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Rural vehicle emission as an important driver for the variations of summertime tropospheric ozone in the Beijing-Tianjin-Hebei region during 2014-2019

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Journal of Environmental Sciences 2022年第4期34卷 126-135页

作者： Yifei Song Yuanyuan Zhang Junfeng liu Chenglong Zhang Chengtang Liu Pengfei liu Yujing Mu Research Center for Eco-Environmental Sciences Chinese Academy of SciencesBeijing 100085China Center for Excellence in Urban Atmospheric Environment Institute of Urban EnvironmentChinese Academy of SciencesXiamen 361021China University of Chinese Academy of Sciences Beijing 100049China

Tropospheric ozone(O_(3))pollution is increasing in the Beijing-Tianjin-Hebei(BTH)region despite a significant decline in atmospheric fine aerosol particles(PM_(2.5))in recent years.However,the intrinsic reason for the elevation of the regional O_(3)is still unclear.In this study,we analyzed the spatio-temporal variations of tropospheric O_(3)and relevant pollutants(PM_(2.5),NO_(2),and CO)in the BTH region based on monitoring data from the China Ministry of Ecology and Environment during the period of 2014-2019.The results showed that summertime O_(3)concentrations were constant in Beijing(BJ,0.06μg/(m^(3)·year))but increased significantly in Tianjin(TJ,9.09μg/(m^(3)·year))and Hebei(HB,6.06μg/(m3·year)).Distinct O_(3)trends between Beijing and other cities in BTH could not be attributed to the significant decrease in PM_(2.5)(from-5.08 to-6.32μg/(m3·year))and CO(from-0.053 to-0.090 mg/(m^(3)·year))because their decreasing rates were approximately the same in all the cities.The relatively stable O_(3)concentrations during the investigating period in BJ may be attributed to a faster decreasing rate of NO_(2)(BJ:-2.55μg/(m^(3)·year);TJ:-1.16μg/(m^(3)·year);HB:-1.34μg/(m3·year)),indicating that the continued reduction of NOx will be an effective mitigation strategy for reducing regional O_(3)pollution.Significant positive correlations were found between daily maximum8 hr average(MDA8)O_(3)concentrations and vehicle population and highway freight transportation in HB.Therefore,we speculate that the increase in rural NO_(x)emissions due to the increase in vehicle emissions in the vast rural areas around HB greatly accelerates regional O_(3)formation,accounting for the significant increasing trends of O_(3)in HB.

关键词： Tropospheric ozone The Beijing-Tianjin-Hebei region Spatio-temporal trends Rural vehicle emission

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Evaluation of offline sampling for atmospheric C3-C11 non-methane hydrocarbons

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Journal of Environmental Sciences 2022年第3期34卷 132-140页

作者： Zhiguo liu Chengtang Liu Zhouming He Yujing Mu Chenglong Zhang Yuanyuan Zhang Pengfei liu Yuzheng Wang Junfeng liu Research Center for Eco-Environmental Sciences Chinese Academy of SciencesBeijing 100085China Center for Excellence in Urban Atmospheric Environment Institute of Regional EnvironmentChinese Academy of SciencesXiamen 361021China University of Chinese Academy of Sciences Beijing 100049China Clear Science&Technology Co. LtdBeijing 100029China

The concentration variation of C3-C11 non-methane hydrocarbons(NMHCs)collected in several types of commercial flexible bags and adsorption tubes was systematically inves-tigated using a gas chromatography-flame ionization detector(GC-FID)system.The per-centage loss of each NMHC in the polyvinyl fluoride(PVF)bags was less than 5%during a 7-hr storage period;significant NMHCs loss was detected in aluminum foil composite film and fluorinated ethylene propylene bags.The thermal desorption efficiency of NMHCs for adsorption tubes filled Carbopack B and Carboxen1000 sorbents was greater than 95%at 300℃,and the loss of NMHCs in the adsorption tubes during 20-days storage at 4℃was less than 8%.The thermal desorption efficiency for C11 NMHCs in the adsorption tube filled with Carbograph 1 and Carbosieve SⅢabsorbents was less than 40%at 300℃,and pyrolysis of the absorbents at 330℃interfered significantly with the measurements of some alkenes.The loss of alkenes was significant when NMHCs were sampled by cryo-enrichment at-90℃in the presence of O3 for the online NMHC measurements,and negligible for enrichment us-ing adsorption tubes at 25℃.Although O_(3)scrubbers have been widely used to eliminate the influence of O_(3)on NMHC measurements,the loss of NMHCs with carbon numbers greater than 8 was more than 10%.Therefore,PVF bags and adsorption tubes filled Carbopack B and Carboxen1000 sorbents were recommended for the sampling of atmospheric NMHCs.

关键词： Non-methane hydrocarbons(NMHCs) Gas chromatography-flame ionization detector(GC-FID) Offline sampling Adsorption tubes Ozone scrubber

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Characteristics and sources of peroxyacetyl nitrate(PAN)in the rural North China Plain:Results from1-year continuous observations

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Journal of Environmental Sciences 2024年第4期138卷 719-731页

作者： Xin liu Xiaowei He Chenglong Zhang Yifei Song Shuyang Xie Chengtang Liu Pengfei liu Yuanyuan Zhang Yujing Mu Junfeng liu Research Center for Eco-Environmental Sciences Chinese Academy of SciencesBeijing 100085China University of Chinese Academy of Sciences Beijing 100049China

Peroxyacetyl nitrate(PAN)is an important photochemical pollutant in the troposphere,whereas long-term measurements are scarce in rural areas in North China Plain(NCP),resulting in unclear seasonal variations and sources of PAN in rural NCP.In this study,we conducted a 1-year observation of PAN during 2021-2022 at the rural NCP site.The average concentrations of PAN were 1.10,0.75,0.65,and 0.88 ppbv in spring,summer,autumn,and winter,respectively,with a 1-year average of 0.81±0.60 ppbv.Calculations indicate that the loss of PAN through thermal decomposition in summer accounts for 43.2% of the total formed PAN,which is an important reason for the low concentration of PAN in summer.We speculate that since the correlation between PAN and O_(3) in winter is significantly lower than that in other seasons,the observed regional transport of PAN cannot be ignored in winter.Through budget analysis,regional transport accounted for 12.8% and 55.9% of the observed PAN on the spring and winter pollution days,respectively,which showed that regional transport played key roles during the photochemical pollution of the rural NCP in winter.The potential source contribution function revealed that the transported PAN mainly comes from southern Hebei in spring.In winter,the transported PAN was mainly from Langfang,Hengshui,and southern Beijing.Our findings may aid in understanding PAN variations in different seasons in rural areas and highlight the impact of regional transport on the PAN budget.

关键词： Photochemical pollution Peroxyacetyl nitrate(PAN) Seasonal variations Regional transport Rural area

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Photochemical production of carbonyl sulfide,carbon disulfide and dimethyl sulfide in a lake water

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Journal of Environmental Sciences 2017年第1期29卷 146-156页

作者： Qianqian Du Yujing Mu Chenglong Zhang Junfeng liu Yuanyuan Zhang Chengtang Liu Research Center for Eco-Environmental Sciences Chinese Academy of SciencesBeijing 100085China Center for Excellence in Urban Atmospheric Environment Institute of Urban EnvironmentChinese Academy of SciencesXiamen 361021China University of Chinese Academy of Sciences Beijing 100049China

Photochemical production of carbonyl sulfide（COS）,carbon disulfide（CS_2） and dimethyl sulfide（DMS） was intensively studied in the water from the Aohai Lake of Beijing city.The lake water was found to be highly supersaturated with COS,CS_2 and DMS,with their initial concentrations of 0.91 ± 0.073 nmol/L,0.55 ± 0.071 nmol/L and 0.37 ± 0.062 nmol/L,respectively.The evident photochemical production of COS and CS_2 in the lake water under irradiation of 365 nm and 302 nm indicated that photochemical production of them might be the reason for their supersaturation.The similar dependence of wavelength and oxygen for photochemical production of COS,CS_2 and DMS implied that they might be from the same precursors.The water cage effect was found to favor COS production but inhibit CS_2and DMS formation,indicating that COS photochemical production was mainly from direct degradation of the precursors and the formation of CS_2 and DMS needed intermediates via combination of carbon-centered radicals and sulfur-centered radicals.The above assumptions were further confirmed by simulation experiments with addition of carbonyls and amino acids（cysteine and methionine）,and the photochemical formation mechanisms for COS,CS_2 and DMS in water were derived from the investigations.

关键词： Photochemical production Carbonyl sulfide Carbon disulfide Dimethyl sulfide Water

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Characteristics and influence factors of NO2 exchange flux between the atmosphere and P. nigra

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Journal of Environmental Sciences 2019年第10期31卷 155-165页

作者： Chun Chen Yuzheng Wang Yuanyuan Zhang Chengtang Liu Xiaoxiu Lun Yujing Mu Chenglong Zhang Junfeng liu Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Beijing 100085 China University of Chinese Academy of Sciences Beijing 100049 China Center for Excellence in Urban Atmospheric Environment Institute of Urban Environment Chinese Academy of Sciences Xiamen 361021China College of Environmental Science & Engineering Beijing Forest University Beijing 100083 China

Nitrogen dioxide(NO2)is an important substance in atmospheric photochemical processes and can also be absorbed by plants.N02 fluxes between the atmosphere and P.nigrc seedlings were investigated by a double dynamic chambers method in Beijing from June 15to September 3,2017.The range of N02 exchange fluxes between P.nigra seedlings and the atmosphere was from-14.6 to 0.8 nmol/(m2.sec)(the positive data represent N02 emissior from trees,while the negative values indicate absorption).Under ambient concentrations the mean NO2 flux during the fast-growing stage(Jun.15-Aug.4)was-3.0 nmol/(m2·sec)greater than the flux of-1.5 nmol/(m2-sec)during the later growth stage(Aug.8-Sept.3)The daily exchange fluxes of NO2 obviously fluctuated.The fluxes were largest in the morning and decreased gradually over time.Additionally,the N02 fluxes were larger undei high light intensities than under low light intensities during the whole growth period.The effects of temperature on N02 fluxes were different under two growth periods.The NO2exchange fluxes were larger in a range of temperatures close to 44℃in the fast-growing stage,whereas there were no evident differences in N02 exchange fluxes under widel differing temperatures in the later growth stage.Under polluted conditions,the uptake ability of N02 was weakened.Additionally,the compensation point of N02 was 5.6 ppb ir the fast-growing stage,whereas it was 1.4 ppb in the later growth stage.The depositior velocities of NO2 were between 0.3 and 2.4 mm/sec.

关键词： Nitrogen dioxide Exchange flux P.nigra Compensation point

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Serious BTEX pollution in rural area of the North China Plain during winter season

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Journal of Environmental Sciences 2015年第4期27卷 186-190页

作者： Kankan liu Chenglong Zhang Ye Cheng Chengtang Liu Hongxing Zhang Gen Zhang Xu Sun Yujing Mu Research Center for Eco-Environmental Sciences Chinese Academy of Sciences

Atmospheric BTEX compounds（benzene, toluene, ethylbenzene and xylenes） in a rural site of the North China Plain（NCP） were preliminarily investigated in winter, and the outdoor concentrations（25.8–236.0 μg/m^3） were found to be much higher than those reported in urban regions. The pollution of BTEX inside a farmer＇s house was even more serious, with combined concentrations of 254.5–1552.9 μg/m^3. Based on the ratio of benzene to toluene（1.17 ± 0.34） measured, the serious BTEX pollution in the rural site was mainly ascribed to domestic coal combustion for heating during the winter season. With the enhancement of farmers＇ incomes in recent years, coal consumption by farmers in the NCP is rapidly increasing to keep their houses warm, and hence the serious air pollution in rural areas of the NCP during winter, including BTEX, should be paid great attention.

关键词： BTEX Rural area Coal combustion

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Activity maintenance of the excised branches and a case study of NO_2 exchange between the atmosphere and P.nigra branches

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Journal of Environmental Sciences 2019年第6期31卷 316-326页

作者： Chun Chen Yuzheng Wang Yuanyuan Zhang Xiaoxiu Lun Chengtang Liu Yujing Mu Chenglong Zhang Pengfei liu Chaoyang Xue Min Song Can Ye Junfeng liu Research Center for Eco-Environmental Sciences Chinese Academy of Sciences University of Chinese Academy of Sciences Center for Excellence in Urban Atmospheric Environment Institute of Urban Environment Chinese Academy of Sciences College of Environmental Science & Engineering Beijing Forest University

The efficient maintenance of the activity of excised branches is the powerful guarantee to accurately determine gas exchange flux between the detached branches of tall trees and the atmosphere. In this study, the net photosynthetic rate(NPR) of the excised branches and branches in situ were measured simultaneously by using two photosynthetic instruments to characterize the activity of the excised branches of Phyllostachys nigra. The ratio of normalized NPR of excised branches to NPR in situ was used to assess the photosynthetic activity of detached branches. Based on photosynthetic activity, an optimal hydroponics protocol for maintaining activity of excised P. nigra branches was presented:1/8 times the concentration of Gamborg B5 vitamin mixture with p H = 6. Under the best cultivation protocol, photosynthetic activity of excised P. nigra branches could be maintained more than 90% within 6 hr in the light intensity range of 200–2000 μmol/(m2·sec) and temperature range of 13.4–28.7°C. The nitrogen dioxide(NO2) flux differences between in situ and in vitro branches and the atmosphere were compared using double dynamic chambers.Based on the maintenance method of excised branches, the NO2 exchange flux between the excised P. nigra branches and the atmosphere(from-1.01 to-2.72 nmol/(m2·sec) was basically consistent with between the branches in situ and the atmosphere(from-1.12 to-3.16 nmol/(m2 sec)) within 6 hr. Therefore, this study provided a feasible protocol for in vitro measurement of gas exchange between tall trees and the atmosphere for a period of time.

关键词： Excised branches Activity maintenance NO2 exchange flux Hydroponics Dynamic chamber

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The levels, sources and reactivity of volatile organic compounds in a typical urban area of Northeast China

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Journal of Environmental Sciences 2019年第5期31卷 121-134页

作者： Zhuobiao Ma Chengtang Liu Chenglong Zhang Pengfei liu Can Ye Chaoyang Xue Di Zhao Jichen Sun Yiming Du Fahe Chai Yujing Mu Research Center for Eco-Environmental Sciences Chinese Academy of Sciences University of Chinese Academy of Sciences Center for Excellence in Regional Atmospheric Environment Institute of Urban Environment Chinese Academy of Sciences Shenyang Academy of Environmental Sciences Shenyang Environmental Monitoring Centre Chinese Research Academy of Environmental Sciences

Air concentrations of volatile organic compounds(VOCs) were continually measured at a monitoring site in Shenyang from 20 August to 16 September 2017. The average concentrations of alkanes, alkenes, aromatics and carbonyls were 28.54, 6.30, 5.59 and9.78 ppbv, respectively. Seven sources were identified by the Positive Matrix Factorization model based on the measurement data of VOCs and CO. Vehicle exhaust contributed the most(36.15%) to the total propene-equivalent concentration of the measured VOCs,followed by combustion emission(16.92%), vegetation emission and secondary formation(14.33%), solvent usage(10.59%), petrochemical industry emission(9.89%), petrol evaporation(6.28%), and liquefied petroleum gas(LPG) usage(5.84%). Vehicle exhaust, solvent usage and combustion emission were found to be the top three VOC sources for O_3 formation potential, accounting for 34.52%, 16.55% and 11.94%, respectively. The diurnal variation of the total VOCs from each source could be well explained by their emission characteristics,e.g., the two peaks of VOC concentrations from LPG usage were in line with the cooking times for breakfast and lunch. Wind rose plots of the VOCs from each source could reveal the possible distribution of the sources around the monitoring site. The O_3 pollution episodes during the measurement period were found to be coincident with the elevation of VOCs, which was mainly due to the air parcel from the southeast direction where petrochemical industry emission was found to be dominant, suggesting that the petrochemical industry emission from the southeast was probably a significant cause of O_3 pollution in Shenyang.

关键词： Volatile organic compounds Source apportionment Photochemical ozone formation Field measurement

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Pollution levels, composition characteristics and sources of atmospheric PM2.5 in a rural area of the North China Plain during winter

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Journal of Environmental Sciences 2020年第9期32卷 172-182页

作者： Xiaoxi Zhao Xiujuan Zhao Pengfei liu Can Ye Chaoyang Xue Chenglong Zhang Yuanyuan Zhang Chengtang Liu Junfeng liu Hui Chen Jianmin Chen Yujing Mu Research Center for Eco-Environmental Sciences Chinese Academy of SciencesBeijing 100085China Institute of Urban Meteorology Chinese Meteorological AdministrationBeijing 100089China Center for Excellence in Urban Atmospheric Environment Institute of Urban EnvironmentChinese Academy of SciencesXiamen 361021China University of Chinese Academy of Sciences Beijing 100049China Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention Department of Environmental Science and EngineeringFudan UniversityShanghai 200433China Key Laboratory of Atmospheric Chemistry China Meteorological AdministrationBeijing 100081China

The pollution levels,composition characteristics and sources of atmospheric PM2.5 were investigated based on field measurement at a rural site in the North China Plain(NCP) from pre-heating period to heating period in winter of 2017.The hourly average concentrations of PM2.5 frequently exceeded 150 μg/m3 and even achieved 400 μg/m3,indicating that the PM2.5pollution was still very serious despite the implementation of stricter control measures in the rural area.Compared with the pre-heating period,the mean concentrations of organic carbon(OG),element carbon(EC) and chlorine ion(Cl-) during the heating period increased by 20.8%,36.6% and 38.8%,accompanying with increments of their proportions in PM2.5from 37.5%,9.8% and 5.5% to 42.9%,12.7% and 7.2%,respectively.The significant increase of both their concentrations and proportions during the heating period was mainly ascribed to the residential coal combustion.The proportions of sulfate,nitrate and ammonium respectively increased from 9.9%,10.9% and 9.0% in nighttime to 13.8%,16.2% and 11.1% in daytime,implying that the daytime photochemical reactions made remarkable contributions to the secondary inorganic aerosols.The simulation results from WRF-Chem revealed that the emission of residential coal combustion in the rural area was underestimated by the current emission inventory.Six sources identified by positive matrix factorization(PMF) based on the measurement were residential coal combustion,secondary formation of inorganic aerosols,biomass burning,vehicle emission and raising dust,contributing to atmospheric PM2.5 of 40.5%,21.2%,16.4%,10.8%,8.6% and 2.5%,respectively.

关键词： pollution winter characteristics

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基于网格化管理的氯碱化工企业安全管理模式构建研究

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山东化工 2022年第5期51卷 206-208页

作者：王爱刘呈堂滨化集团股份有限公司山东滨州256600 山东京卫制药有限公司山东泰安271000

基于氯碱化工企业的发展历程和背景,统计分析近几年氯碱行业发生的安全事故,采用AHP层次分析法对某氯碱企业生产单元风险辨识分析,得到安全事故中占据重要影响程度的事故致灾因子,为氯碱化工企业的安全管理提供管理方向和重点,同时也为... 详细信息

基于氯碱化工企业的发展历程和背景,统计分析近几年氯碱行业发生的安全事故,采用AHP层次分析法对某氯碱企业生产单元风险辨识分析,得到安全事故中占据重要影响程度的事故致灾因子,为氯碱化工企业的安全管理提供管理方向和重点,同时也为企业的网格化管理的划分以及企业的精准化管理提供理论性的文献资料基础。基于网格化安全管理模式对氯碱企业进行网格化划分和对应的网格化安全管理团队的建立,网格化的构建和有效地实施提供精准化的管理,提升企业的安全管理水平和企业安全文化。

关键词：氯碱化工安全管理构建模式网格化安全培训精准化标准化风险辨识

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