Isoprene emissions from vegetation and hydrocarbon emissions from bushfires in tropical Australia

Ayers, G. P.; Gillett, R. W.

doi:10.1007/bf00048045

Cited by 31 publications

(11 citation statements)

References 25 publications

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“…Pioneering experiments to characterize fire emissions were conducted in South America , Africa (Delmas, 1982), and Australia (Ayers and Gillett, 1988). In the beginning of the 1990s, the experiments of these individual groups were followed by a number of large international biomass burning experiments in various ecosystems throughout the world.…”

Section: T T Van Leeuwen and G R Van Der Werf: Spatio-temporal Vamentioning

confidence: 99%

Spatial and temporal variability in the ratio of trace gases emitted from biomass burning

Leeuwen¹,

Werf²

2011

Atmos. Chem. Phys.

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Abstract. Fires are a major source of trace gases and aerosols to the atmosphere. The amount of biomass burned is becoming better known, most importantly due to improved burned area datasets and a better representation of fuel consumption. The spatial and temporal variability in the partitioning of biomass burned into emitted trace gases and aerosols, however, has received relatively little attention. To convert estimates of biomass burned to trace gas and aerosol emissions, most studies have used emission ratios (or emission factors (EFs)) based on the arithmetic mean of field measurement outcomes, stratified by biome. However, EFs vary substantially in time and space, even within a single biome. In addition, it is unknown whether the available field measurement locations provide a representative sample for the various biomes. Here we used the available body of EF literature in combination with satellite-derived information on vegetation characteristics and climatic conditions to better understand the spatio-temporal variability in EFs. While focusing on CO, CH 4 , and CO 2 , our findings are also applicable to other trace gases and aerosols. We explored relations between EFs and different measurements of environmental variables that may correlate with part of the variability in EFs (tree cover density, vegetation greenness, temperature, precipitation, and the length of the dry season). Although reasonable correlations were found for specific case studies, correlations based on the full suite of available measurements were lower and explained about 33%, 38%, 19%, and 34% of the variability for respectively CO, CH 4 , CO 2 , and the Modified Combustion Efficiency (MCE). This may be partly due to uncertainties in the environmental variables, differences in measurement techniques for EFs, assumptions on the ratio between flaming and smoldering combustion, and incomplete information on the location and timing of EF Correspondence to: T. T. van Leeuwen (thijs.van.leeuwen@falw.vu.nl) measurements. We derived new mean EFs, using the relative importance of each measurement location with regard to fire emissions. These weighted averages were relatively similar to the arithmetic mean. When using relations between the environmental variables and EFs to extrapolate to regional and global scales, we found substantial differences, with for savannas 13% and 22% higher CO and CH 4 EFs than the arithmetic mean of the field studies, possibly linked to an underrepresentation of woodland fires in EF measurement locations. We argue that from a global modeling perspective, future measurement campaigns could be more beneficial if measurements are made over the full fire season, and if relations between ambient conditions and EFs receive more attention.

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Section: T T Van Leeuwen and G R Van Der Werf: Spatio-temporal Vamentioning

confidence: 99%

Spatial and temporal variability in the ratio of trace gases emitted from biomass burning

Leeuwen¹,

Werf²

2011

Atmos. Chem. Phys.

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“…Isoprene has a very short lifetime (< 4 hours during daytime) and a complex vertical structure has been reported at rural and urban sites (e.g., Andronache et al, 1994). An important vertical gradient has been observed in the boundary layer in tropical areas, which shows a decrease in isoprene mixing ratios with altitude (Rassmussen and Khalil, 1988;Ayers and Gillett, 1988). Therefore, our measurements made at the surface likely correspond to maximmun concentrations of isoprene in the regional savannah atmosphere.…”

Section: Concentration Of C 2 To C 6 Hydrocarbons At Clean Sitesmentioning

confidence: 99%

“…There are only a limited number of measurements, which show a large variability (Lamontagne et al, 1974;Shaw et al, 1983;Greemberg et al, 1985;Ayers and Gillett, 1988;Rasmussen and Khalil, 1988;Yokouchi and Ambe, 1988;Zimmerman et al, 1988;Bonsang et al, 1990Bonsang et al, , 1991Prinn, 1990, 1993;Plass et al, 1990;Andronache et al, 1994;Bottenheim and Shepherd, 1995). In this paper, as part of a chemical characterization of the atmosphere of the Venezuelan savannah climatic region, we report the concentrations of C2 to C6 hydrocarbons measured at clean 'pristine' sites and locations affected by emissions of hydrocarbons from oil and gas producing fields.…”

Section: Introductionmentioning

confidence: 99%

Natural and anthropogenic C2 to C6 hydrocarbons in the central-eastern Venezuelan atmosphere during the rainy season

et al. 1996

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The levels of low molecular weight hydrocarbons were measured at pristine sites and rural locations affected by hydrocarbon emissions from oil and gas producing fields in Venezuela. At the clean sites, lower concentrations of C2 to C6 alkanes were observed, whereas, in comparison with remotes sites, very much higher levels were measured at the polluted sites. Alkenes present relatively high concentrations, with isoprene being the most abundant, all over the study region. The main sources of alkenes are likely to be natural, mainly from vegetation. The levels of alkanes recorded at the clean sites and the alkene levels found everywhere in the region are in agreement with the values reported for other clean sites in the tropics. The increase of ozone production capacity due to the anthropogenic emissions of alkanes from oil and gas fields was estimated. Due to the presence in the atmosphere of important amounts of naturally emitted isoprene, ethene and propene, which makes a substantial contribution to the reactivity of the hydrocarbon mixture, a small increase (< 5%) was estimated to occur in the capacity of the ozone production at a regional scale during the rainy season.

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“…1 dm 3 to several tens of dm 3 • Glass or stainless-steel sample containers cause less contamination problems but are more expensive than plastic bags. In the past, glass vessels have been widely used for air sampling [21][22][23][24][25][26], but more recently mostly stainless-steel canisters have become more popular [1][2][3][4][5]7,14,17,[27][28][29][30][31][32][33][34][35][36][37][38][39]. Stainless-steel sample canisters are nowadays in general equipped with metal bellows valves [1][2][3][4][5]14,16,19,28,29], which avoids all polymenc seals etc.…”

Section: Whole-air Samplingmentioning

confidence: 99%

Sampling of organic volatiles in the atmosphere at moderate and low pollution levels

Rudolph¹,

Müller²,

Koppmann³

1990

Analytica Chimica Acta

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Several techntques are avatlable for measunng organic volattles m the atmosphere. For measurements at low and moderate pollUtlon levels (between several p.g m-3 and a fraction of a p.g m-3 ), the eXIstmg methods can be adopted to a broad range of different compounds. Whole-atr samphng m stamless-steel containers With metal bellows valves combmed With subsequent gas chromatograpluc separatIOn after preconcentratlon 10 the laboratory IS probably the best procedure for low and medium molecular Weight trace gases of moderate or low polanty and reasonable cherrncal stability (e.g., hydrocarbons and halocarbons). For orgamc compounds of lower volatility, adsorptlve samphng on non-polar porous orgaruc polymers (e.g, Tenax) and thermal desorptlon combmed WIth cryotrappmg and gas chromatograpluc separation of the sampled compounds IS Widely used However, there are often substantial problems due to artefact formatIOn or loss reactIOns Owmg to the generally larger sample volumes, these problems are even more pronounced for sorptlve samphng techntques combmed with sample recovery by solvent extraction. Unfortunately, the general understandmg of the vanous processes of sample degradatlon due to cherrncal reactlons of reactlve components of the atmosphere With each other or WIth the sorbent IS not yet suffiCient to allow reasonable estlmates of the extent of such mterferences Without elaborate test procedures. Keywords. Au, Samplmg procedures; Extractlon, Orgamc volatdesThe demand for accurate, reliable and sensitive techniques for the monitoring of organic trace constituents in the atmosphere has increased tremendously in the recent past. The reasons include not only a growing concern for the quality of the environment but also the realization that atmosphenc pollution is not only a local problem. At the same time, the number of different organic compounds which are emitted into the atmosphere has been rising steadily. Further, it has been recognized that several substances which had been considered harmless can pose serious hazards to the enVIronment. There is a broad range of techniques for the determination of organic compounds at trace levels wmch are sufficiently sensitive and selective. Chromatography (predominantly LC and GC) is the most widely used method and allows the identification and quantification of organic compounds in sub-nanogram amounts. With few exceptions, the analysis itself is carried out in the laboratory, which means that the sample has somehow to be transported to the laboratory. For many kinds of environmental measurements, representative and contamination-or lossfree sampling often requires substantial efforts and iD general air is one of the most difficult environmenal media for sampling. The problems are easy to understand but difficult to solve. Sample contamers for air are not only more complicated than those for solid or liquid material but also, owing to the low density of air, the volume which has to be collected for an analysis for trace components is generally larger than that for...

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Isoprene emissions from vegetation and hydrocarbon emissions from bushfires in tropical Australia

Cited by 31 publications

References 25 publications

Spatial and temporal variability in the ratio of trace gases emitted from biomass burning

Spatial and temporal variability in the ratio of trace gases emitted from biomass burning

Natural and anthropogenic C2 to C6 hydrocarbons in the central-eastern Venezuelan atmosphere during the rainy season

Sampling of organic volatiles in the atmosphere at moderate and low pollution levels

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