Changes of Labile Organic Carbon Fractions in Soils Under Different Rotation Systems

Soil labile (biologically active) organic carbon fractions under different crop rotation systems in Jiangsu Province, China, were investigated after 10 years of rotation. The rotation systems, including green manurerice-rice (GmRR), wheat-rice-rice (WRR), wheat-rice (WR) and wheat/corn intercrop-rice (WCR) rotations,were established on paddy soils using a randomized complete block design with three replicates. The total organic carbon (TOC), total nitrogen (TN) and water-soluble organic carbon (WSOC) in the soils under different systems were greater in the GmRR and WRR than in the WR and WCR rotation systems because the soils under triple cropping often received more crop residues than the soils under double cropping. Both the WSOC and the microbial biomass carbon (MBC) contents in the soils of the GmRR rotation system were significantly greater than those in the other crop rotation systems, which was due to the return of green manure to the fields of the GmRR rotation system. The results of a 13C nuclear magnetic resonance (13C-NMR) analysis indicated that the structural characteristics of soil WSOC were similar under the four crop rotation systems with carbohydrates and long-chain aliphatics being the major components. Correlation analysis showed that the content of the WSOC was positively correlated with that of the MBC (P ＜0.01),and all had significantly positive correlations with TOC and TN. The coefficients of variation (CVs) for WSOC and WSOC/TOC were greater than the other indices (e.g, MBC, TOC and TN), suggesting that WSOC in the soils was more sensitive to these rotation systems. The results above indicated that the soil amended with green manure could not only increase the usable C source for soil microorganisms, but could also enhance soil organic matter content; hence, rotation with green manure would be a good strategy for sustainable agriculture.

基于3DEEM-PARAFAC方法对不同秸秆还田方式下WSOC的组分与荧光特征分析

以三维荧光光谱结合平行因子法(3DEEM-PARAFAC)为主要分析方法,分析秸秆未还田条件下3种耕作方法(免耕、浅翻、深翻)及相应还田方法(秸秆免耕覆盖、浅翻还田、深翻还田)下,土壤水溶性有机碳(WSOC)的组分及不同土层的荧光特性。结果表明,土壤WSOC解析出4个荧光组分,分别为2个类腐殖质物质C1(310,240/410 nm)、C2(270/465 nm)和两个类蛋白物质C3(280,230/340 nm)、C4(220/300 nm);秸秆深翻还田在>35 cm土层有不同程度的促进类腐殖华物质C1、C2组分向类蛋白物质C4组分转化的趋势;土壤WSOC的来源均为植物源与微生物源的混合贡献,深翻还田在>35 cm土层腐殖化程度最低。秸秆还田与深翻对深层土壤WSOC中结构较为复杂、芳香性高的有机物的矿化分解有一定促进作用。

Emission of organic carbon, elemental carbon and water-soluble ions from crop straw burning under flaming and smoldering conditions

Emissions from major agricultural residues were measured using a self-designed combustion system. Emission factors （EFs） of organic carbon （OC）, elemental carbon （EC）, and water-soluble ions （WSIs） （K＋, NH4＋, Na＋, Mg2＋, Ca2＋, Cl-, NO3-, SO42–） in smoke from wheat and rice straw were measured under flaming and smoldering conditions. The OC1/TC （total carbon） was highest （45.8% flaming, 57.7% smoldering） among carbon fractions. The mean EFs for OC （EFOC） and EC （EFEC） were 9.2 ± 3.9 and 2.2 ± 0.7 g/kg for wheat straw and 6.4 ± 1.9 and 1.1 ± 0.3 g/kg for rice straw under flaming conditions, while they were 40.8 ± 5.6 and 5.8 ± 1.0 g/kg and 37.6 ± 6.3 and 5.0 ± 1.4 g/kg under smoldering conditions, respectively. Higher EC ratios were observed in particulate matter （PM） mass under flaming conditions. The OC and EC for the two combustion patterns were significantly correlated （p 〈 0.01, R = 0.95 for wheat straw; p 〈 0.01, R = 0.97 for rice straw）, and a higher positive correlation between OC3 and EC was observed under both combustion conditions. WSIs emitted from flaming smoke were dominated by Cl- and K＋, which contributed 3.4% and 2.4% of the PM mass for rice straw and 2.2% and 1.0% for wheat straw, respectively. The EFs of Cl- and K＋ were 0.73 ± 0.16 and 0.51 ± 0.14 g/kg for wheat straw and 0.25 ± 0.15 and 0.12 ± 0.05 g/kg for rice straw under flaming conditions, while they were 0.42 ± 0.28 and 0.12 ± 0.06 g/kg and 0.30 ± 0.27 and 0.05 ± 0.03 g/kg under smoldering conditions, respectively. Na＋, Mg2＋, and NH4＋ were vital components in PM, comprising from 0.8% （smoldering） to 3.1% （flaming） of the mass. Strong correlations of Cl- with K＋, NH4＋, and Na＋ ions were observed in rice straw and the calculated diagnostic ratios of OC/EC, K＋/Na＋ and Cl-/Na＋ could be useful to distinguishing crop straw burning from other sources of atmospheric pollution.

Insights into reactive oxygen species formation induced by water-soluble organic compounds and transition metals using spectroscopic method

Ambient particulate matter(PM)can cause adverse health effects via their ability to produce Reactive Oxygen Species(ROS).Water-Soluble Organic Compounds(WSOCs),a complex mixture of organic compounds which usually coexist with Transition Metals(TMs)in PM,have been found to contribute to ROS formation.However,the interaction between WSOCs and TMs and its effect on ROS generation are still unknown.In this study,we examined the ROS concentrations of V,Zn,Suwannee River Fulvic Acid(SRFA),Suwannee River Humic Acid(SRHA)and the mixtures of V/Zn and SRFA/SRHA by using a cell-free 2’,7’-Dichlorodihydrofluorescein(DCFH)assay.The results showed that V or Zn synergistically promoted ROS generated by SRFA,but had an antagonistic effect on ROS generated by SRHA.Fluorescence quenching experiments indicated that V and Zn were more prone to form stable complexes with aromatic humic acid-like component(C1)and fulvic acidlike component(C3)in SRFA and SRHA.Results suggested that the underlying mechanism involving the fulvic acid-like component in SRFA more tending to complex with TMs to facilitate ROS generation throughπelectron transfer.Our work showed that the complexing ability and complexing stability of atmospheric PM organics with metals could significantly affect ROS generation.It is recommended that the research deploying multiple analytical methods to quantify the impact of PM components on public health and environment is needed in the future.

Soil Organic Carbon Transformation and Related Properties in Urban Soil Under Impervious Surfaces

Installation of impervious surface in urban area prevents the exchange of material and energy between soil and other environmental counterparts,thereby resulting in negative effects on soil function and urban environment.Soil samples were collected at 0-20cm depth in Nanjing City,China,in which seven sites were selected for urban open soils,and fourteen sites with similar parent material were selected for the impervious-covered soils,to examine the effect of impervious surface on soil properties and microbial activities,and to determine the most important soil properties associated with soil organic carbon(SOC)transformation in the urban soils covered by impervious surfaces.Soil organic carbon and water-soluble organic carbon(WSOC)concentrations,potential carbon(C)and nitrogen(N)mineralization rates,basal respiration,and physicochemical properties with respect to C transformation were measured.Installation of impervious surface severely affected soil physicochemical properties and microbial activities,e.g.,it significantly decreased total N contents,potential C mineralization and basal respiration rate(P<0.01),while increased pH,clay and Olsen-P concentrations.Soil organic carbon in the sealed soils at 0-20 cm was 2.35 kg m^(-2),which was significantly lower than the value of 4.52 kg m^(-2)in the open soils(P<0.05).Canonical correlation analysis showed WSOC played a major role in determining SOC transformation in the impervious-covered soil,and it was highly correlated with total N content and potential C mineralization rate.These findings demonstrate that installation of impervious surface in urban area,which will result in decreases of SOC and total N concentrations and soil microbial activities,has certain negative consequences for soil fertility and long-term storage of SOC.

Effect of Vegetation Succession on Organic Carbon,Carbon of Humus Acids and Dissolved Organic Carbon in Soils of Copper Mine Tailings Sites

Carbon of humus acids(HSAC) and dissolved organic carbon(DOC) are the most active forms of soil organic carbon(SOC) and play an important role in global carbon recycling. We investigated the concentrations of HSAC,water-soluble organic carbon(WSOC),hot water-extractable organic carbon(HWOC) and SOC in soils under different vegetation types of four copper mine tailings sites with differing vegetation succession time periods in Tongling,China. The concentrations of HSAC,WSOC,HWOC and SOC increased with vegetation succession. WSOC concentration increased with the accumulation of SOC in the tailings,and a linearly positive correlation existed between the concentrations of HSAC and SOC in the tailings. However,the percentages of HSAC and DOC in the SOC decreased during vegetation succession. The rate of SOC accumulation was higher when the succession time was longer than 20 years,whereas the speeds of soil organic matter(SOM) decomposition and humification were slow,and the concentrations of HSAC and DOC increased slowly in the tailings. The percentage of carbon of humic acid(HAC) in HSAC increased with vegetation succession,and the values of humification index(HI),HAC/carbon of fulvic acid,also increased with the accumulation of HSAC and SOC in soils of the tailings sites. However,the HI value in the each of the tailings was less than 0.50. The humification rate of SOM was lower than the accumulation rate of SOM,and the level of soil fertility was still very low in the tailings even after 40 years of natural restoration.

施肥对毛竹林土壤水溶性有机碳氮与温室气体排放的影响

森林生态系统作为生物圈的重要组成部分,维持着全球植被碳库的86%和土壤碳库的40%（Houghton et al.,2001;胡会峰等,2006）。因此,森林在调节全球气候、维持全球碳平衡方面起着非常重要的作用（Fang et al.,2001;Woodbury et al.,2007;Hu et al.,2008）。然而,

不同有机物料还田对黑土活性有机碳组分含量的影响

采用小区试验,研究大豆-玉米轮作模式下不同有机物料还田处理对黑土土壤活性有机碳及其组分变化特征的影响。结果表明:不同有机物料还田处理显著提高土壤总有机碳含量,与单施化肥(NPK)相比,配施有机肥(MNPK)、化肥配施生物炭(BNPK)、秸秆全量还田(SNPK)分别增加3.04%、2.44%、1.66%;不同有机物料还田措施下土壤水溶性有机碳含量分别增加46.28%、7.57%、14.18%;配施有机肥(MNPK)对土壤易氧化有机碳含量起显著的促进作用,秸秆还田(SNPK)和配施生物炭(BNPK)分别增加土壤微生物量碳17.20%和14.23%。配施有机肥能提高水溶性有机碳比例和土壤微生物量碳比例。土壤活性有机碳各组分之间存在显著相关性。有机肥与化肥的配施(MNPK)对于增加土壤活性有机碳含量和有效调控其关键组分具有重要作用。

生草提高山核桃林土壤有机碳含量及微生物功能多样性

山核桃（Carya cathayensis）是中国特有的高档干果和木本油料树种,但高强度经营导致林地土壤性质的改变,为了解生草对土壤的修复效果,在山核桃主产区设置了紫云英（Astragalus sinicus）、油菜（Brassica campestris）、黑麦草（Lolium perenne）和免耕4种处理,对土壤有机碳及微生物功能多样性进行分析。结果表明,不同生草栽培后,山核桃林地土壤总有机碳（total organic carbon,TOC）质量分数显著增加,与免耕相比,种植油菜、黑麦草、紫云英4 a后土壤TOC分别提高了23.12%,26.61%和24.74%,增加的组分以羰基碳为主,但并未改变土壤碳库的稳定性;同时也显著提高了林地土壤微生物量碳（microbial biomass carbon,MBC）和水溶性有机碳（water-soluble organic carbon,WSOC）的质量分数,MBC增加了138.61%~159.68,WSOC提高了56.24%~69.47%%。3种生草的土壤微生物活性（average well color development,AWCD）显著高于免耕,微生物多样性指数（Shannon index,H）和均匀度指数（evenness index,E）则表现为油菜、紫云英处理显著高于免耕。研究表明,生草栽培能有效提高林地土壤TOC质量分数和微生物功能多样性,为山核桃林地土壤修复和科学管理提供参考。

坡耕地黑土活性有机碳空间分布及生物有效性

以一东北黑土区典型漫岗坡耕地为研究对象，测定不同侵蚀程度地形部位的活性碳组分，以分析土壤侵蚀对活性碳组分的影响以及沉积区侵蚀碳的归宿。研究结果表明：各地形部位表层黑土（0～20cm）水溶性有机碳（WSOC）含量介于14．6～20．0mg／kg之间，低于总SOC含量的0．15％WSOC在沿坡迁移的同时，向下淋溶也很显著。MBC含量为121．5～583．6mg／kg，占总SOC的1．0%～4．7％。Min—C变化范围为52．8～115．3mg／kg，土壤Min-C差异主要集中在表层。土壤侵蚀显著降低侵蚀部位表层土壤Min-C、WSOC和MBC含量，沉积区土壤MBC、Min—C含量及其商值较高，而WSOC却无显著累积。相关关系表明，表层土壤Min—C、WSOC和MBC均于总SOC含量呈显著正相关。初步的研究结果认为侵蚀物质的输入增加沉积区表层土壤微生物活性和土壤碳的矿化潜力，常年处于氧化环境中的侵蚀碳可能被矿化而难以累积。

施肥对板栗林土壤活性碳库和温室气体排放的影响

在浙江省临安市典型板栗林试验地,利用静态箱-气相色谱法测定了不同施肥条件下板栗林土壤CO2和N2O排放速率,同时测定了土壤水溶性有机碳(WSOC)和微生物量碳(MBC)含量。初步探讨了施肥对板栗林土壤活性碳库与温室气体排放速率的影响,以及土壤温室气体排放速率与活性碳库之间的关系。本试验设置不施肥(CK)、无机肥(IF)、有机肥(OF)和有机无机混合肥(OIF,1/2无机肥和1/2有机肥)4个施肥处理。结果表明,施肥1个月后,与不施肥(CK)处理相比,无机肥(IF)、有机肥(OF)和有机无机混合肥(OIF)处理下土壤CO2排放速率分别增加了87%、38%和61%,N2O排放速率分别增加了101%、67%和95%;而施肥6个月后,与CK处理相比,IF、OF和OIF处理下土壤CO2排放速率分别增加了51%、43%和64%,N2O排放速率分别增加了21%、29%和47%。同时,施肥显著增加板栗林土壤WSOC和MBC含量(P<0.05)。此外,土壤CO2和N2O排放速率与WSOC含量均呈显著正相关(P<0.05),而与MBC含量没有显著的相关性。因此,施肥引起板栗林地土壤WSOC含量增加可能是导致板栗林地土壤温室气体排放增加的重要原因之一。

玉米秸秆还田对土壤有机碳、微生物功能多样性及甘蓝产量的影响

在甘蓝蔬菜地采用随机区组设计,共设4个秸秆还田试验处理,即JG1(低用量,秸秆7 500 kg·hm^(-2)),JG2(中用量,秸秆11 250 kg·hm^(-2)),JG3(高用量,秸秆22 500 kg·hm^(-2))和CK(秸秆不还田),采集分析不同处理土壤有机碳及微生物功能多样性。结果表明:秸秆还田后显著提高土壤微生物量碳(MBC)和水溶性有机碳(WSOC)含量,MBC增加了127.0%~147.7%,WSOC提高了54.1%~69.4%。中、高用量玉米秸秆还田后,土壤微生物活性(AWCD)、微生物Shannon指数(H)和均匀度指数(E)均显著高于对照,甘蓝产量分别提高16.6%和11.1%。研究结果表明,秸秆还田是一种有效提高土壤有机碳及微生物功能多样性的土壤管理方法。

武夷山不同海拔土壤水溶性有机碳的含量特征

土壤水溶性有机碳（WSOC）是土壤碳循环中最活跃的组成部分之一。采用TOC—VCPN总有机碳仪测定了武夷山4个典型海拔地的植被土壤水溶性有机碳的含量，分析了土壤水溶性有机碳与土壤因子的关系。结果表明：不同林分间土壤水溶性有机碳含量随海拔上升而增加，随土层深度的增加而减少；土壤水溶性有机碳含量占总有机碳的比值介于0．02％～0．16％，以高山草甸10～25cm土层最高，常绿阔叶林25～40cm土层最低；不同海拔梯度的土壤水溶性有机碳与总有机碳、微生物量碳、土壤湿度、全氮存在显著线性正相关，与土壤温度、pH之间无相关性。

施肥对板栗林地土壤N_2O通量动态变化的影响

2011年6月—2012年6月期间,在浙江省临安市典型板栗林地进行施肥对土壤N2O通量变化影响的试验研究。目的在于探明不同施肥处理下板栗林地土壤N2O通量的动态变化规律,并探讨土壤N2O通量和土壤环境因子之间的关系。试验设置4个处理:对照(不施肥)、无机肥、有机肥、有机无机混合肥。采用静态箱-气相色谱法测定了板栗林地土壤N2O通量,并测定了土壤温度、水分、水溶性有机碳(WSOC)和微生物量碳(MBC)含量。结果表明:板栗林土壤N2O通量呈显著季节性变化,最大值出现在夏季,最小值出现在冬季;而且,施肥处理显著提高土壤N2O年均通量和年累积量;在整个试验期间,无机肥、有机肥和有机无机混合肥处理下土壤N2O的排放系数分别达到0.96%、1.45%和1.29%。此外,施肥也显著增加了土壤WSOC和MBC的含量(P<0.05)。不同施肥处理条件下,土壤N2O通量与土壤5 cm处温度、WSOC含量间均呈极显著正相关(P<0.01),但与MBC含量之间的相关性不显著。土壤N2O排放与土壤含水量间除对照处理外均没有显著相关性。综上所述,施肥引起土壤WSOC含量的增加可能是施肥增加板栗林地土壤N2O排放速率的主要原因之一。

茶园与相邻林地土壤有机碳及基础呼吸的垂直分布特征

对茶园及相邻林地土壤基础呼吸的垂直分布特征进行了研究,并试图寻求其与土壤有机碳(SOC)、水溶性有机碳(WSOC)、微生物生物量碳(MBC)的关系。结果表明茶园和林地土壤有机碳、土壤呼吸积累量、水溶性有机碳和微生物生物量碳均随着土壤深度的增加而减少,且茶园均值大于林地。在0~100 cm土壤层次内,茶园土壤质量敏感性指标(WSOC/SOC)平均值、代谢熵(q CO2)平均值均大于林地,微生物熵(q MBC)平均值小于林地。茶园和林地土壤基础呼吸速率与SOC、WSOC及MBC呈显著正相关,向后筛选回归模型表明对茶园土壤基础呼吸的影响作用依次为SOC>MBC>WSOC,对林地土壤基础呼吸的影响作用则为WSOC>SOC>MBC。茶园土壤代谢作用强于林地,但茶园有机碳库的稳定性比林地差,不利于土壤有机碳库的积累,为促进茶叶生产的持续健康发展,茶园土壤需要更加科学合理的施肥和耕作措施。

不同施肥雷竹林土壤水溶性有机碳动态变化

为了解目前生产上不同施肥习惯对土壤活性有机碳产生的影响,从2002年8月至2003年4月动态采集了各施肥处理土壤样品,用岛津TOC-VcPH有机碳分析仪测定了土壤水溶性有机碳含量。结果表明:不同施肥处理土壤水溶性有机碳含量均表现出8、10月最高,12月开始降低,次年2月降至低谷,而4月又上升的变化规律。试验全过程中,3个有机无机肥混合施用处理土壤水溶性有机碳含量始终高于3个单施化肥处理,并且差异达显著水平,并随着有机肥用量的增加,土壤水溶性有机碳含量也显著增加。所有施肥处理土壤水溶性有机碳含量均是覆盖区高于未覆盖区,覆盖区平均是未覆盖区的1.56倍。土壤水溶性有机碳含量与土壤总有机碳含量存在极显著相关性,与土壤水解氮相关性也达显著水平。

施肥对板栗林土壤CH_4吸收通量动态的影响

为了探明无机肥和有机肥施用对板栗林地土壤CH4吸收通量动态的影响,探讨板栗林地土壤CH4通量与环境因子之间的关系,在浙江省临安市典型板栗林样地布置施肥试验。于2011年6月2012年6月期间,采用静态箱-气相色谱法测定了不施肥(CK)、无机肥(IF)、有机肥(OF)和有机无机混合肥(OIF)处理下土壤CH4吸收通量的全年动态变化,并测定了土壤温度、土壤水分、水溶性有机碳(WSOC)和微生物量碳(MBC)含量。结果表明,板栗林土壤CH4吸收通量呈现明显的季节性变化,最大值出现在9月,最小值出现在2 3月;施肥处理均显著抑制了土壤CH4的吸收,具体表现为IF、OF和OIF处理下土壤CH4年吸收量与CK处理[CH43.09 kg/(hm2·a)]相比分别减少了7.0%、1.6%和4.4%。此外,施肥显著增加了土壤WSOC和MBC含量(P<0.05),且施肥使土壤碱解氮、铵态氮、硝态氮、全氮和有机质含量均有不同程度的增加。相关性分析表明,土壤CH4吸收通量与土壤表层5 cm处温度之间呈显著正相关(P<0.05),但与土壤水分、MBC含量之间没有显著相关性;土壤CH4吸收与土壤WSOC含量之间(除CK处理外)均具有显著相关性(P<0.05)。因此,施肥引起土壤理化性质[如NH+4-N、NO-3-N、全氮(TN)、有机碳(SOC)等]和WSOC含量的改变可能是施肥显著抑制了板栗林土壤CH4排放的主要原因。

不同林分下土壤活性有机碳库研究

采样分析常绿阔叶林、马尾松林和人工杉木林不同层次土壤的活性有机碳含量。结果表明 :常绿阔叶林土壤微生物量碳和易氧化态碳含量高于马尾松与杉木林土壤 ,杉木林土壤水溶性碳含量相对较低。从不同层次看 ,土壤微生物量碳、易氧化态碳含量均随着土层深度加深而递减。水溶性碳、微生物量碳和易氧化态碳占总有机碳的比率分别波动在 0 31%～ 1 18%、0 90 %～ 2 5 1%和 7 0 3%～ 2 9 5 2 %之间 ,其中 ,土壤水溶性碳占总有机碳比率为马尾松林 >常绿阔叶林 >人工杉木林 ,易氧化态碳占总有机碳比率常绿阔叶林明显高于马尾松林和杉木林。不同土壤水溶性有机碳占总有机碳比率随剖面从上到下均表明出上升趋势 ,而易氧化态碳占总有机碳比率随剖面加深有规律地下降。土壤有机碳总量与各活性碳之间以及各类活性碳之间相关性均达到极显著水平。

基于离子配对法的黄山地区云凝结核闭合研究

为了对黄山地区云凝结核(Cloud Condensation Nuclei,CCN)进行闭合研究,2014年6月30日至7月28日在黄山光明顶对大气气溶胶理化性质和CCN数浓度进行观测,分析了气溶胶化学组分、谱分布以及CCN数浓度随时间变化的特征,通过κ-Kohler理论并使用离子配对法计算得到CCN数浓度与观测得到的CCN数浓度进行对比。结果表明:计算与观测的CCN闭合结果较好,低过饱和度CCN闭合结果好于高过饱和度,过饱和度较低时低估了CCN数浓度,而过饱和度较高时则高估了CCN数浓度,由此说明气溶胶的化学组分数据对预测CCN数浓度至关重要,同时说明该方法可以实现CCN的闭合。考虑到40%水溶性有机碳(Water Soluble Organic Carbon,WSOC)对气溶胶粒子吸湿性影响,在较低过饱和度CCN闭合结果较好,但影响效果并不显著,尤其是在拟合结果相对较差的高过饱和度下基本没有影响。因此,气溶胶粒子中水溶性无机组分对CCN活化有重要影响,而含量较多、化学组分复杂并且吸湿性不确定的WSOC对CCN活化影响较为有限,这与一些研究得出无机组分对于气溶胶吸湿性的影响比具有复杂特征的有机组分更重要的结论相符合。

上海市淀山湖区域灰霾天大气颗粒物中碳组分的污染特征

采集了上海市淀山湖区域 2015 年 3 月至 2016 年 2 月灰霾天大气颗粒物中 PM2.5 样品,重点分析了其中碳组分的污染特征。结果表明,PM2.5年均质量浓度为(69.01±37.05)μg/m3,数值与有机碳(OC)、元素碳(EC)和水溶性有机碳(WSOC)显著相关,相关性大小与灰霾程度有关。OC、EC的年均质量浓度分别为(4.46±3.41)μg/m3和(2.15±1.31)μg/m3,呈现冬季高、夏季低的趋势,两者显著相关,相关性大小同样与灰霾程度有关。WSOC 的年均质量浓度为(2.07±1.40)μg/m3,春季高于冬季,且灰霾天质量浓度大于非灰霾天相应值。碳组分对大气能见度的影响较大,需得到控制。