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Isoprene suppression of new particle formation : Potential mechanisms and implications

Lee, Shan Hu; Uin, Janek; Guenther, Alex B.; de Gouw, Joost A.; Yu, Fangqun; Nadykto, Alex B.; Herb, Jason; Ng, Nga L.; Koss, Abigail and Brune, William Henry, et al. (2016) In Journal of Geophysical Research: Atmospheres 121(24). p.14-635
Abstract

Secondary aerosols formed from anthropogenic pollutants and natural emissions have substantial impacts on human health, air quality, and the Earth's climate. New particle formation (NPF) contributes up to 70% of the global production of cloud condensation nuclei (CCN), but the effects of biogenic volatile organic compounds (BVOCs) and their oxidation products on NPF processes in forests are poorly understood. Observations show that isoprene, the most abundant BVOC, suppresses NPF in forests. But the previously proposed chemical mechanism underlying this suppression process contradicts atmospheric observations. By reviewing observations made in other forests, it is clear that NPF rarely takes place during the summer when emissions of... (More)

Secondary aerosols formed from anthropogenic pollutants and natural emissions have substantial impacts on human health, air quality, and the Earth's climate. New particle formation (NPF) contributes up to 70% of the global production of cloud condensation nuclei (CCN), but the effects of biogenic volatile organic compounds (BVOCs) and their oxidation products on NPF processes in forests are poorly understood. Observations show that isoprene, the most abundant BVOC, suppresses NPF in forests. But the previously proposed chemical mechanism underlying this suppression process contradicts atmospheric observations. By reviewing observations made in other forests, it is clear that NPF rarely takes place during the summer when emissions of isoprene are high, even though there are sufficient concentrations of monoterpenes. But at present it is not clear how isoprene and its oxidation products may change the oxidation chemistry of terpenes and how NOx and other atmospheric key species affect NPF in forest environments. Future laboratory experiments with chemical speciation of gas phase nucleation precursors and clusters and chemical composition of particles smaller than 10 nm are required to understand the role of isoprene in NPF. Our results show that climate models can overpredict aerosol's first indirect effect when not considering the absence of NPF in the southeastern U.S. forests during the summer using the current nucleation algorithm that includes only sulfuric acid and total concentrations of low-volatility organic compounds. This highlights the importance of understanding NPF processes as function of temperature, relative humidity, and BVOC compositions to make valid predictions of NPF and CCN at a wide range of atmospheric conditions.

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published
subject
keywords
isoprene, monoterpene, new particle formation, nucleation, oxidation, suppression
in
Journal of Geophysical Research: Atmospheres
volume
121
issue
24
pages
15 pages
publisher
Wiley-Blackwell
external identifiers
  • scopus:85008516023
  • wos:000392247400020
ISSN
2169-897X
DOI
10.1002/2016JD024844
language
English
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yes
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bbad38ec-0386-406b-be6b-88ddeed6548b
date added to LUP
2017-02-01 08:38:13
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2017-09-18 11:34:54
@article{bbad38ec-0386-406b-be6b-88ddeed6548b,
  abstract     = {<p>Secondary aerosols formed from anthropogenic pollutants and natural emissions have substantial impacts on human health, air quality, and the Earth's climate. New particle formation (NPF) contributes up to 70% of the global production of cloud condensation nuclei (CCN), but the effects of biogenic volatile organic compounds (BVOCs) and their oxidation products on NPF processes in forests are poorly understood. Observations show that isoprene, the most abundant BVOC, suppresses NPF in forests. But the previously proposed chemical mechanism underlying this suppression process contradicts atmospheric observations. By reviewing observations made in other forests, it is clear that NPF rarely takes place during the summer when emissions of isoprene are high, even though there are sufficient concentrations of monoterpenes. But at present it is not clear how isoprene and its oxidation products may change the oxidation chemistry of terpenes and how NO<sub>x</sub> and other atmospheric key species affect NPF in forest environments. Future laboratory experiments with chemical speciation of gas phase nucleation precursors and clusters and chemical composition of particles smaller than 10 nm are required to understand the role of isoprene in NPF. Our results show that climate models can overpredict aerosol's first indirect effect when not considering the absence of NPF in the southeastern U.S. forests during the summer using the current nucleation algorithm that includes only sulfuric acid and total concentrations of low-volatility organic compounds. This highlights the importance of understanding NPF processes as function of temperature, relative humidity, and BVOC compositions to make valid predictions of NPF and CCN at a wide range of atmospheric conditions.</p>},
  author       = {Lee, Shan Hu and Uin, Janek and Guenther, Alex B. and de Gouw, Joost A. and Yu, Fangqun and Nadykto, Alex B. and Herb, Jason and Ng, Nga L. and Koss, Abigail and Brune, William Henry and Baumann, Karsten and Kanawade, Vijay P. and Keutsch, Frank N. and Nenes, Athanasios and Olsen, Kevin and Goldstein, Allen and Ouyang, Qi},
  issn         = {2169-897X},
  keyword      = {isoprene,monoterpene,new particle formation,nucleation,oxidation,suppression},
  language     = {eng},
  month        = {12},
  number       = {24},
  pages        = {14--635},
  publisher    = {Wiley-Blackwell},
  series       = {Journal of Geophysical Research: Atmospheres},
  title        = {Isoprene suppression of new particle formation : Potential mechanisms and implications},
  url          = {http://dx.doi.org/10.1002/2016JD024844},
  volume       = {121},
  year         = {2016},
}