSS-ABE scheme can be applied to IoT devices.
基金supported by the National Research Program for Key Issues in Air Pollution Control(No.DQGG202121)the Beijing Municipal Science&Technology Commission(No.Z181100005418015)+1 种基金National Natural Science Foundation of China(No.42075094)the National Research Program for Key Issue in Air Pollution Control(No.DQGG2021101)。
文摘Observation-based method for O_(3)formation sensitivity research is an important tool to analyze the causes of ground-level O_(3)pollution,which has broad application potentials in determining the O_(3)pollution formation mechanism and developing prevention and control strategies.This paper outlined the development history of research on O_(3)formation sensitivity based on observational methods,described the principle and applicability of the methodology,summarized the relative application results in China and provided recommendations on the prevention and control of O_(3)pollution in China based on relevant study results,and finally pointed out the shortcomings and future development prospects in this field in China.The overview study showed that the O_(3)formation sensitivity in some urban areas in China in recent years presented a gradual shifting tendency from the VOC-limited regime to the transition regime or the NO_(x)-limited regime due to the implementation of the O_(3)precursors emission reduction policies;O_(3)pollution control strategies and precursor control countermeasures should be formulated based on local conditions and the dynamic control capability of O_(3)pollution control measures should be improved.There are still some current deficiencies in the study field in China.Therefore,it is recommended that a stereoscopic monitoring network for atmospheric photochemical components should be further constructed and improved;the atmospheric chemical mechanisms should be vigorously developed,and standardized methods for determining the O_(3)formation sensitivity should be established in China in the near future.
基金supported by the Natural Science Foundation of Shandong Province (No.ZR2020YQ30)the National Natural Science Foundation of China (Nos.42005089,41775118)+1 种基金the Youth Innovation Program of Universities in Shandong Province (No.2019KJD007)received financial support from Shandong University (No.2020QNQT012)。
文摘Nitro-aromatic compounds(NACs)are among the major components of brown carbon(BrC)in the atmosphere,causing negative impacts on regional climate,air quality,and ecological health.Due to the extensive origins,it is still a challenge to figure out the contributions and originating regions for different sources of atmospheric NACs.Here,field observations on fine particulate NACs were conducted at a coastal rural area in Qingdao,China in the winter of 2018 and 2019.The mean total concentrations of fine particulate nitro-aromatic compounds were 125.0±89.5 and 27.7±21.1 ng/m^(3)in the winter of 2018 and 2019,respectively.Among the measured eleven NACs,nitrophenols and nitrocatechols were the most abundant species.Variation characteristics and correlation analysis showed that humidity and anthropogenic primary emissions had significant influences on the NAC abundances.In this study,two tracing methods of the improved spatial concentration weighted trajectory(SCWT)model and the receptor model of positive matrix factorization(PMF)were combined to comprehensively understand the origins of NACs in fine particles at coastal Qingdao.Four major sources were identified,including coal combustion,biomass burning,vehicle exhaust,and secondary formation.Surprisingly,coal combustion was responsible for about half of the observed nitro-aromatic compounds,followed by biomass burning(~30%).The results by SCWT demonstrated that the coal combustion dominated NACs mainly originated from the Shandong peninsula and the areas to the north and southwest,while those dominated by biomass burning primarily came from local Qingdao and the areas to the west.
基金supported by Hong Kong Research Grants Council (T24-504/17-N)National Natural Science Foundation of China (41922051)National Key Research and Development Program of China (2022YFC3701101)。
文摘Climate change is increasing the frequency and intensity of heatwaves, raising concerns about their detrimental effects on air quality. However, a role for heatwave-human-environment interactions in air pollution exacerbation has not been established. In the summer of 2022, record-breaking heatwaves struck China and Europe. In this study, we use integrated observational data and machine learning to elucidate the formation mechanism underlying one of the most severe ozone pollution seasons on record in central eastern China, an area that encompasses approximately half of China's total population and sown land.Our findings reveal that the worsened ozone and nitrogen dioxide pollution resulted from a mismatch between energy demand and supply, which was driven by both heatwaves and energy policy-related factors. The observed adverse heatwave-energy-environment feedback loop highlights the need for the diversification of clean energy sources, more resilient energy structures and power policies, and further emission control to confront the escalating climate challenge in the future.
基金funded by the Taishan Scholar Grand (No. ts20120552)the National Natural Science Foundation of China (No. 41375126)+2 种基金supported by the National Natural Science Foundation of China (No. 41675118)the Qilu Youth Talent Programme of Shandong Universitythe Jiangsu Collaborative Innovation Center for Climate Change
文摘Regional ozone （O3） pollution has drawn increasing attention in China over the recent decade, but the contributions from urban pollution and biogenic emissions have not been clearly elucidated. To better understand the formation of the regional O3 problem in the North China Plain （NCP）, intensive field measurements of O3 and related parameters were conducted at a rural site downwind of Ji＇nan, the capital city of Shandong province, in the summer of 2013. Markedly severe 03 pollution was recorded, with the 03 mixing ratios exceeding the Chinese national ambient air quality standard on 28 days （a frequency of 78%） and with a maximum hourly value of 198 ppbv. Extensive regional transport of well-processed urban plumes to the site was identified. An observation-constrained chemical box model was deployed to evaluate in situ photochemical O3 production on two episodes. The results show that the in situ formation accounted for approximately 46% of the observed O3 accumulation, while the remainder （54%） was contributed by regional transport of the O3-laden urban plumes. The in situ ozone production was in a mixed controlled regime that reducing either NOx or VOCs would lead to a reduction of ozone formation. Biogenic VOCs played an important role in the local ozone formation. This study demonstrates the significant mixed effects of both anthropogenic pollution from urban zones and biogenic emission in rural areas on the regional 03 pollution in the NCP region, and may have general applicability in facilitating the understanding of the formation of secondary pollution over China.
基金supported by the National Key R&D Program of China(No.2016YFC0202700)the National Natural Science Foundation of China(Nos.41375126,21527814,91743202)the H2020 Marie Sklodowska-Curie Actions(No.H2020-MSCARISE-2015-690958)
文摘Peroxyacetyl nitrate （PAN）, as a major secondary pollutant, has gained increasing worldwide attentions, but relevant studies in China are still quite limited. During winter of 2015 to summer of 2016, the ambient levels of PAN were measured continuously by an automatic gas chromatograph equipped with an electron capture detector （GC-ECD） analyzer at an urban site in Jinan （China）, with related parameters including concentrations of 03, NO, NO2, PM2.5, HONO, the photolysis rate constant of NO2 and meteorological factors observed concurrently. The mean and maximum values of PAN concentration were （1.89 ± 1.42） and 9.61 ppbv respectively in winter, and （2.54 ± 1.44） and 13.47 ppbv respectively in summer. Unusually high levels of PAN were observed during severe haze episodes in winter, and the formation mechanisms of them were emphatically discussed, Study showed that high levels of PAN in winter were mainly caused by local accumulation and strong photochemical reactions during haze episodes, while mass transport played only a minor role. Accelerated photochemical reactions （compared to winter days without haze） during haze episodes were deduced by the higher concentrations but shorter lifetimes of pAN, which was further supported by the sufficient solar radiation in the photolysis band along with the high concentrations of precursors （NO2, VOCs） and HONO during haze episodes. In addition, significant PAN accumulation during calm weather of haze episodes was verified by meteorological data.
基金supported by the Research Grants Council of Hong Kong(PolyU5015/12P)
文摘Nitryl chloride(ClNO2)is a product of nocturnal halogen activation of nitrogen oxides and has potential to impact atmospheric photochemistry.Here we report the first observation result of ClNO2in an Asian environment.The measurements were made with a thermal decomposition chemical ionization mass spectrometer at a coastal site in southern China during late summer of 2012.A clear diurnal pattern of ClNO2was observed with nighttime 1-min average mixing ratio up to 1997 pptv,which is among the highest values ever reported in the world.The elevated ClNO2mixing ratios were observed in plumes from Hong Kong and the Pearl River Delta region compared to the lower levels in maritime air.Calculations suggest that the production of chlorine atom from photolysis of ClNO2in the early morning exceeds the production of hydroxyl radical via ozone photolysis by several factors.Therefore,ClNO2plays an important role in jump-starting the atmospheric photochemistry in polluted marine boundary layer of southern China.
基金supported by the Basic Scientific Fund for National Public Research Institutes of China(No.2018Q01)the Natural Science Foundation of Shandong Province(China)(No.ZR202102190358)+2 种基金the National Natural Science Foundation of China(No.41821004)the international cooperation project on Indo-Pacific Ocean environmental variability and air-sea interactions(China)(No.GASIIPOVAI-05)the Aoshan Talents Cultivation Excellent Scholar Program supported by Qingdao National Laboratory for Marine Science and Technology(China)(No.2017ASTCP-ES04).
文摘Methane(CH_(4))and carbon dioxide(CO_(2))are the two most important greenhouse gases(GHGs).To examine the variation characteristics of CH_(4)and CO_(2)in the coastal South China Sea,atmospheric CH_(4)and CO_(2)measurements were performed in Bohe(BH),Guangdong,China,in summer 2021.By using an adaptive data analysis method,the diurnal patterns of CH_(4)and CO_(2)were clearly extracted and analysed in relation to the sea breeze(SB)and land breeze(LB),respectively.The average concentrations of CH_(4)and CO_(2)were 1876.91±31.13 ppb and 407.99±4.24 ppm during SB,and 1988.12±109.92 ppb and 421.54±14.89 ppm during LB,respectively.The values of CH_(4)and CO_(2)during SB basically coincided with the values and trends of marine background sites,showing that the BH station could serve as an ideal site for background GHG monitoring and dynamic analysis.The extracted diurnal variations in CH_(4)and CO_(2)showed sunrise high and sunset low patterns(with peaks at 5:00–7:00)during LB but mid-morning high and evening low patterns(with peaks at 9:00)during SB.The diurnal amplitude changes in both CH_(4)and CO_(2)during LB were almost two to three times those during SB.Wind direction significantly modulated the diurnal variations in CH_(4)and CO_(2).The results in this study provide a new way to examine the variations in GHGs on different timescales and can also help us gain a better understanding of GHG sources and distributions in the South China Sea.
基金supported by the French National Research Agency/Research Grants Council of Hong Kong Special Administrative Region,China(ANR/RGC)Joint Research Scheme(project A-PolyU502/16-SEAM)National Natural Science Foundation of China(Nos.91744204,91844301)+1 种基金the Research Grants Council of Hong Kong Special Administrative Region,China(Nos.T24/504/17,15265516,C5022-14G)。
文摘Heterogeneous reactions of NO2 on different surfaces play an important role in atmospheric NOxremoval and HONO formation,having profound impacts on photochemistry in polluted urban areas.Previous studies have suggested that the NO2 uptake on the ground or aerosol surfaces could be a dominant source for elevated HONO during the daytime.However,the uptake behavior of NO2 varies with different surfaces,and different uptake coefficients were used or derived in different studies.To obtain a more holistic picture of heterogeneous NO2 uptake on different surfaces,a series of laboratory experiments using different flow tube reactors was conducted,and the NO2 uptake coefficients(γ)were determined on inorganic particles,sea water and urban grime.The results showed that heterogeneous reactions on those surfaces were generally weak in dark conditions,with the measuredγvaried from<10-8 to 3.2×10-7 under different humidity.A photo-enhanced uptake of NO2 on urban grime was observed,with the obvious formation of HONO and NO from the heterogeneous reaction.The photo-enhancedγwas measured to be 1.9×10-6 at 5%relative humidity(RH)and 5.8×10-6 at 70%RH on urban grime,showing a positive RH dependence for both NO2 uptake and HONO formation.The results demonstrate an important role of urban grime in the daytime NO2-to-HONO conversion,and could be helpful to explain the unknown daytime HONO source in the polluted urban area.
文摘To understand the size-resolved aerosol ionic composition and the factors influencing secondary aerosol formation in the upper boundary layer in South Central China, size-segregated aerosol samples were collected using a micro-orifice uniform deposit irnpactor （MOUDI） in spring 2009 at the summit of Mount Heng （1269 m asl）, followed by subsequent laboratory analyses of 13 inorganic and organic water-soluble ions. During non- dust-storm periods, the average PM1.8 concentration was 41.8 μg·m^-3, contributing to 55% of the PM10. Sulfates, nitrates, and ammonium, the dominant ions in the fine particles, amounted to 46.8% of the PM1.8. Compared with Mount Tai in the North China Plain, the concentrations of both fine and coarse particles and the ions contained therein were substantially lower. When the air masses from Southeast Asia prevailed, intensive biomass burning there led to elevated concentrations of sulfates, nitrates, ammonium, potassium, and chloride in the fine particles at Mount Heng. The air masses originating from the north Gobi brought heavy dust storms that resulted in the remarkable production of sulfates, ammonium, methane sulfonic acid, and oxalates in the coarse particles. Generally, the sulfates were primarily produced in the form of （NH4）2SO4 in the droplet mode via heterogeneous aqueous reactions. Only approximately one-third of the nitrates were distributed in the fine mode, and high humidity facilitated the secondary formation of fine nitrates. The heterogeneous formation of coarse nitrates and ammonium on dry alkaline dust surfaces was found to be less efficient than that on the coarse particles during non-dust-storm periods.
基金This work was supported by the Environment and Conservation Fund of Hung Kong （Project No. 2009-07）, National Natural Science Foundation of China （Grant Nos. 41275123, 21407094 and 91544213）, China Postdoctoral Science Foundation （No. 2014M561932）, and the Jiangsu Collaborative Innovation Center for Climate Change. The authors thank Dr. Pamela Holt for proofreading the manuscript.
文摘Peroxyacetyl nitrate （PAN） is an important indicator of photochemical smog and has adverse effects on human health and vegetation growth. A rapid and h!ghly selective technique of thermal dissociation chemical ionization mass spectrometry （TD-CIMS） was recently developed to measure the abundance of PAN in real time; however, it may be subject to artifact in the presence of nitric oxide （NO）. In this study, we tested the interference of the PAN signal induced by NO, evaluated the performance of TD- CIMS in an urban environment, and investigated the concentration and formation of PAN in urban Hong Kong. NO caused a significant underestimation of the PAN signal in TD-CIMS, with the underestimation increasing sharply with NO concentration and decreasing slightly with PAN abundance. A formula was derived to link the loss of PAN signal with the concentrations of NO and PAN, which can be used for data correction in PAN measurements. The corrected PAN data from TD- CIMS were consistent with those from the commonly used gas chromatography with electron capture detection, which confirms the utility of TD-CIMS in an urban environment in which NO is abundant. In autumn of 2010, the hourly average PAN mixing ratio varied from 0.06 ppbv to 5.17 ppbv, indicating the occurrence of photochemical pollution in urban Hong Kong. The tbrmation efficiency of PAN during pollution episodes was as high as 3.9 to 5.9 ppbv per 100 ppbv ozone. The efficiency showed a near-linear increase with NO, concentration, suggesting a control policy of NO,. reduction for PAN pollution.
文摘To understand the pollution characteristics of particulate matter emitted from outdoor barbecue conking in eastern China, measurements of the PM2.5 mass concentration, the number concentration of particles with a diameter of 0.01 to 1.0 pm, and the particle size distribution from 0.3 to 25 μm were carried out at seven barbecue restaurants in urban Jinan. The average PM2.5 mass concentration and sub-micron particle number concentrations at a distance of 1 m from the grills were 250 to 1083μtg/m-3 and 0.90 × 105 to 2.23 × 105 cm 3 respectively, which were much higher than those in the ambient air of the urban area. Compared to the ambient atmosphere, barbecue cooking emitted very high levels of particles with a larger increase in the concentrations of super-micron particles than that of sub-micron particles. The super-micron particle number concentrations at the barbecue restaurants were 10 to I O0 times higher than those observed in the ambient urban atmosphere. The barbecue smoke had a significant effect on the particle concentrations in the surrctindng region.. Both mass and number concentrations of particles exhibited maximum values immediately-near the barbecue grills and often reached a peak at a distance of 10 to 15 m. The removal efficiency of a range hood for the cooking particles was tested in an indoor kitchen. The range hood effectively cleaned the particulate matter pollution caused by cooking with a removal efficiency larger than 80%, Therefore, the use of a range hood is recommended for outdoor barbecue restaurants coupled with a smoke purifier to clean the emitted high concentrations of particles.
基金funded by the Shandong Postdoctoral Science Foundation(No.SDCX-ZG-202303008).
文摘Exploring the nonlinear relationship between air pollution and precursor emissions in Qingdao,eastern China is crucial for improving air quality.We simulated 32 emission reduction scenarios based on different volatile organic compound(VOC)and nitrogen oxide(NO_(x))emission reduction ratios using the Weather Research and Forecasting-Comprehensive Air Quality Model Extensions model.The emission reduction of VOCs was beneficial for reducing fine particulate matter(PM_(2.5))concentration in January and ozone(O_(3))concentration in June.However,NO_(x)must be reduced by at least 48%and 70%to decrease PM_(2.5)and O_(3)concentrations,respectively,when VOCs are not reduced.The responses of PM_(2.5)and O_(3)concentrations to emission reductions from different sources were also evaluated.The reduction in VOC emissions from different sources decreased the PM_(2.5)concentration in January,and O_(3)concertation in June,while NO_(x)reduction resulted in an increase.Controlling VOC emissions from industry has a positive effect on improving local PM_(2.5)and O_(3),while the emission reductions of NO_(x)from transportation and industry are not conducive to reducing PM_(2.5)and O_(3)concentrations.The synergistic emission reduction pathways for NO_(x)and VOCs during PM_(2.5)and O_(3)combined pollution were also analyzed.The VOC and NO_(x)emission reductions were beneficial for reducing the comprehensive Air Quality Index(sAQI)values.When the NO_(x)emission reduction was large,the sAQI improvement gradually exceeded that of VOCs.A collaborative optimization path should be adopted that focuses on controlling VOCs first,and further control of combined pollution should depend on the deep reduction of NO_(x).
基金supported by the National Natural Science Foundation of China(42061160478 and 42105106)the Hong Kong Scholars Program(P0039835),the China Postdoctoral Science Foundation(2021M691921)the Shandong Provincial Natural Science Foundation(ZR2020QD059)。
文摘Elevated concentrations of formaldehyde and other carbonyl compounds are frequently observed in the marine atmosphere but are often significantly underestimated by atmospheric models.To evaluate the potential impact of marine sources on atmospheric formaldehyde,high-resolution measurements were conducted at a coastal site(~15 m from the sea)during the summer in Qingdao,China.Observed formaldehyde levels averaged 2.4±0.9 ppbv(1 ppbv=10^(-9)L L^(-1)),with peaks reaching 6.8 ppbv.Backward trajectories indicate that formaldehyde concentrations remained high in marine air masses.Formaldehyde exhibited weak correlations with primary pollutants such as NO and CO but showed strong correlations with marine tracers,notably methyl ethyl ketone and 1-butene.Chamber experiments confirmed that the photodecomposition of Enteromorpha released large amounts of formaldehyde and marine tracer species.When normalized to acetylene,the levels of formaldehyde,1-butene,and MEK increased by factors of 3.8,8.1,and 3.5,respectively.Results from an observation-based chemical box model simulation,which utilizes the Master Chemical Mechanism(MCM),revealed that formaldehyde contributes 56% to the primary source of HO_(2)radicals,while neglecting formaldehyde chemistry would lead to a 15% reduction in coastal ozone production rates.This study interlinks oceanic biology and atmospheric chemistry,advancing the understanding of the ocean’s role as a significant source of organic compounds and its contribution to carbon cycling.
