Supplementary material to "Frequent new particle formation at remote sites in the temperate/boreal forest of North America"

2021 ◽  
Author(s):  
Meinrat O. Andreae ◽  
Tracey W. Andreae ◽  
Florian Ditas
Keyword(s):  
North America ◽  
Boreal Forest ◽  
Particle Formation ◽  
New Particle Formation ◽  
Remote Sites ◽  
Supplementary Material

scholarly journals Frequent new particle formation at remote sites in the temperate/boreal forest of North America

2021 ◽  
Author(s):  
Meinrat O. Andreae ◽  
Tracey W. Andreae ◽  
Florian Ditas
Keyword(s):  
North America ◽  
Boreal Forest ◽  
Forest Cover ◽  
Particle Formation ◽  
New Particle Formation ◽  
Nucleation Mode ◽  
North American Continent ◽  
The North ◽  
Forest Regions ◽  
Remote Sites

Abstract. The frequency and intensity of new particle formation (NPF) over remote forest regions in the temperate and boreal zones, and thus the importance of NPF for the aerosol budget and life cycle in the pristine atmosphere, remains controversial. Whereas NPF has been shown to occur relatively frequently at several sites in Scandinavia, it was found to be nearly absent at a mid-continental site in Siberia. To explore this issue further, we made measurements of aerosol size distributions between 10 and 420 nm diameter at two remote sites in the transition region between temperate and boreal forest in British Columbia, Canada. The measurements covered 23 days during the month of June 2019, at the time when NPF typically reaches its seasonal maximum in remote mid-latitude regions. These are the first such measurements in a near-pristine region on the North American continent. Although the sites were only 150 km apart, there were dramatic differences in NPF frequency and intensity between them. At the Eagle Lake site, NPF occurred daily and nucleation mode particle concentrations reached above 5000 cm−3. In contrast, at the Nazko River site, there were only 6 NPF events in 11 days and nucleation mode particle concentrations reached only about 800 cm−3. The reasons for this difference could not be conclusively resolved with the available data; they may include airmass origins, pre-existing aerosols, and the density and type of forest cover in the surrounding regions. Our results suggest that measurement campaigns in the remote forest regions of North America to investigate the role of NPF with a more comprehensive set of instrumentation are essential for a deeper scientific understanding of this important process.

scholarly journals Modelling studies of HOMs and their contributions to new particle formation and growth: comparison of boreal forest in Finland and a polluted environment in China

2018 ◽  
Vol 18 (16) ◽  
pp. 11779-11791 ◽  
Author(s):  
Ximeng Qi ◽  
Aijun Ding ◽  
Pontus Roldin ◽  
Zhengning Xu ◽  
Putian Zhou ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Boreal Forest ◽  
Environmental Conditions ◽  
Eastern China ◽  
Particle Growth ◽  
Particle Formation ◽  
Forest Site ◽  
Polluted Environment ◽  
New Particle Formation ◽  
Multifunctional Compounds

Abstract. Highly oxygenated multifunctional compounds (HOMs) play a key role in new particle formation (NPF), but their quantitative roles in different environments of the globe have not been well studied yet. Frequent NPF events were observed at two “flagship” stations under different environmental conditions, i.e. a remote boreal forest site (SMEAR II) in Finland and a suburban site (SORPES) in polluted eastern China. The averaged formation rate of 6 nm particles and the growth rate of 6–30 nm particles were 0.3 cm−3 s−1 and 4.5 nm h−1 at SMEAR II compared to 2.3 cm−3 s−1 and 8.7 nm h−1 at SORPES, respectively. To explore the differences of NPF at the two stations, the HOM concentrations and NPF events at two sites were simulated with the MALTE-BOX model, and their roles in NPF and particle growth in the two distinctly different environments are discussed. The model provides an acceptable agreement between the simulated and measured concentrations of sulfuric acid and HOMs at SMEAR II. The sulfuric acid and HOM organonitrate concentrations are significantly higher but other HOM monomers and dimers from monoterpene oxidation are lower at SORPES compared to SMEAR II. The model simulates the NPF events at SMEAR II with a good agreement but underestimates the growth of new particles at SORPES, indicating a dominant role of anthropogenic processes in the polluted environment. HOMs from monoterpene oxidation dominate the growth of ultrafine particles at SMEAR II while sulfuric acid and HOMs from aromatics oxidation play a more important role in particle growth. This study highlights the distinct roles of sulfuric acid and HOMs in NPF and particle growth in different environmental conditions and suggests the need for molecular-scale measurements in improving the understanding of NPF mechanisms in polluted areas like eastern China.

scholarly journals Hygroscopic properties of ultrafine aerosol particles in the boreal forest: diurnal variation, solubility and the influence of sulfuric acid

2007 ◽  
Vol 7 (1) ◽  
pp. 211-222 ◽  
Author(s):  
M. Ehn ◽  
T. Petäjä ◽  
H. Aufmhoff ◽  
P. Aalto ◽  
K. Hämeri ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Boreal Forest ◽  
Diurnal Variation ◽  
Gas Phase ◽  
Aerosol Particles ◽  
Particle Formation ◽  
Time Of Day ◽  
New Particle Formation ◽  
Hygroscopic Growth ◽  
Hygroscopic Properties

Abstract. The hygroscopic growth of aerosol particles present in a boreal forest was measured at a relative humidity of 88%. Simultaneously the gas phase concentration of sulfuric acid, a very hygroscopic compound, was monitored. The focus was mainly on days with new particle formation by nucleation. The measured hygroscopic growth factors (GF) correlated positively with the gaseous phase sulfuric acid concentrations. The smaller the particles, the stronger the correlation, with r=0.20 for 50 nm and r=0.50 for 10 nm particles. The increase in GF due to condensing sulfuric acid is expected to be larger for particles with initially smaller masses. During new particle formation, the changes in solubility of the new particles were calculated during their growth to Aitken mode sizes. As the modal diameter increased, the solubility of the particles decreased. This indicated that the initial particle growth was due to more hygroscopic compounds, whereas the later growth during the evening and night was mainly caused by less hygroscopic or even hydrophobic compounds. For all the measured sizes, a diurnal variation in GF was observed both during days with and without particle formation. The GF was lowest at around midnight, with a mean value of 1.12–1.24 depending on particle size and if new particle formation occurred during the day, and increased to 1.25–1.34 around noon. This can be tentatively explained by day- and nighttime gas-phase chemistry; different vapors will be present depending on the time of day, and through condensation these compounds will alter the hygroscopic properties of the particles in different ways.

Cluster dynamics in different environments: from the boreal forest to megacities

2020 ◽  
Author(s):  
Dominik Stolzenburg ◽  
Runlong Cai ◽  
Lauri Ahonen ◽  
Tiia Laurila ◽  
Sebastian Holm ◽  
...  
Keyword(s):  
Growth Rate ◽  
Boreal Forest ◽  
Measurement Errors ◽  
Global Analysis ◽  
Chem Phys ◽  
Particle Formation ◽  
Aerosol Size Distribution ◽  
Urban Site ◽  
New Particle Formation ◽  
Rate Analysis

<p>New particle formation (NPF) by gas-to-particle conversion occurs frequently in many different environments around the globe (Nieminen et al., 2018). NPF is the major contributor to the global cloud condensation nuclei budget (Gordon et al., 2017) and also impacts urban air quality (Guo et al., 2014). It is therefore crucial to understand how the newly formed particles can survive and grow to larger particles under different environmental conditions. Depending on the environment different condensable vapours and also different aerosol dynamics govern the NPF process.</p><p>In order to investigate the dynamics of aerosol growth in the sub-10 nm regime, where the newly formed particles are most vulnerable for losses to pre-existing aerosol, we tested several combining instrument inversion approaches. This allows to combine the measurements of several different particle sizing instruments in the sub-10 nm range, where each instrument offers different benefits and weaknesses. If the instruments are combined during the inversion, this could significantly reduce the error of the inferred particle size-distributions. Model results show that the regularization approach proposed by Wolfenbarger and Seinfeld (1990) yield the most stable inversion for data heavily influenced by measurement errors.</p><p>We than apply the tested inversion techniques to measurements in three different environments where an array of different state-of-the-art sub-10 nm sizing instruments was deployed: The SMEAR-II station in Hyytiälä, Finland, representative for a rural boreal forest background site, the SMEAR-III station in Helsinki, Finland, representative for a medium-polluted middle-scale European city, and at the Beijing University of Chemical Technology, China, an urban site in a global megacity.</p><p>We demonstrate that the combining instrument approach can enable a more detailed analysis of the cluster dynamics, e.g. by the application of size- and time resolving growth rate analysis tools (Pichelstorfer et al., 2018). This will lead to a better understanding of the role of coagulation and condensation in the particle growth process and will help to explain the different dynamics which lead to NPF in fundamentally different environments.</p><p><strong>References:</strong></p><p>Gordon, H. et al.: Causes and importance of new particle formation in the present-day and preindustrial atmospheres, J. Geophys. Res.-Atmos., 122, doi:10.1002/2017JD026844, 2017.</p><p>Guo, S. et al.: Elucidating severe urban haze formation in China, P. Nat. Acad. Sci. USA, 111(49), 17373 LP – 17378, doi:10.1073/pnas.1419604111, 2014.</p><p>Nieminen, T. et al.: Global analysis of continental boundary layer new particle formation based on long-term measurements, Atmos. Chem. Phys., (April), 1–34, doi:10.5194/acp-2018-304, 2018.</p><p>Pichelstorfer, L et al.: Resolving nanoparticle growth mechanisms from size- and time-dependent growth rate analysis, Atmos. Chem. Phys., 18(2), 1307–1323, doi:10.5194/acp-18-1307-2018, 2018.</p><p>Wolfenbarger, J. K. and Seinfeld, J. H.: Inversion of aerosol size distribution data, J. Aerosol Sci., 21(2), 227–247, doi:https://doi.org/10.1016/0021-8502(90)90007-K, 1990.</p>

scholarly journals Nanoparticles in boreal forest and coastal environment: a comparison of observations and implications of the nucleation mechanism

2009 ◽  
Vol 9 (6) ◽  
pp. 26627-26651 ◽  
Author(s):  
K. Lehtipalo ◽  
M. Kulmala ◽  
M. Sipilä ◽  
T. Petäjä ◽  
M. Vana ◽  
...  
Keyword(s):  
Boreal Forest ◽  
Pulse Height ◽  
Particle Formation ◽  
Coastal Environment ◽  
Nucleation Mechanism ◽  
Limiting Factor ◽  
Size Distributions ◽  
New Particle Formation ◽  
Particle Size Distributions ◽  
Large Molecules

Abstract. The detailed mechanism of secondary new particle formation in the atmosphere is still under debate. It is proposed that particle formation happens via activation of 1–2 nm atmospheric neutral molecular clusters and/or large molecules. Since traditional instrumentation does not reach these sizes, the hypothesis has not yet been verified. By directly measuring particle size distributions down to mobility diameters of about 1.3 nm with a pulse-height CPC we provide evidence of the nucleation mechanism in coastal environment (Mace Head, Ireland) and in boreal forest (Hyytiälä, Finland). In both places neutral sub-3 nm condensation nuclei (nano-CN) were continuously present, even when no new particle formation was detected. In Mace Head, however, the concentration of the nano-CN was far too low to account for the particle formation rates during particle bursts. Thus the results imply that on coastal sites new particle formation initiates, as proposed earlier, via homogenous nucleation from biogenic iodine vapors. In contrary, activation of pre-existing nano-CN remains a possible explanation in the boreal forest, but the observed concentrations are not the limiting factor for the particle formation events.

scholarly journals Supplementary material to "Molecular Insights into New Particle Formation in Barcelona, Spain"

2020 ◽  
Author(s):  
James Brean ◽  
David C. S. Beddows ◽  
Zongbo Shi ◽  
Brice Temime-Roussel ◽  
Nicolas Marchand ◽  
...  
Keyword(s):  
Particle Formation ◽  
New Particle Formation ◽  
Supplementary Material
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