New Particle Formation and Growth in an Isoprene-Dominated Ozark Forest: From Sub-5 nm to CCN-Active Sizes

Yu, Huan; Ortega, John; Smith, James N.; Kanawade, Vijay P.; You, Yi; Liu, Yiying; Hosman, Kevin P.; Karl, T.; Seco, Roger; Geron, Chris; Pallardy, Stephen G.; Gu, Lianhong; Mikkilä, Jyri; Lee, Shan‐Hu

doi:10.1080/02786826.2014.984801

Cited by 52 publications

(39 citation statements)

References 80 publications

(84 reference statements)

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“…J 1.5 ranged from 10 −2 to 0.8 cm −3 s −1 and strongly correlated with the measured sulfuric acid concentration. These results are consistent with previous observations in the U.S. that sub‐2 nm particles exist only in the presence of sulfuric acid [ Yu et al ., 2013; Yu et al ., ]. However, our results contrast with the reports from the Hyytiälä boreal forest, where a constant pool of sub‐2 nm particles was observed during the day and night independent of sulfuric acid concentration [ Kulmala et al ., ].…”

Section: Resultsmentioning

confidence: 99%

Isoprene suppression of new particle formation: Potential mechanisms and implications

et al. 2016

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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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Section: Resultsmentioning

confidence: 99%

Isoprene suppression of new particle formation: Potential mechanisms and implications

et al. 2016

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“…High isoprene emission fluxes and mixing ratios during most of the measurement campaign played a potentially major role in atmospheric chemistry at this site. Monoterpenes, which had lower emission fluxes but have higher aerosol yields, contributed to atmospheric particle growth along with isoprene (Yu et al, 2014). Maximum isoprene fluxes measured at this Missouri forest during this study in 2012 (35.4 mg m À2 h À1 ) and in 2011 by Potosnak et al (2014;53.3 mg m À2 h À1 ) are the highest ever reported for a forest canopy, surpassing fluxes of up to 30 mg m À2 h À1 previously reported from an oil palm plantation in Borneo (Misztal et al, 2011).…”

Section: Voc Measurements In Contextmentioning

confidence: 99%

Ecosystem‐scale volatile organic compound fluxes during an extreme drought in a broadleaf temperate forest of the Missouri Ozarks (central USA)

Seco¹,

Karl

Guenther

et al. 2015

Global Change Biology

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Considerable amounts and varieties of biogenic volatile organic compounds (BVOCs) are exchanged between vegetation and the surrounding air. These BVOCs play key ecological and atmospheric roles that must be adequately represented for accurately modeling the coupled biosphere-atmosphere-climate earth system. One key uncertainty in existing models is the response of BVOC fluxes to an important global change process: drought. We describe the diurnal and seasonal variation in isoprene, monoterpene, and methanol fluxes from a temperate forest ecosystem before, during, and after an extreme 2012 drought event in the Ozark region of the central USA. BVOC fluxes were dominated by isoprene, which attained high emission rates of up to 35.4 mg m À2 h À1 at midday. Methanol fluxes were characterized by net deposition in the morning, changing to a net emission flux through the rest of the daylight hours. Net flux of CO 2 reached its seasonal maximum approximately a month earlier than isoprenoid fluxes, which highlights the differential response of photosynthesis and isoprenoid emissions to progressing drought conditions. Nevertheless, both processes were strongly suppressed under extreme drought, although isoprene fluxes remained relatively high compared to reported fluxes from other ecosystems. Methanol exchange was less affected by drought throughout the season, confirming the complex processes driving biogenic methanol fluxes. The fraction of daytime (7-17 h) assimilated carbon released back to the atmosphere combining the three BVOCs measured was 2% of gross primary productivity (GPP) and 4.9% of net ecosystem exchange (NEE) on average for our whole measurement campaign, while exceeding 5% of GPP and 10% of NEE just before the strongest drought phase. The MEGANv2.1 model correctly predicted diurnal variations in fluxes driven mainly by light and temperature, although further research is needed to address model BVOC fluxes during drought events.

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“…Both laboratory (Kirkby et al, ; Riccobono et al, ; Tröstl et al, ; Zhao et al, ) and field (Bianchi et al, ) studies have revealed the role of oxidized organic vapors in the nucleation and initial particle growth. Other studies have reported the contributions of the condensation of low volatility biogenic organic vapors to the growth of newly formed particles in the CCN size range (e.g., Yu et al, ; Zhou et al, ). In Amazon, where new particle formation (NPF) events were only observed in the wet season in an open pasture site (Wimmer et al, ), the enhancement of the solute mass is expected to be the main mechanism through which BSOA contribute to CCN number concentrations.…”

Section: Introductionmentioning

confidence: 99%

Hygroscopicity of Organic Aerosols and Their Contributions to CCN Concentrations Over a Midlatitude Forest in Japan

et al. 2018

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The formation of biogenic secondary organic aerosols (BSOAs) in forest environments is potentially important to cloud formation via changes of the cloud condensation nuclei (CCN) activity of aerosols. In this study, the CCN activation of submicrometer aerosols and their chemical compositions and size distributions were measured at a midlatitude forest site in Japan during the summer of 2014 to assess the hygroscopicity of the organic aerosols and their contributions to the local CCN concentrations. The mean number concentrations of the condensation nuclei and CCN at supersaturation (SS) conditions of 0.11–0.80% were 1,238 and 166–740 cm−3, respectively. Organic aerosols and sulfate dominated the submicrometer aerosol mass concentrations. The particle hygroscopicity increased with increases in particle diameters. The hygroscopicity parameter for the organics, κorg, was positively correlated with the atomic O to C ratio. The product of κorg and the volume fraction of OA was 0.12, accounting for 38% of the water uptake by aerosol particles. The hygroscopicity parameter of the locally formed fresh BSOA was estimated to be 0.09. The contribution of OA to the CCN number concentration, which was assessed by subtracting the CCN concentration of the hypothetical inorganic aerosols from that of the ambient aerosols, was 50–182 cm−3 for the SS range of 0.11–0.80%. The increase of the CCN number concentrations per 1‐μg/m3 increase of the BSOA was 23–299 cm−3 at 0.11–0.80% SS. The contribution of the BSOA to the CCN number concentration can be enhanced by new particle formation.

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New Particle Formation and Growth in an Isoprene-Dominated Ozark Forest: From Sub-5 nm to CCN-Active Sizes

Cited by 52 publications

References 80 publications

Isoprene suppression of new particle formation: Potential mechanisms and implications

Isoprene suppression of new particle formation: Potential mechanisms and implications

Ecosystem‐scale volatile organic compound fluxes during an extreme drought in a broadleaf temperate forest of the Missouri Ozarks (central USA)

Hygroscopicity of Organic Aerosols and Their Contributions to CCN Concentrations Over a Midlatitude Forest in Japan

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