High Natural Aerosol Loading over Boreal Forests

Tunved, Peter; Hansson, H.‐C.; Kerminen, Veli‐Matti; Ström, Johan; Maso, Miikka Dal; Lihavainen, Heikki; Viisanen, Y.; Aalto, Pasi; Komppula, Mika; Kulmala, Markku

doi:10.1126/science.1123052

Cited by 480 publications

(448 citation statements)

References 22 publications

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“…The direct contribution of anthropogenic emissions to SOA is small, but anthropogenic aerosols may serve as nuclei for biogenic SOA formation and growth 42 . Recent work has shown that monoterpenes are the chief determinant of aerosol mass over boreal forests 43 , and that sesquiterpene oxidation products are crucial for the initial stages of particle formation 44 . The situation with isoprene is more complex: it has been recognized as an SOA precursor 45,35 , but isoprene has also been shown to suppress particle formation from monoterpenes, probably through competing reactions with OH (ref.…”

Section: From Gases To Particlesmentioning

confidence: 99%

Terrestrial biogeochemical feedbacks in the climate system

et al. 2010

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The terrestrial biosphere is a key regulator of atmospheric chemistry and climate. During past periods of climate change, vegetation cover and interactions between the terrestrial biosphere and atmosphere changed within decades. Modern observations show a similar responsiveness of terrestrial biogeochemistry to anthropogenically forced climate change and air pollution. Although interactions between the carbon cycle and climate have been a central focus, other biogeochemical feedbacks could be as important in modulating future climate change. Total positive radiative forcings resulting from feedbacks between the terrestrial biosphere and the atmosphere are estimated to reach up to 0.9 or 1.5 W m(-2) K-1 towards the end of the twenty-first century, depending on the extent to which interactions with the nitrogen cycle stimulate or limit carbon sequestration. This substantially reduces and potentially even eliminates the cooling effect owing to carbon dioxide fertilization of the terrestrial biota. The overall magnitude of the biogeochemical feedbacks could potentially be similar to that of feedbacks in the physical climate system, but there are large uncertainties in the magnitude of individual estimates and in accounting for synergies between these effects

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Section: From Gases To Particlesmentioning

confidence: 99%

Terrestrial biogeochemical feedbacks in the climate system

et al. 2010

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“…Subsequently, only the data relative to the four summer months from June to September were considered when calculating the long-term variations of AOD, with the background contribution hereafter referred to as BG, and enhancements attributed to extinction mainly by smoke particles from boreal forest fires (hereafter referred to as FFS) in North America and Siberia (Forster et al, 2001;Damoah et al, 2004;Stohl et al, 2006;Tunved et al, 2006). Following the same approach used by Tomasi et al (2007), this summer-time analysis ignores influences of AH and/or Asian dust (AD) that occur mainly during late winter and spring (Rahn et al, 1977;Shaw, 1982Shaw, , 1983VanCuren and Cahill, 2002;Stone et al, 2007;Quinn et al, 2007).…”

Section: Long-term Variations In Aerosol Optical Depth At Arctic Sitesmentioning

confidence: 99%

An update on polar aerosol optical properties using POLAR-AOD and other measurements performed during the International Polar Year

Tomasi

Lupi

Mazzola

et al. 2012

Atmospheric Environment

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“…Fuentes et al, 2000) and serve as precursors for secondary organic aerosols (SOA) (Hallquist et al, 2009). In regions with low pre-existing particulate matter, VOC oxidation can produce low volatile products which are involved in new particle formation (Tunved et al, 2006). Emissions of isoprene and monoterpenes (MT) from vegetation are well known and their dependence on parameters such as light intensity and temperature can be described semi-empirically (Guenther, 2007).…”

Section: Introductionmentioning

confidence: 99%

Isoprene in poplar emissions: effects on new particle formation and OH concentrations

Kiendler‐Scharr¹,

Andres²,

Bachner³

et al. 2012

Atmos. Chem. Phys.

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Abstract. Stress-induced volatile organic compound (VOC) emissions from transgenic Grey poplar modified in isoprene emission potential were used for the investigation of photochemical secondary organic aerosol (SOA) formation. In poplar, acute ozone stress induces the emission of a wide array of VOCs dominated by sesquiterpenes and aromatic VOCs. Constitutive light-dependent emission of isoprene ranged between 66 nmol m −2 s −1 in non-transgenic controls (wild type WT) and nearly zero (<0.5 nmol m −2 s −1 ) in isoprene emission-repressed plants (line RA22), respectively. Nucleation rates of up to 3600 cm −3 s −1 were observed in our experiments. In the presence of isoprene new particle formation was suppressed compared to non-isoprene containing VOC mixtures. Compared to isoprene/monoterpene systems emitted from other plants the suppression of nucleation by isoprene was less effective for the VOC mixture emitted from stressed poplar. This is explained by the observed high efficiency of new particle formation for emissions from stressed poplar. Direct measurements of OH in the reaction chamber revealed that the steady state concentration of OH is lower in the presence of isoprene than in the absence of isoprene, supporting the hypothesis that isoprenes' suppressing effect on nucleation is related to radical chemistry. In order to test whether isoprene contributes to SOA mass formation, fully deuterated isoprene (C 5 D 8 ) was added to the stress-induced emission profile of an isoprene free poplar mutant. Mass spectral analysis showed that, despite the isoprene-induced suppression of particle formation, fractions of deuterated isoprene were incorporated into the SOA. A fractional mass yield of 2.3 % of isoprene was observed. Future emission changes due to land use and climate change may therefore affect both gas phase oxidation capacity and new particle number formation.

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High Natural Aerosol Loading over Boreal Forests

Cited by 480 publications

References 22 publications

Terrestrial biogeochemical feedbacks in the climate system

Terrestrial biogeochemical feedbacks in the climate system

An update on polar aerosol optical properties using POLAR-AOD and other measurements performed during the International Polar Year

Isoprene in poplar emissions: effects on new particle formation and OH concentrations

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