Are plant emissions green?

Guenther, Alex

doi:10.1038/452701a

Cited by 18 publications

(10 citation statements)

References 9 publications

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“…Such interpretations were supported by the recent reports about an OH recycling process by isoprene oxidation which may explain such high OH levels [Lelieveld et al, 2008]. These findings give rise to new discussions about the interactions of biogenic emissions and atmospheric chemistry [Guenther, 2008] and to isoprene and monoterpene flux estimates which may be underestimated by at least a factor of five.…”

Section: Local To Regional Scale Biogenic Voc Flux Measurements and Msupporting

confidence: 65%

Natural volatile organic compound emissions from plants and their roles in oxidant balance and particle formation

Longo¹,

Freitas²,

Andreae³

et al. 2009

Amazonia and Global Change

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Section: Local To Regional Scale Biogenic Voc Flux Measurements and Msupporting

confidence: 65%

Natural volatile organic compound emissions from plants and their roles in oxidant balance and particle formation

Longo¹,

Freitas²,

Andreae³

et al. 2009

Amazonia and Global Change

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“…Similar conclusions can be drawn from other work in this area. For example, global atmospheric chemistry models (ACMs) are not able to reconcile the observed isoprene concentrations with the measured isoprene emission rates; the emission rates incorporated tend to be lower than estimates based on direct emission measurements (Guenther, 2008). Higher emission rates in ACMs serve to dramatically deplete the OH radical concentration and lead to unrealistically high concentrations of certain key atmospheric constituents (Poisson et al, 2000;Bey et al, 2001) pointing to major uncertainties in the isoprene oxidation mechanism.…”

Section: Discussionmentioning

confidence: 99%

Quantifying the magnitude of a missing hydroxyl radical source in a tropical rainforest

et al. 2011

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Abstract. The lifetime of methane is controlled to a very large extent by the abundance of the OH radical. The tropics are a key region for methane removal, with oxidation in the lower tropical troposphere dominating the global methane removal budget (Bloss et al., 2005). In tropical forested environments where biogenic VOC emissions are high and NO x concentrations are low, OH concentrations are assumed to be low due to rapid reactions with sink species such as isoprene. New, simultaneous measurements of OH concentrations and OH reactivity, k OH , in a Borneo rainforest are reported and show much higher OH than predicted, with mean peak concentrations of ∼2.5×10 6 molecule cm −3 (10 min average) observed around solar noon. Whilst j (O 1 D) and humidity were high, low O 3 concentrations limited the OH production from O 3 photolysis. Measured OH reactivity was very high, peaking at a diurnal average of 29.1±8.5 s −1 , corresponding to an OH lifetime of only 34 ms. To maintain the observed OH concentration given the measured OH reactivity requires a rate of OH production approximately 10 times greater than calculated using all measured OH sources. A test of our current understanding of the chemistry within a tropical rainforest was made using a detailed zero-dimensional model to compare with measurements. The model overpredicted the observed HO 2 concentrations and significantly under-predicted OH concentrations. Inclusion of an additional OH source formed as a recycled product of OH iniCorrespondence to: L. K. Whalley (l.k.whalley@leeds.ac.uk) tiated isoprene oxidation improved the modelled OH agreement but only served to worsen the HO 2 model/measurement agreement. To replicate levels of both OH and HO 2 , a process that recycles HO 2 to OH is required; equivalent to the OH recycling effect of 0.74 ppbv of NO. This recycling step increases OH concentrations by 88 % at noon and has wide implications, leading to much higher predicted OH over tropical forests, with a concomitant reduction in the CH 4 lifetime and increase in the rate of VOC degradation.

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“…Thus, 3‐methylfuran has the potential to significantly contribute to the chemistry of the atmosphere due to the high emission rate of isoprene. Recent measurements of OH and HO 2 concentrations in high isoprene environments show significant discrepancies with model predictions, suggesting that the scientific understanding of the chemistry of isoprene oxidation is incomplete .…”

Section: Introductionmentioning

confidence: 99%

“…Thus, 3-methylfuran has the potential to significantly contribute to the chemistry of the atmosphere due to the high emission rate of isoprene. Recent measurements of OH and HO 2 concentrations in high isoprene environments show significant discrepancies with model predictions, suggesting that the scientific understanding of the chemistry of isoprene oxidation is incomplete [3][4][5][6][7][8][9][10]. Montzka et al [11] measured a daytime average 3-methylfuran mixing ratio of 60 ppt at a pine forest plantation in rural western Alabama with a daytime average NO x mixing ratio of approximately 1 ppb and an average isoprene mixing ratio of 2.8 ppb.…”

Section: Introductionmentioning

confidence: 99%

Measurements of the Kinetics of the Reaction of OH Radicals with 3‐Methylfuran at Low Pressure

Liljegren

Stevens

2013

Int J of Chemical Kinetics

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The rate constant for the reaction of OH with 3‐methylfuran was measured at 2, 4, and 6 Torr using discharge‐flow techniques coupled with laser‐induced fluorescence detection of OH. The measured rate constant (k) at 298 ± 2 K was (9.1 ± 0.3) × 10−11 cm3 molecule−1 s−1, where the quoted uncertainty reflects twice the standard error of the measurements. This result is in good agreement with previously reported relative rate constant measurements at atmospheric pressure and room temperature. An Arrhenius expression of k = (3.2 ± 0.4) × 10−11 e(310 ± 40)/T cm3 molecule−1 s−1 was determined from measurements of the rate constant between 273 and 368 K. The negative temperature dependence agrees with previously reported theoretical calculations for the reaction of OH with 3‐methylfuran and previously reported measurements of the temperature dependences of the rate constants for the reaction of OH with similar heterocyclic organics such as furan and thiophene.

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Are plant emissions green?

Cited by 18 publications

References 9 publications

Natural volatile organic compound emissions from plants and their roles in oxidant balance and particle formation

Natural volatile organic compound emissions from plants and their roles in oxidant balance and particle formation

Quantifying the magnitude of a missing hydroxyl radical source in a tropical rainforest

Measurements of the Kinetics of the Reaction of OH Radicals with 3‐Methylfuran at Low Pressure

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