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1.
Biogenic Volatile Organic Compounds (VOC): An Overview on Emission, Physiology and Ecology 总被引：50，自引：0，他引：50
This overview compiles the actual knowledge of the biogenic emissions of some volatile organic compounds (VOCs), i.e., isoprene, terpenes, alkanes, alkenes, alcohols, esters, carbonyls, and acids. We discuss VOC biosynthesis, emission inventories, relations between emission and plant physiology as well as temperature and radiation, and ecophysiological functions. For isoprene and monoterpenes, an extended summary of standard emission factors, with data related to the plant genus and species, is included. The data compilation shows that we have quite a substantial knowledge of the emission of isoprene and monoterpenes, including emission rates, emission regulation, and biosynthesis. The situation is worse in the case of numerous other compounds (other VOCs or OVOCs) being emitted by the biosphere. This is reflected in the insufficient knowledge of emission rates and biological functions. Except for the terpenoids, only a limited number of studies of OVOCs are available; data are summarized for alkanes, alkenes, carbonyls, alcohols, acids, and esters. In addition to closing these gaps of knowledge, one of the major objectives for future VOC research is improving our knowledge of the fate of organic carbon in the atmosphere, ending up in oxidation products and/or as aerosol particles. 相似文献
2.
Information from a variety of sources, including an airborne field expedition in November 1985, is used to produce estimates of the annual emissions of some hydrocarbons from bushfires, and isoprene from trees, in tropical Australia. For the continent north of 23° S the annual bushfires (biomass burning) input was estimated, in units of Tg carbon, to be 2 TgC (uncertainty range 0.8–5 TgC), emitted predominantly during the May to October dryseason. Isoprene emissions during this period were estimated also to be 2 TgC (uncertainty range 0.5–8 TgC), but were estimated to be an order of magnitude higher during the November to April wet season, at a level of 23 TgC (uncertainty range 6–100 TgC).The large annual emission of isoprene over the tropical part of the Australian continent yields ppbv levels of isoprene measured at the surface in summertime. Isoprene reactivity with hydroxyl radical is such that at these concentrations isoprene must be a dominant factor in controlling the concentration of OH radical in the convective boundary layer. Simple arguments based on the convective velocity scale suggest that the shape of the isoprene vertical profile in November 1985 would be consistent with available data on the OH-isoprene reaction rate if OH concentration in the boundary layer averaged about 2.5×106 cm-3 over the middle part of the day.Temporarily at the International Meteorological Institute, Stockholm University, S-106 91, Stockholm, Sweden. 相似文献
3.
J. D. Fuentes D. Wang H. H. Neumann T. J. Gillespie G. Den Hartog T. F. Dann 《Journal of Atmospheric Chemistry》1996,25(1):67-95
Experiments were conducted during the growing season of 1993 at a mixed deciduous forest in southern Ontario, Canada to investigate the atmospheric abundance of hydrocarbons from phytogenic origins, and to measure emission rates from foliage of deciduous trees. The most abundant phytogenic chemical species found in the ambient air were isoprene and the monoterpenes -pinene and -pinene. Prior to leaf-bud break during spring, ambient hydrocarbon mixing ratios above the forest remained barely above instrument detection limit (20 parts per trillion), but they became abundant during the latter part of the growing season. Peak isoprene mixing ratios reached nearly 10 parts per billion (ppbv) during mid-growing season while maximum monoterpene mixing ratios were close to 2 ppbv. Both isoprene and monoterpene mixing ratios exhibited marked diurnal variations. Typical isoprene mixing ratios were highest during mid-afternoon and were lowest during nighttime. Peak isoprene mixing ratios coincided with maximum canopy temperature. The diurnal pattern of ambient isoprene mixing ratio was closely linked to the local emissions from foliage. Isoprene emission rates from foliage were measured by enclosing branches of trees inside environment-controlled cuvette systems and measuring the gas mixing ratio difference between cuvette inlet and outlet airstream. Isoprene emissions depended on tree species, foliage ontogeny, and environmental factors such as foliage temperature and intercepted photosynthetically active radiation (PAR). For instance, young (<1 month old) aspen leaves released approximately 80 times less isoprene than mature (>3 months old) leaves. During the latter part of the growing season the amount of carbon released back to the atmosphere as isoprene by big-tooth and trembling aspen leaves accounted for approximately 2% of the photosynthetically fixed carbon. Significant isoprene mixing ratio gradients existed between the forest crown and at twice canopy height above the ground. The gradient diffusion approach coupled with similarity theory was used to estimate canopy isoprene flux densities. These canopy fluxes compared favorably with values obtained from a multilayered canopy model that utilized locally measured plant microclimate, biomass distribution and leaf isoprene emission rate data. Modeled isoprene fluxes were approximately 30% higher compared to measured fluxes. Further comparisons between measured and modeled canopy biogenic hydrocarbon flux densities are required to assess uncertainties in modeling systems that provide inventories of biogenic hydrocarbons. 相似文献
4.
5.
This assessment of the atmospheric methane budget for the African Continent is based on a set of experimental data obtained in tropical Africa including methane emission from various biogenic sources, and biomass burning, and methane consumption in savanna and forest soils. Emission rates from the various sources, uptake rates of soils, and complementary data from the litterature allow calculation of regional methane fluxes by means of different data bases. Biomass burning, animals and natural wetlands are the three dominant sources of methane in Africa while rice paddy fields and termites appear as minor sources. The total methane emission is estimated to be in the range 20–40 MT of CH4 per year, methane uptake by soils being less than 2 MT per year. Net methane emission from the African continent accounts for less than 10% of global emissions from terrestrial ecosystems. 相似文献
6.
中国大陆黑碳气溶胶排放清单 总被引：1，自引：0，他引：1
The detailed high-resolution emission inventory of black carbon (BC) from China in the year 2000 was calculated. The latest fuel consumption data including fossil and biomass fuels, and socio-economic statistics used were obtained from government agencies, mostly at the county level, and some new emission factors (Efs) from local measurements were also used. National and regional summaries of emissions were presented at 0.2°×0.2°resolution. Total BC emission was 1499.4 Gg in 2000, mainly due to the burning of coal and biomass. The BC emission estimated here is higher than those in previous studies, mainly because the emissions from coal burning by rural industries and residences were previously underestimated. More BC aerosols were emitted from eastern China than western China. A strong seasonal dependence was observed for BC emissions, with peaks in January and December and low emissions in July and August; and this seasonality is mainly due to patterns in residential heating and the open burning of crop residues. 相似文献
7.
C. Holzke T. Dindorf J. Kesselmeier U. Kuhn R. Koppmann 《Journal of Atmospheric Chemistry》2006,55(1):81-102
The source strength of volatile organic compounds (VOCs) emitted by vegetation is of great interest for the understanding of processes in atmospheric chemistry and climate change. In this study terpene emissions from branches of European beech (Fagus sylvatica L.) were studied in a deciduous forest. Using the branch enclosure technique changes in the emission pattern and the variation of emission rates over the year were investigated over two consecutive vegetation periods. More than 10 monoterpene compounds were found in the emissions, among which sabinene dominates. For most compounds the emission pattern changed only slightly over the year. Interestingly, two compounds tentatively identified as para-cymene and cis-ocimene showed differences in the emission behaviour in late summer compared to the other terpenes. In contrast to previous studies our investigation characterise European beech as a strong emitter. For the main compounds the emission rates changed up to two orders of magnitude as a function of temperature and light over the day. In general, highest emission rates were observed in summer and lowest in fall. A seasonality was characterized by a temperature independent decline of emissions in late summer, resulting in changes of the standard emission rate on the order of one magnitude. A standard emission factor of up to 3.5 nmol m−2s−1 for the sum of measured terpenes was calculated. No emissions were found in early spring even though leaves were fully developed and temperature and light conditions were moderate. The results underline the importance of characterising the annual variation of the emission behaviour. Especially for the up-scaling to global VOC emissions, seasonal influences have to be considered to achieve realistic emission inventories. 相似文献
8.
Leesun Kim Ian E. Galbally Nichola Porter Ian A Weeks Sarah J Lawson 《Journal of Atmospheric Chemistry》2011,68(3):265-279
Emissions of biogenic volatile organic compounds (BVOCs) from mechanical wounding of leaves and branches of plants can contribute
to the atmospheric burden of volatile organic compounds (VOCs) in both (a) urban airsheds (from urban garden maintenance)
and (b) the global atmosphere (from large scale forest harvesting). These emissions of BVOCs are poorly understood and quantified,
and their role in urban and global emissions inventories neglected. This paper presents measurements of the magnitude, duration
and composition of emissions of BVOCs, carbon dioxide (CO2) and methane (CH4) from freshly cut leaf mulch and wood chips derived from a common eucalypt tree, Eucalyptus sideroxylon (red ironbark), found in southeastern Australian forests and gardens. The emissions of BVOCs from freshly cut and shredded
leaves and wood of E. sideroxylon were found to be 2.3 ± 0.6 and 0.05 ± 0.04 mg g-1 DM (Dry Mass) from leaf mulch and wood chips respectively and to last typically for 1 day following cutting. Three sampling
techniques were used for VOC speciation and the 12 most abundant BVOCs released from the mulch materials were identified.
The specific BVOCs emitted in order of decreasing abundance from leaf mulch are: (a) stored plant oils, 1,8-cineole, α–pinene
and o-cymene which make up the major part of the emissions, (b) a minor contribution from chemicals associated with environmental
stress and wound defence, (Z)–3–hexenyl acetate, (E)-2-hexenal and (Z)-3-hexen-1-ol, and (c) a second minor contribution from
metabolic products, acetaldehyde and acetone. The observed integrated emissions of BVOCs from leaves following mulching are
equivalent to more than half and perhaps all of the likely stored plant oils in the leaves. For the two comparable studies
available, one of a plant with stored oils (this study) and one of a plant without stored plant oils, the emissions of leaf
wound defence BVOCs are in the same range for both plants. In the plant with stored plant oils, the plant oil emissions are
about a factor of 11 larger in emission rate than the plant wound defence BVOCs. A compilation of available leaf wounding
BVOC emission studies indicates that for plants with stored plant oils, plant oil emissions dominate, whereas with other plants,
leaf wound defence BVOCs dominate the emissions. 相似文献
9.
10.
Biogenic emissions from Pinus halepensis: a typical species of the Mediterranean area 总被引：2，自引：0，他引：2
Volatile organic compounds (VOCs) emissions by vegetation present in the Mediterranean area are not well known. They may contribute with anthropogenic VOC emissions to the tropospheric ozone formation that reaches important level in the European Mediterranean region. The present work, carried out as part of the European ESCOMPTE project «fiEld experimentS to COnstrain Models of atmospheric Pollution and Transport of Emissions», adds a new contribution to the inventory of the main natural hydrocarbons sources likely to participate in the ozone production. The corresponding measurement campaign was conducted in La Barben, a site close to Marseilles (France), with the aim to quantify the terpenic emission pattern and the behaviour of Pinus halepensis, an important Mediterranean species slightly studied.The determination of biogenic emissions from P. halepensis was done by the enclosure of an intact branch in a Teflon cuvette. Main emitted monoterpenes were β trans-ocimene and linalool. The total monoterpenic emission rates thus recorded were found to reach maximum values around 30 μg gdry weight−1 h−1. The normalized emission rates calculated at 30 °C and 1000 μmol m−2 s−1 with Guenther's algorithm was 14.76, 8.65 and 4.05 μg gdry weight−1 h−1, respectively, for the total monoterpenes, β trans-ocimene and linalool. 相似文献
11.
12.
我国是全球二氟一氯甲烷（HCFC-22）的主要生产国,在HCFC-22的生产过程中,会产生大量的温室气体--三氟甲烷（HFC-23）。通过分析我国11个HFC-23减排清洁发展机制（CDM）项目的监测数据,确定HFC-23的排放因子,估算我国2000-2010年HFC-23的排放量,并预测了2011-2020年HFC-23的排放量和减排潜力。预计到2020年,我国HFC-23的排放量将达到2.3亿t CO2当量。如果HCFC-22企业能够实现自主减排,那么将为我国2020年CO2排放强度下降40%～45%的减排目标贡献3.2%～3.6%。 相似文献
13.
Emissions of biogenic volatile organic compounds (BVOC) were measured using a relaxed eddy accumulation (REA) technique on an above-canopy tower in a temperate forest (Changbai Mountain, Jilin province, China) during the 2010 and 2011 summer seasons. Solar global radiation and photosynthetically active radiation (PAR) were also measured. Based on PAR energy dynamic balance, an empirical BVOC emission and PAR transfer model was developed that includes the processes of BVOC emissions and PAR transfer above the canopy level, including PAR absorption and consumption, and scattering by gases, liquids, and particles (GLPs). Simulated emissions of isoprene and monoterpenes were in agreement with observations. The averages of the relative estimator biases for the flux were 39.3 % for isoprene, and 27.1 % for monoterpenes in the 2010 and 2011 growing seasons, with NMSE (normalized mean square error) values of 0.133 and 0.101, respectively. The observed and simulated mean diurnal variations of isoprene and monoterpenes in the 2010 and 2011 growing seasons were evaluated for the validation of the empirical model. Under observed atmospheric conditions, the sensitivity analysis showed that emissions of isoprene and monoterpenes were more sensitive to changes in PAR than to water vapor content or to the magnitude of the scattering factor. The emissions of isoprene and monoterpenes in the 2010 and 2011 growing seasons (from June to September) were estimated using this empirical model along with hourly observational data, with mean hourly emissions of 1.71 and 1.55 mg m?2 h?1 for isoprene, and 0.48 and 0.47 mg m?2 h?1 for monoterpenes in 2010 and 2011, respectively. As formaldehyde (HCHO) is considered as the main oxidation product of isoprene and monoterpenes, it is necessary to investigate the link between HCHO and BVOC emissions. GOME-2 HCHO vertical column densities (VCDs) can be used to estimate BVOC emission fluxes in the Changbai Mountain temperate forest. 相似文献
14.
Decreasing teleconnections with inter-site distance in monthly climatic data and tree-ring width networks in a mountainous Alpine area 总被引：3，自引：0，他引：3
C. Rolland 《Theoretical and Applied Climatology》2002,71(1-2):63-75
Summary The similarities in time series recorded at sites which are distant from each other are called teleconnections. In this paper,
the loss of such correlations with inter-site distance was investigated for both climatic and dendrochronological data sets,
with 70 tree-ring chronologies. A dense network of weather stations was studied in the southeastern French Alps, covering
complex climatic gradients over three departments. 78 sites with precipitation data (with a total of 48 756 monthly values),
and 48 stations that recorded temperature (with 20 722 monthly mean values) were analysed. In the same area, four coniferous
species (mountain pine and stone pine, European larch and Norway spruce) provided 37 ring-width chronologies for high elevation
sites near the timberline. Both silver fir and Norway spruce provided a second tree-ring chronology network for 33 different
sites at lower elevations.
The teleconnections between precipitation series were found to be higher than those observed for temperature over short distances,
but the maximum threshold distance was lower (193 km) compared to a positive correlation distance that exceeds 500 km for
temperature. The maximum temperatures had stronger teleconnections than minimum values (522 km versus 476 km), since the latter
are linked more with other site factors, such as slope, exposure and local topography.
As expected, the tree-ring chronologies showed weaker teleconnections than the climatic series, with a threshold distance
of 374 km obtained for all high elevation forests. The coniferous species with high intra-specific teleconnections over large
distances were, in decreasing importance, Pinus uncinata (> 500 km), Picea abies (477 km), Pinus cembra (over 254 km) and Larix decidua (over 189 km only). The two former species showed the highest intra-specific correlations (with mean correlation R=0.625 and 0.666). The dendrochronological teleconnections were found to have a extent lesser for trees species that depend
on rainfall (such as larch, and stone pine). They are enhanced, however, for temperature sensitive species such as spruce
and mountain pine (a drought resistant tree). Therefore, these two latter conifers appear to be especially suitable for climatic
reconstruction over large distances in mountainous areas. However, teleconnections within silver fir (Abies alba) and spruce chronologies were sharply reduced (over 131 km and 135 km) in lower elevation forests, underlining the interest
of timberline forests for dendroclimatology.
A better knowledge of the spatial correlations in climatic series and ring-width data may enable the optimisation of weather
station networks. It may also permit a better choice of weather stations used for dendroclimatology, either for tree-ring
and climate relationship calibration or for climate reconstructions. In dendrochronology, wood dating also requires the knowledge
of to what extent remote ring-width chronologies can be used.
Received September 11, 2000 Revised March 26, 2001 相似文献
15.
A combination of solid-phase microextraction (SPME) and gas chromatography can be successfully used both for establishing the qualitative composition of volatile organic compounds (VOC) emitted by leaf litter and for determining their emission rates. Taking as an example European larch litter, it is shown that dead plant material contains considerable amounts of volatile components as well as non-volatile compounds that can be VOC precursors formed as a result of enzymatic reactions. It is proposed to include the determination of extractable compounds into the methodology of studying litter as a source of atmospheric VOC. Some data on litter mass are reported and it is concluded that this data may be included into special models for emission evaluation. In this work the distribution coefficients of monoterpene hydrocarbons between the gas phase and polydimethylsiloxane fiber coating necessary for quantitative determinations in SPME were estimated. 相似文献
16.
F. Slemr G. Baumbach P. Blank U. Corsmeier F. Fiedler R. Friedrich M. Habram N. Kalthoff D. Klemp J. Kühlwein K. Mannschreck M. Möllmann-Coers K. Nester H.-J. Panitz P. Rabl J. Slemr U. Vogt B. Wickert 《Journal of Atmospheric Chemistry》2002,42(1):207-233
Emission inventories of NOx, CO, and individual volatile organic compounds (VOC), highly resolved in space and time, belong to the most important input parameters for chemistry and transport models (CTM) used for ozone prediction. Because of the decisive influence of the input quality on the outcome of CTM simulations, the quality of emission inventories has to be assessed. This paper presents an experimental evaluation of the highly resolved emission inventories for the city of Augsburg. The emissions of the city, determined in March and October 1998 using mass balance and tracer techniques, and derived from the measured receptor concentration ratios, were compared with emissions modeled from an emission inventory. The modeled CO emissions were in agreement with the measured ones within the combined experimental and model uncertainties. More detailed CO emission model simulations suggest that the tendency of calculated CO emissions being smaller than the measured ones may be due to higher traffic activity in Augsburg. Modeled NOx emissions were in agreement with the measured ones within the combined experimental and model uncertainties. Large deviations between modeled and measured values have been found for some individual NMHC compounds. The measured NMHC emission fingerprints were dominated by mobile sources. Substantial model predicted NMHC emissions from the solvent use could not be detected by measurements suggesting that they may not be correctly represented by the emission model. 相似文献
17.
Summary A coefficient-based vehicular exhaust emission model is being developed jointly with the variable-grid urban airshed model (UAM-V) of Systems Applications International (SAI), and integrated within a GIS (ArcInfo) framework. When coupled with a road network, traffic features and meteorological as well as geographical databases, this framework produces a Traffic Emission Information System (TEIS). With this TEIS, the emission coefficients of CO, NOx and VOC for Sydney in the calendar year 2000 are derived; and the emission rates of the pollutants are then estimated using sample traffic profile data for the Sydney metropolitan area. Finally, ongoing improvements to the system are presented. 相似文献
18.
P. J. Crutzen A. C. Delany J. Greenberg P. Haagenson L. Heidt R. Lueb W. Pollock W. Seiler A. Wartburg P. Zimmerman 《Journal of Atmospheric Chemistry》1985,2(3):233-256
Field measurement programs in Brazil during the dry seasons in August and September 1979 and 1980 have demonstrated the large importance of the continental tropics in global air chemistry. Many important trace gases are produced in large amounts over the continents. During the dry season, much biomass burning takes place, especially in the cerrado regions, leading to a substantial emission of air pollutants, such as CO, NO
x
, N2O, CH4 and other hydrocarbons. Ozone concentrations are enhanced due to photochemical reactions. The large biogenic organic emissions from tropical forests play an important role in the photochemistry of the atmosphere and explain why CO is present in such high concentrations in the boundary layer of the tropical forest. Carbon monoxide production may represent more than 3% of the net primary productivity of the tropical forests. Ozone concentrations in the boundary layer of the tropical forests indicate strong removal processes. Due to atmospheric supply of NO
x
by lightning, there is probably a large production of O3 in the free troposphere over the Amazon tropical forests. This is transported to the marine-free troposphere and to the forest boundary layer. 相似文献
19.
大气挥发性有机物（VOCs）是导致臭氧污染的关键前体物,是城市空气质量建模不可或缺的重要组成部分,但由于其非常复杂的构成和来源以及监测数据缺乏,目前对其模拟精度的了解仍非常有限。本文利用嵌套网格空气质量模式预报系统（NAQPMS）对珠江三角洲（简称珠三角）地区2017年9月21日至11月20日的VOCs开展了模拟试验,并利用光化学监测网8个地面站点的VOCs浓度监测数据,对模式模拟的关键VOCs组分进行了精度评估。结果发现,模式对强活性的甲苯、乙烯和二甲苯具有较高的模拟精度,模拟浓度偏差百分比为0.4%～26.6%,模拟能较好再现其日均浓度变化趋势和日变化的双峰特征。但是模式对化学反应活性强且与植物排放密切相关的异戊二烯具有很大的模拟偏差,偏差比近100%,无法再现其白天浓度高、夜间浓度低的观测日变化特征。通过分析发现,现有模拟系统主要考虑人为污染物排放而未考虑生物源排放,可能是导致这一模拟偏差的关键原因。同时,评估结果也表明模式在VOCs空间分布模拟上仍面临很大的不确定性。本文结果揭示了珠三角VOCs模拟面临的关键不确定性,表明融合VOCs观测数据来揭示并减小VOCs模拟的不确定性具有非常迫切的需求。 相似文献
20.
The present study estimates the net emission of carbon from the forest sector in India. For the reference year (1986), the gross emission from deforestation in that year, plus committed emissions from deforestation in the preceding years, is estimated to be 64 × 106 t of C. The carbon sequestration (or net woody biomass accumulation in trees for long-term storage) from the area brought under tree plantations and the existing forest area under forest succession is estimated to offset the gross carbon emission in India, leading to no net emissions of carbon from the forest sector. Medium-term projections for India (for the year 2011) show that under a business as usual scenario at current rates of afforestation, projected carbon emissions would continue to be balanced by sequestration. 相似文献