scholarly journals Concentrations and fluxes of biogenic volatile organic compounds above a Mediterranean macchia ecosystem in Western Italy

2009 ◽  
Vol 6 (1) ◽  
pp. 2183-2216 ◽  
Author(s):  
B. Davison ◽  
R. Taipale ◽  
B. Langford ◽  
P. Misztal ◽  
S. Fares ◽  
...  
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Three Dimensional ◽  
Proton Transfer Reaction ◽  
Emission Rates ◽  
Biogenic Volatile Organic Compounds ◽  
Eddy Covariance Method ◽  
Mixing Ratios ◽  
Sonic Anemometers ◽  
Volatile Organic

Abstract. Emission rates and concentrations of biogenic volatile organic compounds (BVOCs) were measured at a Mediterranean coastal site at Castelporziano, approximately 25 km south-west of Rome, between 7 May and 3 June 2007, as part of the ACCENT-VOCBAS field campaign on biosphere-atmosphere interactions. Concentrations and emission rates were measured using the disjunct eddy covariance method utilizing three different proton transfer reaction mass spectrometers (PTR-MS) for BVOC mixing ratio measurements and sonic anemometers for three-dimensional high-frequency wind measurements. Depending on the measurement period and the instrument, the median volume mixing ratios were 1.6–3.5 ppbv for methanol, 0.4–1.5 ppbv for acetaldehyde, 1.0–2.5 ppbv for acetone, 0.10–0.17 ppbv for isoprene, and 0.18–0.30 ppbv for monoterpenes. A diurnal cycle in mixing ratios was apparent with daytime maxima for methanol, acetaldehyde, acetone, and isoprene. The median fluxes were 370–440 μg m−2 h−1 for methanol, 180–360 μg m−2 h−1 for acetaldehyde, 180–450 μg m−2 h−1 for acetone, 71–290 μg m−2 h−1 for isoprene, and 240–860 μg m−2 h−1 for monoterpenes.

scholarly journals Concentrations and fluxes of biogenic volatile organic compounds above a Mediterranean macchia ecosystem in western Italy

2009 ◽  
Vol 6 (8) ◽  
pp. 1655-1670 ◽  
Author(s):  
B. Davison ◽  
R. Taipale ◽  
B. Langford ◽  
P. Misztal ◽  
S. Fares ◽  
...  
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Proton Transfer Reaction ◽  
Emission Rates ◽  
Biogenic Volatile Organic Compounds ◽  
Mass Spectrometers ◽  
High Resolution Data ◽  
Mixing Ratios ◽  
Volatile Organic ◽  
Measurement Period

Abstract. Emission rates and concentrations of biogenic volatile organic compounds (BVOCs) were measured at a Mediterranean coastal site at Castelporziano, approximately 25 km south-west of Rome, between 7 May and 3 June 2007, as part of the ACCENT-VOCBAS field campaign on biosphere–atmosphere interactions. Concentrations and emission rates were measured using the disjunct eddy covariance (DEC) method utilizing three different proton transfer reaction mass spectrometers (PTR-MS) so allowing a comparison between the instruments. The high resolution data from the PTR-MS instruments considerably enhances the original BEMA measurements of the mid 1990s. Depending on the measurement period, the volume mixing ratios were in the range 1.6–3.5 ppbv for methanol, 0.44–1.3 ppbv for acetaldehyde, 0.96–2.1 ppbv for acetone, 0.10–0.14 ppbv for isoprene, and 0.13–0.30 ppbv for monoterpenes. A diurnal cycle in mixing ratios was apparent with daytime maxima for methanol, acetaldehyde, acetone, and isoprene. The fluxes ranged from 370–440 μg m−2 h−1 for methanol, 180–360 μg m−2 h−1 for acetaldehyde, 180–450 μg m−2 h−1 for acetone, 71–290 μg m−2 h−1 for isoprene, and 240–860 μg m−2 h−1 for monoterpenes. From the measured flux data (7 May–3 June) an average basal emission rate for the Macchia vegetation was calculated of 430 μg m−2 h−1 for isoprene and 1100 μg m−2 h−1 for monoterpenes.

scholarly journals Diel and seasonal changes of biogenic volatile organic compounds within and above an Amazonian rainforest

2015 ◽  
Vol 15 (6) ◽  
pp. 3359-3378 ◽  
Author(s):  
A. M. Yáñez-Serrano ◽  
A. C. Nölscher ◽  
J. Williams ◽  
S. Wolff ◽  
E. Alves ◽  
...  
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Ambient Air ◽  
Dry Season ◽  
Solar Irradiation ◽  
Biogenic Volatile Organic Compounds ◽  
Wet Season ◽  
Mixing Ratios ◽  
Volatile Organic ◽  
Amazonian Rainforest

Abstract. The Amazonian rainforest is a large tropical ecosystem, which is one of the last pristine continental terrains. This ecosystem is ideally located for the study of diel and seasonal behaviour of biogenic volatile organic compounds (BVOCs) in the absence of local human interference. In this study, we report the first atmospheric BVOC measurements at the Amazonian Tall Tower Observatory (ATTO) site, located in central Amazonia. A quadrupole proton-transfer-reaction mass spectrometer (PTR-MS), with seven ambient air inlets, positioned from near ground to about 80 m (0.05, 0.5, 4, 24, 38, 53 and 79 m above the forest floor), was deployed for BVOC monitoring. We report diel and seasonal (February–March 2013 as wet season and September 2013 as dry season) ambient mixing ratios for isoprene, monoterpenes, isoprene oxidation products, acetaldehyde, acetone, methyl ethyl ketone (MEK), methanol and acetonitrile. Clear diel and seasonal patterns were observed for all compounds. In general, lower mixing ratios were observed during night, while maximum mixing ratios were observed during the wet season (February–March 2013), with the peak in solar irradiation at 12:00 LT (local time) and during the dry season (September 2013) with the peak in temperature at 16:00 LT. Isoprene and monoterpene mixing ratios were the highest within the canopy with a median of 7.6 and 1 ppb, respectively (interquartile range (IQR) of 6.1 and 0.38 ppb) during the dry season (at 24 m, from 12:00 to 15:00 LT). The increased contribution of oxygenated volatile organic compounds (OVOCs) above the canopy indicated a transition from dominating forest emissions during the wet season (when mixing ratios were higher than within the canopy), to a blend of biogenic emission, photochemical production and advection during the dry season when mixing ratios were higher above the canopy. Our observations suggest strong seasonal interactions between environmental (insolation, temperature) and biological (phenology) drivers of leaf BVOC emissions and atmospheric chemistry. Considerable differences in the magnitude of BVOC mixing ratios, as compared to other reports of Amazonian BVOC, demonstrate the need for long-term observations at different sites and more standardized measurement procedures, in order to better characterize the natural exchange of BVOCs between the Amazonian rainforest and the atmosphere.

scholarly journals Fluxes and concentrations of volatile organic compounds above central London, UK

2009 ◽  
Vol 9 (4) ◽  
pp. 17297-17333 ◽  
Author(s):  
B. Langford ◽  
E. Nemitz ◽  
E. House ◽  
G. J. Phillips ◽  
D. Famulari ◽  
...  
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Transfer Reaction ◽  
Proton Transfer Reaction ◽  
Traffic Density ◽  
Mixing Ratios ◽  
Oxygenated Compounds ◽  
Volatile Organic ◽  
Benzene Toluene ◽  
The Uk

Abstract. Concentrations and fluxes of eight volatile organic compounds (VOCs) were measured during October 2006 from a high telecom tower above central London, as part of the CityFlux contribution to the REPARTEE I campaign. A continuous flow disjunct eddy covariance technique with analysis by proton transfer reaction mass spectrometry was used. Daily averaged VOC mixing ratios were within the range 1–19 ppb for the oxygenated compounds (methanol, acetaldehyde and acetone) and 0.2–1.3 ppb for the aromatics (benzene, toluene and ethylbenzene). Typical VOC fluxes were in the range 0.1–1.0 mg m−2 h−1. There was a non-linear relationship between VOC fluxes and traffic density for most of the measured compounds. Traffic activity was estimated to account for approximately 70% of the aromatic compound fluxes, whereas non-traffic related sources were found to be more important for methanol and isoprene fluxes. The measured fluxes were comparable to the estimates of the UK national atmospheric emission inventory for the aromatic VOCs and CO. In contrast, fluxes of the oxygenated compounds were about three times larger than inventory estimates. For isoprene and acetonitrile this difference was many times larger. At temperatures over 25°C it is estimated that more than half the isoprene observed in central London is of biogenic origin.

scholarly journals Mixing ratios and eddy covariance flux measurements of volatile organic compounds from an urban canopy (Manchester, UK)

2008 ◽  
Vol 8 (1) ◽  
pp. 245-284 ◽  
Author(s):  
B. Langford ◽  
B. Davison ◽  
E. Nemitz ◽  
C. N. Hewitt
Keyword(s):  
Volatile Organic Compounds ◽  
Eddy Covariance ◽  
Organic Compounds ◽  
Urban Canopy ◽  
Proton Transfer Reaction ◽  
Anthropogenic Sources ◽  
Emissions Inventory ◽  
Mixing Ratios ◽  
Volatile Organic ◽  
The Individual

Abstract. Concentrations and fluxes of six volatile organic compounds (VOC) were measured above the city of Manchester (UK) during the summer of 2006. A proton transfer reaction-mass spectrometer was used for the measurement of concentrations, and fluxes were calculated using both the disjunct and the virtual disjunct eddy covariance techniques. The two flux systems, which operated in alternate half hours, showed reasonable agreement, with R2 values ranging between 0.2 and 0.8 for the individual analytes. On average, fluxes measured in the disjunct mode were lower than those measured in the virtual mode by approximately 19%, of which at least 8% can be attributed to the differing measurement frequencies of the two systems and the subsequent attenuation of high frequency flux contributions. Observed fluxes are thought to be largely controlled by anthropogenic sources, with vehicle emissions the major contributor. However both evaporative and biogenic emissions may account for a fraction of the isoprene present. Fluxes of the oxygenated compounds were highest on average, ranging between 60–89 μg m−2 h−1, whereas the fluxes of aromatic compounds were lower, between 19–42 μg m−2 h−1. The observed fluxes of benzene were up-scaled to give a city wide emission estimate which was found to be significantly lower than that of the National Atmospheric Emissions Inventory (NAEI).

scholarly journals Measurement report: Variability in the composition of biogenic volatile organic compounds in a Southeastern US forest and their role in atmospheric reactivity

2021 ◽  
Vol 21 (20) ◽  
pp. 15755-15770
Author(s):  
Deborah F. McGlynn ◽  
Laura E. R. Barry ◽  
Manuel T. Lerdau ◽  
Sally E. Pusede ◽  
Gabriel Isaacman-VanWertz
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Growing Season ◽  
Mixing Ratio ◽  
Biogenic Volatile Organic Compounds ◽  
Mixing Ratios ◽  
Southeastern Us ◽  
Atmospheric Reactivity ◽  
Volatile Organic ◽  
The Impact

Abstract. Despite the significant contribution of biogenic volatile organic compounds (BVOCs) to organic aerosol formation and ozone production and loss, there are few long-term, year-round, ongoing measurements of their volume mixing ratios and quantification of their impacts on atmospheric reactivity. To address this gap, we present 1 year of hourly measurements of chemically resolved BVOCs between 15 September 2019 and 15 September 2020, collected at a research tower in Central Virginia in a mixed forest representative of ecosystems in the Southeastern US. Mixing ratios of isoprene, isoprene oxidation products, monoterpenes, and sesquiterpenes are described and examined for their impact on the hydroxy radical (OH), ozone, and nitrate reactivity. Mixing ratios of isoprene range from negligible in the winter to typical summertime 24 h averages of 4–6 ppb, while monoterpenes have more stable mixing ratios in the range of tenths of a part per billion up to ∼2 ppb year-round. Sesquiterpenes are typically observed at mixing ratios of <10 ppt, but this represents a lower bound in their abundance. In the growing season, isoprene dominates OH reactivity but is less important for ozone and nitrate reactivity. Monoterpenes are the most important BVOCs for ozone and nitrate reactivity throughout the year and for OH reactivity outside of the growing season. To better understand the impact of this compound class on OH, ozone, and nitrate reactivity, the role of individual monoterpenes is examined. Despite the dominant contribution of α-pinene to total monoterpene mass, the average reaction rate of the monoterpene mixture with atmospheric oxidants is between 25 % and 30 % faster than α-pinene due to the contribution of more reactive but less abundant compounds. A majority of reactivity comes from α-pinene and limonene (the most significant low-mixing-ratio, high-reactivity isomer), highlighting the importance of both mixing ratio and structure in assessing atmospheric impacts of emissions.

scholarly journals From emissions to ambient mixing ratios: on-line seasonal field measurements of volatile organic compounds over a Norway spruce dominated forest in central Germany

2013 ◽  
Vol 13 (11) ◽  
pp. 30187-30232 ◽  
Author(s):  
E. Bourtsoukidis ◽  
J. Williams ◽  
J. Kesselmeier ◽  
S. Jacobi ◽  
B. Bonn
Keyword(s):  
Volatile Organic Compounds ◽  
Norway Spruce ◽  
Organic Compounds ◽  
Atmospheric Chemistry ◽  
Temperature Dependency ◽  
Emission Rates ◽  
Temperature Dependent ◽  
Central Germany ◽  
Mixing Ratios ◽  
Volatile Organic

Abstract. Biogenic volatile organic compounds (BVOC) are substantial contributors to atmospheric chemistry and physics and demonstrate the close relationship between biosphere and atmosphere. Their emission rates are highly sensitive to meteorological and environmental changes with concomitant impacts on atmospheric chemistry. We have investigated seasonal isoprenoid and oxygenated VOC (oxVOC) fluxes from a Norway spruce (Picea abies) tree in Central Germany and explored the emission responses under various atmospheric conditions. Emission rates were quantified by using dynamic branch enclosure and Proton Transfer Reaction–Mass Spectrometry (PTR-MS) techniques. Additionally, ambient mixing ratios were derived through application of a new box model treatment on the dynamic chamber measurements. These are compared in terms of abundance and origin with the corresponding emissions. Isoprenoids govern the BVOC emissions from Norway spruce, with monoterpenes and sesquiterpenes accounting for 50.8 ± 7.2% and 19.8 ± 8.1% respectively of the total emissions. Normalizing the VOC emission rates, we have observed a trend of reduction of carbon containing emissions from April to November, with an enhancement of oxVOC. Highest emission rates were observed in June for all measured species, with the exception of sesquiterpenes that were emitted most strongly in April. We exploit the wide range of conditions experienced at the site to filter the dataset with a combination of temperature, ozone and absolute humidity values in order to derive the emission potential and temperature dependency development for the major chemical species investigated. A profound reduction of monoterpene emission potential (E30) and temperature dependency (β) was found under low temperature regimes, combined with low ozone levels (E30MT, LTLO3=56 ± 9.1 ng g(dw)−1 h−1, βMT,LTLO3=0.03±0.01 K−1) while a combination of both stresses was found to alter their emissions responses with respect to temperature substantially (E30MT,HTHO3=1420.1 ± 191.4 ng g(dw)−1 h−1, βMT,HTHO3=0.15 ± 0.02 K−1). Moreover, we have explored compound relationships under different atmospheric condition sets, addressing possible co-occurrence of emissions under specific conditions. Finally, we evaluate the temperature dependent algorithm that seems to describe the temperature dependent emissions. Highest emission deviations were observed for monoterpenes and these emission fluctuations were attributed to a fraction which is triggered by an additional light dependency.

scholarly journals Emissions of isoprenoids and oxygenated biogenic volatile organic compounds from a New England mixed forest

2010 ◽  
Vol 10 (11) ◽  
pp. 28565-28633
Author(s):  
K. A. McKinney ◽  
B. H. Lee ◽  
A. Vasta ◽  
T. V. Pho ◽  
J. W. Munger
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Forest Canopy ◽  
Emission Rate ◽  
Mixed Forest ◽  
Emission Rates ◽  
Biogenic Volatile Organic Compounds ◽  
Methanol Production ◽  
Short Period ◽  
Volatile Organic

Abstract. Fluxes of biogenic volatile organic compounds, including isoprene, monoterpenes, and oxygenated VOCs measured above a mixed forest canopy in western Massachusetts during the 2005 and 2007 growing seasons are reported. Measurements were made using proton transfer reaction mass spectrometry (PTR-MS) and converted to fluxes using the disjunct eddy covariance technique. Isoprene was by far the predominant BVOC emitted at this site, with summer mid-day average fluxes of 5.3 and 4.4 mg m−2 h−1 in 2005 and 2007, respectively. In comparison, mid-day average fluxes of monoterpenes were 0.21 and 0.15 mg m−2 h−1 in each of these years. On short times scales (days), the diel pattern in emission rate compared well with a standard emission algorithm for isoprene. The general shape of the seasonal cycle and the observed decrease in isoprene emission rate in early September was, however, not well captured by the model. Monoterpene emission rates exhibited dependence on light as well as temperature, as determined from the improved fit to the observations obtained by including a light-dependent term in the model. The mid-day average flux of methanol from the canopy was 0.14 mg m−2 h−1 in 2005 and 0.19 mg m−2 h−1 in 2007, but the maximum flux was observed in spring (29 May 2007), when the flux reached 1.0 mg m−2 h−1. This observation is consistent with enhanced methanol production during leaf expansion. Summer mid-day fluxes of acetone were 0.15 mg m−2 h−1 during a short period in 2005, but only 0.03 mg m−2 h−1 averaged over 2007. Episodes of negative fluxes of oxygenated VOCs, particularly acetone, were observed periodically, especially in 2007. Thus, deposition within the canopy could help explain the low season-averaged flux of acetone in 2007. Fluxes of species of biogenic origin at mass-to-charge (m/z) ratios of 73 (0.05 mg m−2 h−1 in 2005; 0.03 mg m−2 h−1 in 2007) and 153 (5 μg m−2 h−1 in 2007), possibly corresponding to methyl ethyl ketone and an oxygenated terpene, respectively, were also observed.

scholarly journals Seasonal and diurnal variations of biogenic volatile organic compounds in highland and lowland ecosystems in southern Kenya

2021 ◽  
Author(s):  
Yang Liu ◽  
Simon Schallhart ◽  
Ditte Taipale ◽  
Toni Tykkä ◽  
Matti Räsänen ◽  
...  
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Atmospheric Chemistry ◽  
Daily Maximum ◽  
Mixing Ratio ◽  
Biogenic Volatile Organic Compounds ◽  
Mixing Ratios ◽  
Seasonal And Diurnal Variations ◽  
Volatile Organic ◽  
Dry Seasons

Abstract. The East African lowland and highland areas consist of water-limited and humid ecosystems. The magnitude and seasonality of biogenic volatile organic compounds (BVOCs) emissions from these functionally contrasting ecosystems are limited due to a scarcity of direct observations. We measured mixing ratios of BVOCs from two contrasting ecosystems, humid highlands with agroforestry and dry lowlands with bushland, grassland, and agriculture mosaics, during both the rainy and dry seasons of 2019 in southern Kenya. We present the diurnal and seasonal characteristics of BVOC mixing ratios and their reactivity, and estimated emission factors (EFs) for certain BVOCs from the African lowland ecosystem based on field measurements. The most abundant BVOCs were isoprene and monoterpenoids (MTs), with isoprene contributing > 70 % of the total BVOC mixing ratio during daytime, while MTs accounted for > 50 % of the total BVOC mixing ratio during nighttime at both sites. The contributions of BVOCs to the local atmospheric chemistry were estimated by calculating the reactivity towards the hydroxyl radical (OH), ozone (O3), and the nitrate radical (NO3). Isoprene and MTs contributed the most to the reactivity of OH and NO3, while sesquiterpenes dominated the contribution of organic compounds to the reactivity of O3. The mixing ratio of isoprene measured in this study was lower to that measured in the relevant ecosystems in west and south Africa, while that of monoterpenoids was similar. Isoprene mixing ratios peaked daily between 16:00 and 20:00 with a maximum mixing ratio of 809 parts per trillion by volume (pptv) and 156 pptv in the highlands, and 115 pptv and 25 pptv in the lowlands, during the rainy and dry seasons, respectively. MT mixing ratios reached their daily maximum between midnight and early morning (usually 04:00 to 08:00) with mixing ratios of 254 pptv and 56 pptv in the highlands, and 89 pptv and 7 pptv in the lowlands, in the rainy and dry seasons, respectively. The dominant species within the MT group were limonene, α-pinene, and β-pinene. EFs for isoprene, MTs, and 2-methyl-3-buten-2-ol (MBO) were estimated using an inverse modeling approach. The estimated EFs for isoprene and β-pinene agreed very well with what is currently assumed in the world’s most extensively used biogenic emissions model, the Model of Emissions of Gases and Aerosols from Nature (MEGAN), for warm C4 grass, but the estimated EFs for MBO, α-pinene, and especially limonene, were significantly higher than that assumed in MEGAN for the relevant plant functional type. Additionally, our results indicate that the EF for limonene might be seasonally dependent in savanna ecosystems.

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