Sesquiterpene emissions from loblolly pine and their potential contribution to biogenic aerosol formation in the Southeastern US (original) (raw)
Related papers
Atmospheric Environment, 2006
Recent research pointed out the question of missing OH reactivity in a forest system and the question for unknown highly reactive biogenic emissions. In this study we show that coniferous forests are an important source of highly reactive hydrocarbons, the sesquiterpenes. We investigated the seasonality of terpene emissions from Scots pine to work out influences on atmospheric chemistry in different seasons for both mono-and sesquiterpenes. Especially sesquiterpenes (C 15 ) change dramatically in their contribution to the terpene emissions of Scots pine. Fourteen sesquiterpenes and oxygenated compounds were found in the emissions. In spring, the pattern was most complex with all 14 compounds being emitted, whereas in summer and fall it was reduced to 1,8-cineol and camphor. The emission pattern of the monoterpenes varied only slightly. The main compounds emitted were a-pinene, b-pinene, and 3-carene representing up to 90% of the total terpene emission. The total monoterpene emission rates varied from below detection limit to 460 pmol m À2 s À1 with highest emission rates found in June. Standard emission rates of the main compounds calculated from the monthly measured diurnal emission courses varied considerably over the year. Highest values were found in spring and early summer with up to 700 pmol m À2 s À1 .
Mountain birch – potentially large source of sesquiterpenes into high latitude atmosphere
Biogeosciences, 2009
Emissions of volatile organic compounds (VOCs) from mountain birches were measured in Abisko, northern Sweden. Mountain birches make up the majority of the tree biomass in Scandinavian high latitudes, a region subject to significant climate warming. The measurements were carried out in two growing seasons. The emissions of four branches, each from a different individual tree, were measured in June-August 2006 and one of them again in July 2007. The measurements were conducted using a dynamic flow through chamber covered with Teflon film. The studied mountain birches were found to emit substantial amounts of linalool, monoterpenes and sesquiterpenes. The monoterpene emission was dominated by sabinene. The magnitude and composition of the sesquiterpene emission changed dramatically between the years. For example, the average α-farnesene emission potential in 2006 was almost 2600 ng g −1 dw h −1 (3.5 pmol g −1 dw s −1) while in 2007 αfarnesene was not detected at all. Also the emissions of other sesquiterpenes decreased in 2007 to a fraction of that in 2006. One possible explanation for the change in emissions is the herbivory damage that occurred in the area in 2004. Herbivory is known to enhance the emissions of sesquiterpenes, especially those of α-farnesene, and the effect may last for several years.
Atmospheric Chemistry and Physics, 2021
Secondary organic aerosols (SOAs) formed from biogenic volatile organic compounds (BVOCs) constitute a significant fraction of atmospheric particulate matter and have been recognized to significantly affect the climate and air quality. Atmospheric SOA particulate mass yields and chemical composition result from a complex mixture of oxidation products originating from a diversity of BVOCs. Many laboratory and field experiments have studied SOA particle formation and growth in the recent years. However, a large uncertainty still remains regarding the contribution of BVOCs to SOA. In particular, organic compounds formed from sesquiterpenes have not been thoroughly investigated, and their contribution to SOA remains poorly characterized. In this study, a Filter Inlet for Gases and Aerosols (FI-GAERO) combined with a high-resolution time-of-flight chemical ionization mass spectrometer (CIMS), with iodide ionization, was used for the simultaneous measurement of gas-phase and particle-phase oxygenated compounds. The aim of the study was to evaluate the relative contribution of sesquiterpene oxidation products to SOA in a springtime hemiboreal forest environment. Our results revealed that monoterpene and sesquiterpene oxidation products were the main contributors to SOA particles. The chemical composition of SOA particles was compared for times when either monoterpene or sesquiterpene oxidation products were dominant and possible key oxidation products for SOA particle formation were identified for both situations. Surprisingly, sesquiterpene oxidation products were the predominant fraction in the particle phase in some periods, while their gas-phase concentrations remained much lower than those of monoterpene products. This can be explained by favorable and effective partitioning of sesquiterpene products into the particle phase. The SOA particle volatility determined from measured thermograms increased when the concentration of sesquiterpene oxidation products in SOA particles was higher than that of monoterpenes. Overall, this study demonstrates that sesquiterpenes may have an important role in atmospheric SOA formation and oxidation chemistry, in particular during the spring recovery period. 1 Introduction Volatile organic compounds (VOCs) are ubiquitous constituents of Earth's atmosphere that are emitted from both biogenic and anthropogenic sources (e.g., Kansal, 2009). Anthropogenic VOCs (AVOCs) may predominate in urban areas, but the source strength of biogenic VOCs (BVOCs) ex-Published by Copernicus Publications on behalf of the European Geosciences Union.
Monoterpene emission from ponderosa pine
Journal of Geophysical Research, 1994
We explore the variability in monoterpene emissions from ponderosa pine beyond that which can be explained by temperature alone. Specifi•y, we examine the roles that photosynthesis and neexlle monoterpene concentrations play in controlling emissions. We measure monoterpene concentrations and emissions, photosynthesis, temperature, and light availability in the late spring and late summer in a ponderosa pine forest in cenlxal Oregon. We use a combination of measurements from cuvelles and Teflon bag enclosures to show that photosynthesis is not correlated with emissions in the short term. We also show that needle monoterpene concentrations are highly correlmexi with emissions for two compounds, ot-pinene and •-pinene, but that A-carene concentrations are not conelated with emissions. We suggest that direct effects of light and photosynthesis do not need to be included in emission algorithms. Our results indicate that the role of needle concentration bears further investigation; our results for ot-pinene and •-pinene are explainable by a Raoult's law relationship, but we cannot yet explain the cause of our results with A-carene.