TY  - JOUR
AU  - Kiendler-Scharr, A.
AU  - Wildt, J.
AU  - Dal Maso, M.
AU  - Hohaus, T.
AU  - Kleist, E.
AU  - Mentel, T. F.
AU  - Tillmann, R.
AU  - Uerlings, R.
AU  - Schurr, U.
AU  - Wahner, A.
TI  - New particle formation in forests inhibited  by isoprene emissions
JO  - Nature 
VL  - 461
SN  - 0028-0836
CY  - London [u.a.]
PB  - Nature Publising Group
M1  - PreJuSER-5759
SP  - 381 - 384
PY  - 2009
N1  - We gratefully acknowledge support by the European Commission (IP-EUCAARI, contract number 036833-2).
AB  - It has been suggested that volatile organic compounds (VOCs) are involved in organic aerosol formation, which in turn affects radiative forcing and climate. The most abundant VOCs emitted by terrestrial vegetation are isoprene and its derivatives, such as monoterpenes and sesquiterpenes. New particle formation in boreal regions is related to monoterpene emissions and causes an estimated negative radiative forcing of about -0.2 to -0.9 W m(-2). The annual variation in aerosol growth rates during particle nucleation events correlates with the seasonality of monoterpene emissions of the local vegetation, with a maximum during summer. The frequency of nucleation events peaks, however, in spring and autumn. Here we present evidence from simulation experiments conducted in a plant chamber that isoprene can significantly inhibit new particle formation. The process leading to the observed decrease in particle number concentration is linked to the high reactivity of isoprene with the hydroxyl radical (OH). The suppression is stronger with higher concentrations of isoprene, but with little dependence on the specific VOC mixture emitted by trees. A parameterization of the observed suppression factor as a function of isoprene concentration suggests that the number of new particles produced depends on the OH concentration and VOCs involved in the production of new particles undergo three to four steps of oxidation by OH. Our measurements simulate conditions that are typical for forested regions and may explain the observed seasonality in the frequency of aerosol nucleation events, with a lower number of nucleation events during summer compared to autumn and spring. Biogenic emissions of isoprene are controlled by temperature and light, and if the relative isoprene abundance of biogenic VOC emissions increases in response to climate change or land use change, the new particle formation potential may decrease, thus damping the aerosol negative radiative forcing effect.
KW  - Aerosols: analysis
KW  - Aerosols: metabolism
KW  - Air: analysis
KW  - Betula: drug effects
KW  - Betula: metabolism
KW  - Butadienes: analysis
KW  - Butadienes: pharmacology
KW  - Carbon: analysis
KW  - Environment, Controlled
KW  - Fagus: drug effects
KW  - Fagus: metabolism
KW  - Hemiterpenes: analysis
KW  - Hemiterpenes: pharmacology
KW  - Hemiterpenes: secretion
KW  - Hydroxyl Radical: analysis
KW  - Hydroxyl Radical: metabolism
KW  - Light
KW  - Monoterpenes: metabolism
KW  - Monoterpenes: pharmacology
KW  - Oxidation-Reduction
KW  - Pentanes: analysis
KW  - Pentanes: pharmacology
KW  - Picea: drug effects
KW  - Picea: metabolism
KW  - Seasons
KW  - Temperature
KW  - Time Factors
KW  - Trees: drug effects
KW  - Trees: metabolism
KW  - Volatile Organic Compounds: analysis
KW  - Volatile Organic Compounds: metabolism
KW  - Aerosols (NLM Chemicals)
KW  - Butadienes (NLM Chemicals)
KW  - Hemiterpenes (NLM Chemicals)
KW  - Monoterpenes (NLM Chemicals)
KW  - Pentanes (NLM Chemicals)
KW  - Volatile Organic Compounds (NLM Chemicals)
KW  - Hydroxyl Radical (NLM Chemicals)
KW  - Carbon (NLM Chemicals)
KW  - isoprene (NLM Chemicals)
KW  - J (WoSType)
LB  - PUB:(DE-HGF)16
C6  - pmid:19759617
UR  - <Go to ISI:>//WOS:000269828100036
DO  - DOI:10.1038/nature08292
UR  - https://juser.fz-juelich.de/record/5759
ER  -