Variation characteristics

变化特征
  • 文章类型: Journal Article
    目标:以TP53变异为特征的MDS和AML总体预后不良。然而,具体来说,在TP53变体和VAF不同的患者中也观察到了预后的差异.方法:这里,我们回顾性分析了MDS患者的数据集,MPN,和AML患者在2018年2月至2023年12月期间接受了靶向DNA测序,并筛选了可报告TP53变异的患者.收集人口统计数据和临床数据,使用cBioPortal和Kaplan-MeierPlotter数据库分析TP53改变与患者预后(AML/MDS)之间的关系.使用本研究的数据分析了TP53变异的VAF与预后之间的关系。结果:在58例患者中发现了62种TP53变体。我们主要鉴定了单个突变(79.31%,46/58),其次是两倍(17.24%,10/58)和三倍(3.45%,2/58)突变。变异主要富集在TP53的exon4-exon8中。Missense(72.58%,45/62)突变是变异的主要类型,其次是剪接位点(9.68%,6/62),胡说八道(9.68%,6/62),移码(6.45%,4/62),和indel(1.61%,1/62)突变。在这项研究中,p.Arg175His和p.Arg273His是高频率TP53突变,DNMT3A和TET2是三种髓系肿瘤中常见的共突变基因;然而,我们报道了一些在MPN中尚未在公共数据库中发现的新TP53变体.此外,以TP53改变为特征的MDS或AML的OS比未改变组的患者短(P<0.01),低TP53mRNA水平与AML患者OS较短相关(P<0.01)。我们中心的数据进一步发现,在MDS患者中,较高的VAF(≥10%)与较短的OS相关(中位数为2.75vs.24个月)(P<0.01)。结论:TP53突变主要富集在exon4-exon8,是髓系肿瘤的错义突变和单突变,并与MDS/AML的不良预后相关,在MDS患者中,TP53突变的较高VAF(≥10%)与较短的OS相关。
    Objectives: MDS and AML characterized by TP53 variations have a poor prognosis in general. However, specifically, differences in prognosis have also been observed in patients with different TP53 variants and VAFs.Methods: Here, we retrospectively analyzed datasets of patients with MDS, MPN, and AML who underwent targeted DNA sequencing from February 2018 to December 2023, and patients with reportable TP53 variations were screened. Demographic data and clinical data were collected, and the relationship between TP53 alterations and patient prognosis (AML/MDS) was analyzed using the cBioPortal and Kaplan-Meier Plotter databases. The relationship between the VAFs of TP53 variations and prognoses was analyzed using data from the present study.Results: Sixty-two variants of TP53 were identified in 58 patients. We mainly identified single mutations (79.31%, 46/58), followed by double (17.24%, 10/58) and triple (3.45%, 2/58) mutations. The variations were mainly enriched in exon4-exon8 of TP53. Missense (72.58%, 45/62) mutations were the main type of variations, followed by splice-site (9.68%, 6/62), nonsense (9.68%, 6/62), frameshift (6.45%, 4/62), and indel (1.61%, 1/62) mutations. In this study, p.Arg175His and p.Arg273His were high-frequency TP53 mutations, and DNMT3A and TET2 were commonly co-mutated genes in the three types of myeloid neoplasms; However, we reported some new TP53 variants in MPN that have not been found in the public database. Moreover, MDS or AML characterized by altered TP53 had a shorter OS than patients in the unaltered group (P<0.01), low TP53 mRNA levels were associated with shorter OS in patients with AML (P<0.01). Data from our center further found higher VAF (≥10%) associated with shorter OS in patients with MDS (median 2.75 vs. 24 months) (P<0.01).Conclusion: TP53 mutations are mainly enriched in exon4-exon8, are missense and single mutations in myeloid neoplasms, and are associated with poor prognosis of MDS/AML, and higher VAF (≥10%) of TP53 mutations associated with a shorter OS in patients with MDS.
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  • 文章类型: Journal Article
    茎含水量是反映植物活力并维持其内部水平衡的关键参数。鉴于对越冬期不同阶段茎部含水量特征及其影响因素的认识不足,这项研究的重点是宏碁truncumBunge,并开发了基于物联网(IoT)的生态信息监测系统。该系统包含一个专有的茎含水量传感器,允许非侵入性,在监测各种环境参数的同时,原位和实时采集茎含水量。我们详细阐明了茎含水量的变化特征及其对各种环境因素的响应。结果表明:(1)越冬期间,茎含水量在三个阶段表现出“白天上升和夜间下降”的昼夜变化,在茎含水量达到极值和每日波动范围的时刻表现出差异。茎水含量在落叶和芽破裂阶段表现出最小的波动,但在休眠阶段经历了显着的冻融交替,导致每日波动范围增加。(2)环境参数与茎含水量之间的皮尔逊相关系数随阶段动态变化。路径分析显示,在落叶阶段,茎温度和饱和蒸汽压亏缺是影响茎含水量的主要因素;在休眠期,气温和饱和蒸汽压不足直接影响茎含水量;在破芽阶段,影响茎含水量的主要参数是饱和蒸汽压亏缺和茎温度。该研究为揭示越冬期间树茎组织内的水运输模式及其环境适应机制提供了有价值的见解,协助科学制定冬季管理策略,保护树木免受严寒和冻害,同时促进下一年的健康成长。
    Stem water content serves as a pivotal parameter that reflects the plant vitality and maintains their internal water balance. Given the insufficient comprehension regarding the stem water content characteristics and its influencing factors during different stages of the overwintering period, the study focused on Acer truncatum Bunge and developed an Internet of Things (IoT)-based ecological information monitoring system. The system incorporated a proprietary stem water content sensor, allowing non-invasive, in-situ and real time acquisition of stem water content while monitoring diverse environmental parameters. We conducted a detailed elucidation of stem water content variation characteristics and their responses to diverse environmental factors. The results showed: (1) During the overwintering period, stem water content exhibited diurnal variations characterized by \" daytime ascent and nighttime descent\" across the three stages, exhibiting differences in the moment when the stem water content reaches extremal values and daily fluctuations ranges. Stem water content exhibited minimal fluctuations during deciduous and bud-breaking stages but experienced significant freezing-thawing alternations during the dormant stage, leading to an increased daily fluctuation range. (2) The Pearson correlation coefficients between environmental parameters and stem water content varied dynamically across stages. Path analysis revealed that during the deciduous stage, stem temperature and saturation vapor pressure deficit were dominant factors influencing stem water content; during dormant stage, air temperature and saturation vapor pressure deficit directly impacted stem water content; during the bud-breaking stage, the primary parameters affecting stem water content were saturation vapor pressure deficit and stem temperature. The study provides valuable insights into unveiling the water transport patterns within tree stems tissue and their environmental adaptation mechanisms during the overwintering period, aiding in the scientific development of winter management strategies to protect trees from severe cold and freezing damage, while fostering healthy growth in the subsequent year.
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  • 文章类型: English Abstract
    探讨北京某城区大气细颗粒物(PM2.5)中水溶性离子的含量及变化特征,提出污染防治方案。水溶性离子,气态前体(SO2,NO2),和气象因素(温度,对2022年PM2.5的RH)进行了分析测定。结果表明,北京市城区PM2.5中水溶性离子含量最高的是NO3-,NH4+,和SO42-,占PM2.5的52.7%。PM2.5和SNA的质量浓度低于历史结果,而SNA的比例,SOR,NOR高于历史结果。这表明北京市细颗粒物污染状况有了明显改善,但仍具有较强的二次污染特征。NO3-/SO42-(2.2)高于历史及附近省市,反映了移动源不断扩大的影响力。从季节变化来看,PM2.5呈现秋高夏低的特征。秋季NO3-的比例最高,spring,和冬季;夏季SO42-的比例最高;NH4的比例在每个季节变化不大。NOR和SOR的季节变化规律几乎相反,这反映了NOR和SOR之间转换因子的差异。北京市区SNA的主要形态为NH4NO3和(NH4)2SO4。冬季阳离子和阴离子的中和度最高,夏季,阳离子NH4+略有不足,春季和秋季NH4过量。北京城区是一个富含氨的环境。就污染程度而言,RH,颗粒物水分,和水溶性离子质量浓度都随着污染水平的增加而增加,SNA增长最快,其在PM2.5中的比例先增加后稳定,其他水溶性离子的贡献率逐渐降低。在空间分布方面,SNA在中心城区和郊区的质量浓度关系为NO3->SO42->NH4+,反映了以NO3-为主的污染特征。SNA对PM2.5的贡献率最高的是东部地区,中心城区,和传输点,表明中心城区和东部地区的二级反应相对活跃,区域运输也是二次离子的重要来源。
    To explore the content and variation characteristics of water-soluble ions of atmospheric fine particles (PM2.5) in a Beijing urban area and put forward the pollution prevention and control scheme, the water-soluble ions, gaseous precursors (SO2, NO2), and meteorological factors (temperature, RH) of PM2.5 in 2022 were analyzed and determined. The results showed that the water-soluble ions with the highest proportion in PM2.5 in the Beijing City urban area were NO3-, NH4+, and SO42-, accounting for 52.7% of PM2.5. The mass concentrations of PM2.5 and SNA were lower than the historical results, whereas the proportion of SNA, SOR, and NOR was higher than the historical results. This showed that the fine particulate matter pollution in Beijing has been significantly improved, but it still has strong secondary pollution characteristics. NO3-/SO42-(2.2) was higher than those of historical and nearby provinces and cities, reflecting the expanding influence of mobile sources. In terms of seasonal variation, PM2.5 showed the characteristic of high in autumn and low in summer. The proportion of NO3- was the highest in autumn, spring, and winter; the proportion of SO42- was the highest in summer; and the proportion of NH4+ changed little in each season. The seasonal variation rules of NOR and SOR were almost opposite, which reflected the difference in transformation factors between NOR and SOR. The main forms of SNA in the Beijing urban area were NH4NO3 and (NH4)2SO4. The neutralization degree of cations and anions was the highest in winter, the cation NH4+ was slightly insufficient in summer, and NH4+ was in excess in spring and autumn. The Beijing urban area was an ammonia-rich environment. In terms of pollution level, RH, particulate matter moisture, and water-soluble ions mass concentration all increased with the increase in pollution level, and SNA increased fastest, with its proportion in PM2.5 increasing first and then stabilizing, whereas the contribution rate of other water-soluble ions decreased gradually. In terms of spatial distribution, the mass concentration relationship of SNA at the central urban area and suburbs was NO3- > SO42- > NH4+, which reflected the pollution characteristics dominated by NO3-. The highest contribution rate of SNA to PM2.5 occurred in the eastern region, the central urban area, and the transmission point, indicating that the secondary reaction was relatively active in the central urban area and the eastern region, and the regional transport was also an important source of secondary ions.
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  • 文章类型: Journal Article
    高速公路建设对发展中国家的生态环境造成了重大威胁,因此,发展中国家高速公路沿线生态恢复力的变化特征具有重要意义。这项实证研究的重点是柬埔寨金边-西哈努克高速公路2公里范围内的典型区域,并利用遥感和地理信息系统(GIS)技术分析了高速公路沿线生态恢复力的变化特征。研究结果表明,由于高速公路的建设,转入或移出土地利用类型的土地利用类型增加,此外,土地利用类型呈现出自然属性减少和人类属性增加的趋势。发现高速公路建设对土地利用类型重心的转移速率有观察到的影响,重心向高速公路建设方向转移。植被覆盖度较高的西部地区建设对生态恢复力的影响高于城市化程度较高的东部地区。研究建立了基于土地利用类型的高速公路沿线生态恢复力变化特征的理论评价模型,高速公路建设的可持续性,维护区域生态环境。
    Expressway construction has caused a significant threat to the ecological environment in developing countries, and therefore the variation characteristics of ecological resilience along the expressway in developing countries are of major importance. This empirical study focuses on a typical area within a 2-km range of the Phnom Penh-Sihanoukville Expressway in Cambodia and uses remote sensing and geographic information systems (GIS) technology to analyze the variation characteristics of ecological resilience along the expressway. The results of the study reveal that due to the construction of expressways, the land use types transferred into or out of the land use types increase and furthermore the land use types show a trend of decreasing natural attributes and increasing human attributes. It is found that expressway construction has an observed effect on the transfer rate of the center of gravity of land use type, and the direction of the center of gravity shifts in the direction of expressway construction. The impact of construction on the ecological resilience of the western region with higher vegetation coverage was higher than that of the eastern region with higher urbanization. The research develops a theoretical evaluation model based on land use type of the variation characteristics of ecological resilience along the expressway, which can be used to enable the sustainability of expressway construction and maintain the regional ecological environment.
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  • 文章类型: Journal Article
    细颗粒物(PM2.5)污染给人类健康和社会发展带来极大的负面影响。从异质性和国家和城市相结合的角度分析,本研究旨在探讨PM2.5污染的变化规律及其影响因素,使用2015年至2019年中国273个城市的地理和时间加权回归(GTWR)。建立了全面的分析框架,由14个多维度的决定因素组成,包括人口,经济发展,技术,和自然条件。结果表明:(1)PM2.5污染在冬季最严重,在夏季最不严重。而每月,daily,每小时的变化显示为“U”形,脉冲形和“W”形模式;(2)中国东南部沿海城市的空气质量优于其他城市,决定因素之间的相互作用增强了PM2.5污染的空间不平衡;(3)决定因素对PM2.5污染特异性表现出显著的异质性,人口密度,贸易开放,第二产业,和发明专利对华北平原的PM2.5污染表现出最强烈的积极影响。相对湿度,在PM2.5污染严重的城市,降水量和人均GDP对改善大气质量更为有效。海拔高度和建成区的比例在中国西部表现出强烈的影响。这些发现将有助于为区域空气污染控制制定有针对性和差异化的预防策略。
    Fine particulate matter (PM2.5) pollution brings great negative impacts to human health and social development. From the perspective of heterogeneity and the combination of national and urban analysis, this study aims to investigate the variation patterns of PM2.5 pollution and its determinants, using geographically and temporally weighted regression (GTWR) in 273 Chinese cities from 2015 to 2019. A comprehensive analytical framework was established, composed of 14 determinants from multi-dimensions, including population, economic development, technology, and natural conditions. The results indicated that: (1) PM2.5 pollution was most severe in winter and the least severe in summer, while the monthly, daily, and hourly variations showed \"U\"-shaped, pulse-shaped and \"W\"-shaped patterns; (2) Coastal cities in southeast China have better air quality than other cities, and the interaction between determinants enhanced the spatial disequilibrium of PM2.5 pollution; (3) The determinants showed significant heterogeneity on PM2.5 pollution-specifically, population density, trade openness, the secondary industry, and invention patents exhibited the strongest positive impacts on PM2.5 pollution in the North China Plain. Relative humidity, precipitation and per capita GDP were more effective in improving atmospheric quality in cities with serious PM2.5 pollution. Altitude and the proportion of built-up areas showed strong effects in western China. These findings will be conductive to formulating targeted and differentiated prevention strategies for regional air pollution control.
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  • 文章类型: English Abstract
    Understanding the responses of functional trait variation for grassland plants to grazing disturbance is highly helpful to clarify the community assembly mechanism, functional diversity maintenance, plant adaptation and their strategies. We investigated plant functional traits (plant height, root length, leaf area, root area, leaf dry matter content, shoot dry matter content, root dry matter content, specific leaf area, specific root length and root/ shoot ratio) and the responses of their variation characteristics to grazing disturbance in enclosure and grazing grasslands in Horqin Sandy Land. The results showed that the interspecific variation of functional trait was obviously higher than the intraspecific variation in degraded grassland. The relative contribution of interspecific variation to the overall trait variation ranged from 70.2% to 95.1%, while that of intraspecific variation only contributed 4.9% to 29.8%. However, that did not imply the intraspecific variation could be ignored in the community assembly. The interspecific variation in grazing grassland was lower than that in enclosed grassland, while the intraspecific variation increased but the interspecific variation decreased in grazing grassland. Grazing resulted in the decrease of leaf area and leaf dry matter content but the increase of specific root length for pastoral-resistant grasses. However, pastoral-tolerant forbs would improve their dominance in the community by decreasing specific root length and increa-sing leaf area and leaf dry matter content. The traits sensitive to grazing were leaf area, leaf dry matter content, specific root length, and specific leaf area. Leaf traits and root traits were significantly positively correlated within and with each other. Grazing would enhance the synergy of root traits while reduce the synergy of leaf traits. That meant grazing could change the trade-off strategy of functional traits in individual and population levels, and thus affect vegetation structure and function in community level.
    研究草地植物功能性状变异对放牧干扰的响应机制,有助于解析草地生态系统群落构建和功能多样性维持机制及植物对环境的适应及权衡策略。以科尔沁沙地退化草地为对象,研究围封和放牧草地物种多种功能性状(植株高度、根系长度、叶面积、根面积、叶片干物质含量、地上干物质含量、根系干物质含量、比叶面积、比根长和根冠比)变异特征及其对放牧干扰的响应机制。结果表明: 退化草地物种种间性状变异明显高于种内变异,种间性状变异对总体变异的贡献率占比高达70.2%~95.1%,而种内变异仅为4.9%~29.8%,但群落构建中物种的种内变异仍不可忽视。放牧草地物种种间性状变异低于围封草地,且放牧草地种内变异增加而种间变异减小。放牧导致不耐牧的优良禾本科牧草叶面积和叶片干物质含量下降而比根长增加,但耐牧的杂类草则通过增加叶面积和叶片干物质含量并降低比根长来提高在群落中的优势地位。退化草地对放牧响应较为敏感的功能性状有叶面积、叶片干物质含量、比根长和比叶面积。植物叶片性状和根系性状自身及彼此间均呈显著正相关,但放牧会增强根系性状的协同效应而减弱叶片性状的协同效应。说明放牧会驱动植物个体和种群功能性状权衡策略发生改变,进而起到调控植物群落结构和功能的作用。.
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  • 文章类型: Journal Article
    有机硝酸盐,在次级有机气溶胶和细颗粒的主要成分中,在区域氮循环中发挥重要作用,臭氧预算,和云凝结核形成。然而,山区颗粒有机硝酸盐的污染特征和人为污染物迁移的影响仍然知之甚少。在这项研究中,冬季和春季在华北平原的高海拔山区进行了现场采样和测量。采用超高效液相色谱-电喷雾质谱法测定细颗粒中5种颗粒有机硝酸盐的含量。冬季和春季颗粒有机硝酸盐的平均总浓度为330±121ngm-3和247±63ngm-3。单萜衍生的有机硝酸盐是两个季节的主要成分,其贡献高于70%,冬季和春季有机气溶胶分别占1.2±0.8%和2.0±1.0%,分别。冬季的有机硝酸盐含量明显高于春季,这归因于山谷微风和煤燃烧羽流的强烈影响。白天山谷微风带来的NOx和颗粒物浓度的增加促进了MHN215,OAKN359和OAHN361的形成,而SO2丰度的增加和由高排放源运输的硫酸盐气溶胶在夜间影响了MDCN247的形成。
    Particulate organic nitrates, among the major components of secondary organic aerosols and fine particles, play important roles in regional nitrogen cycle, ozone budget, and cloud condensation nuclei formation. However, the pollution characteristics of particulate organic nitrates at mountain areas and the effects of anthropogenic pollutant transport remain poorly understood. In this study, field sampling and measurements were conducted at a high-elevation mountain site over North China Plain in winter and spring. Total five kinds of particulate organic nitrates in fine particles were determined by ultra-high performance liquid chromatography-electrospray mass spectrometry. The average total concentrations of particulate organic nitrates were 330 ± 121 ng m-3 and 247 ± 63 ng m-3 in winter and spring. The monoterpene-derived organic nitrates were the dominant components in both seasons with their contribution higher than 70%, accounting for 1.2 ± 0.8% and 2.0 ± 1.0% in organic aerosols in winter and spring, respectively. The significantly higher levels of particulate organic nitrates in winter than spring was ascribed to the strong effects of mountain-valley breezes and coal combustion plumes. The increasing concentrations of NOx and particulate matters brought by the valley breeze at daytime facilitated the formation of MHN215, OAKN359, and OAHN361, while the rising SO2 abundance and the sulfate aerosols transported by elevated emission sources affected the formation of MDCN247 at nighttime.
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  • 文章类型: Journal Article
    A rapid reaction occurs near the exhaust nozzle when vehicle emissions contact the air. Twenty diesel vehicles were studied using a new multipoint sampling system that is suitable for studying the exhaust plume near the exhaust nozzle. The variation characteristics of fine particle matter (PM2.5) and its components in diesel vehicle exhaust plumes were analyzed. The PM2.5 emissions gradually increased with increasing distance from the nozzle in the plume. Elemental carbon emissions remained basically unchanged, organic carbon and total carbon (TC) increased with increasing distance. The concentrations of SO42-, NO3- and NH4+ (SNA) directly emitted by the vehicles were very low but increased rapidly in the exhaust plume. The selective catalytic reduction (SCR) reduced 42.7% TC, 40% NO3- emissions, but increased 104% SO42- and 36% NH4+ emissions, respectively. In summary, the SCR reduced 29% primary PM2.5 emissions for the tested diesel vehicles. The NH4NO3 particle formation maybe more important in the plume, and there maybe other forms of formation of NH4+ (eg. NH4Cl). The generation of secondary organic carbon (SOC) plays a leading role in the generation of secondary PM2.5. The SCR enhanced the formation of SOC and SNA in the plume, but comprehensive analysis shows that the SCR more enhanced the SNA formation in the plume, which is mainly new particles formation process. The inconsistency between secondary organic aerosol (SOA) and primary organic aerosol definitions is one of the important reasons for the difference between SOA simulation and observation.
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  • 文章类型: Journal Article
    Emergency response mechanisms were activated throughout China during the COVID-19 outbreak. It is different from the temporary, partial, and limited pollution control measures taken to ensure the regional environmental quality during several important events such as the 2008 Beijing Olympic Games and the 2014 Asia-Pacific Economic Cooperation (APEC). During the COVID-19 epidemic period, extensive movement of people and almost all unnecessary industrial production (necessary industrial production refers to the production of food, epidemic prevention materials, etc.) have been severely restricted, so transportation and industrial production have been greatly reduced. This is a rare extreme emission reduction scenario that presents a unique opportunity for atmospheric research. In this study, based on hourly mass concentration data of NO2 and SO2 from atmospheric monitoring sites in the Beijing-Tianjin-Hebei (BTH) region during the COVID-19 epidemic period, the changes in transportation and industrial production in the region, data statistics, and spatial analysis were used to analyze the pollution changes and their causes. The results indicate that the NO2 and SO2 concentrations in the BTH region decreased significantly during the epidemic period. The spatial distribution pattern of NO2 pollution in the BTH region was \"high in the southeast and low in the northwest,\" and SO2 pollution in the BTH region was high in the southern and eastern parts of Hebei. The initiation of emergency response level 1 had an obvious effect on reducing NO2 and SO2 pollution in the region, while the impact of emergency response level 2 and below was limited. Compared with the single traffic control, the comprehensive control, similar to the emergency response, had a better effect on reducing NO2 pollution in the region. The control of major large cities in the region also had a certain effect on alleviating NO2 and SO2 pollution in the entire region. Moreover, for activities under short-term control, it is particularly important to guard against the \"retaliatory growth\" after the control is lifted. By reducing and controlling some polluting industries in industrial production, the degree of NO2 and SO2 pollution in the region can be effectively reduced. The manufacturing industry of chemical raw materials and the chemical products and non-metallic mineral products industry made a great contribution to the change in industrial source pollution emissions in the BTH region during the COVID-19 epidemic. Road traffic emissions remained an important source of NO2 emissions in the BTH region during this period. NO2 emission reduction can be effectively achieved by controlling road traffic and transportation.
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  • 文章类型: English Abstract
    Black carbon (BC) was measured at Chengdu from December 1, 2017, to November 30, 2018, using a seven-channel aethalometer (AE-33). The variation characteristics of BC were obtained. BC sources were explored based on the aethalometer model and a hybrid single particle Lagrangian integrated trajectory model (Hysplit-4). The results showed the BC concentration was the highest in the winter (8.18 μg·m-3) with the monthly mean of 11.11 μg·m-3 peaking in December, followed by the spring (5.11 μg·m-3) and autumn (3.91 μg·m-3), and was the lowest in summer (3.28 μg·m-3) with the lowest monthly mean of 2.30 μg·m-3 in July. The annual average concentration of BC was 5.26 μg·m-3 with a standard deviation of 4.27 μg·m-3. The diurnal variations of BC showed typical bimodal patterns in four seasons mainly due to the influence of the boundary layer and traffic rush. The source apportionment of BC showed that the liquid fuel (e.g., vehicle emission) had higher contribution to total BC concentration during all seasons (ranging from 69% in winter to 82% in summer) than solid fuel (e.g., coal and biomass combustion). The contribution of liquid fuel to the total BC was higher in summer, while solid fuel had a higher contribution in winter. The diurnal cycles of BC source apportionment demonstrated that the contribution of liquid fuel increased in the rush hours. The results of potential source contribution function and concentration weighted trajectory showed that the potential sources of BC in Chengdu were slightly different in different seasons and were mainly affected by the different air mass sources. However, the main potential source regions were the surrounding areas of Chengdu and the areas between Chengdu and Chongqing (the Chuanyu City group). The mass contribution to the BC in Chengdu was high in the region where liquid fuel most affected the total BC. Additionally, the southern part of Shaanxi and the southern part of Gansu were also potential sources of BC, and in Summer, some regions in Guangxi and Guizhou could become the source regions of BC in Chengdu.
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