scholarly journals Applying the Condensation Particle Counter Battery (CPCB) to study the water-affinity of freshly-formed 2–9 nm particles in boreal forest

2009 ◽  
Vol 9 (10) ◽  
pp. 3317-3330 ◽  
Author(s):  
I. Riipinen ◽  
H. E. Manninen ◽  
T. Yli-Juuti ◽  
M. Boy ◽  
M. Sipilä ◽  
...  
Keyword(s):  
Boreal Forest ◽  
Particle Formation ◽  
Water Soluble ◽  
Forest Site ◽  
Relative Role ◽  
Aerosol Formation ◽  
Particle Counter ◽  
Secondary Aerosol ◽  
Condensation Particle Counter ◽  
Water Affinity

Abstract. Measurements on the composition of nanometer-sized atmospheric particles are the key to understand which vapors participate in the secondary aerosol formation processes. Knowledge on these processes is crucial in assessing the climatic effects of secondary aerosol formation. We present data of >2 nm particle concentrations and their water-affinity measured with the Condensation Particle Counter Battery (CPCB) at a boreal forest site in Hyytiälä, Finland, during spring 2006. The data reveal that during new particle formation events, the smallest particles activate for growth at clearly smaller sizes in water than in butanol vapor. However, even at 2–4 nm, there are days when the particles seem to be less hygroscopic than ammonium sulfate or sulfuric acid, which are often referred to as the most likely compounds present in atmospheric nucleation. This observation points to the possible presence of water-soluble organics, even at the very first steps on particle formation. The water-affinity of the particles decreases with size, indicating that the vapors that participate in the first steps of the particle formation and growth are more hygroscopic than the vapors contributing to the later stages of the growth. This suggests that the relative role of less hygroscopic organics in atmospheric particle growth increases as a function of particle size.

scholarly journals Applying the CPCB setup to study the hygroscopicity and composition of freshly-formed 2–9 nm particles in boreal forest

2008 ◽  
Vol 8 (4) ◽  
pp. 14893-14925 ◽  
Author(s):  
I. Riipinen ◽  
H. E. Manninen ◽  
T. Yli-Juuti ◽  
M. Boy ◽  
M. Sipilä ◽  
...  
Keyword(s):  
Boreal Forest ◽  
Particle Growth ◽  
Particle Formation ◽  
Water Soluble ◽  
Forest Site ◽  
Relative Role ◽  
Aerosol Formation ◽  
Climatic Effects ◽  
Secondary Aerosol ◽  
Atmospheric Particle

Abstract. Measurements on the composition of nanometer-sized atmospheric particles are the key to understand which vapors participate in the secondary aerosol formation processes. Knowledge on these processes is crucial in assessing the climatic effects of secondary aerosol formation. We present data of >2 nm particle concentrations and their hygroscopicity measured with the Condensation Particle Counter Battery (CPCB) at a boreal forest site in Hyytiälä, Finland, during spring 2006. This is the first time such results on the hygroscopicity and composition of the freshly formed atmospheric clusters as small as 2 nm have been reported – bringing us closer to online measurements of the compounds participating in atmospheric particle formation. The data reveal that during new particle formation events, the smallest particles activate for growth at clearly smaller sizes in water than in butanol vapor. However, even at 2–4 nm, the particles are less hygroscopic than ammonium sulfate or sulfuric acid, which are often referred to as the most likely compounds present in atmospheric nucleation. This observation points to the presence of water-soluble organics, even at the very first steps on particle formation. The water-affinity of the particles decreases with size, indicating that the vapors that participate in the first steps of the particle formation and growth are more hygroscopic than the vapors contributing to the later stages of the growth. This suggests that the relative role of less hygroscopic organics in atmospheric particle growth increases as a function of particle size.

scholarly journals Modelling the formation of organic particles in the atmosphere

2003 ◽  
Vol 3 (6) ◽  
pp. 6147-6178 ◽  
Author(s):  
T. Anttila ◽  
V.-M. Kerminen ◽  
M. Kulmala ◽  
A. Laaksonen ◽  
C. O’Dowd
Keyword(s):  
Sulphuric Acid ◽  
Particle Formation ◽  
Water Soluble ◽  
Forest Site ◽  
Initial Growth ◽  
Aerosol Formation ◽  
Stable Clusters ◽  
Kohler Theory ◽  
Organic Particles ◽  
Organic Particle

Abstract. A modelling study investigating the formation of organic particles from inorganic, thermodynamically stable clusters was carried out. A recently-developed theory, the so-called nano-Köhler theory, which describes a thermodynamic equilibrium between a nanometer-size cluster, water and water-soluble organic compound, was implemented in a dynamical model along with a treatment of the appropriate aerosol and gas-phase processes. The obtained results suggest that both gaseous sulphuric acid and organic vapours contribute to organic particle formation. The initial growth of freshly-nucleated clusters having a diameter around 1 nm is driven by condensation of gaseous sulphuric acid and by a lesser extent cluster self-coagulation. After the clusters have reached sizes of around 2 nm in diameter, low-volatile organic vapours start to condense spontaneously into the clusters, thereby accelerating their growth to detectable sizes. A shortage of gaseous sulphuric acid or organic vapours limit, or suppress altogether, the particle formation, since freshly-nucleated clusters are rapidly coagulated away by pre-existing particles. The obtained modelling results were applied to explaining the observed seasonal cycle in the number of aerosol formation events in a continental forest site.

scholarly journals Particle concentration and flux dynamics in the atmospheric boundary layer as the indicator of formation mechanism

2011 ◽  
Vol 11 (12) ◽  
pp. 5591-5601 ◽  
Author(s):  
J. Lauros ◽  
A. Sogachev ◽  
S. Smolander ◽  
H. Vuollekoski ◽  
S.-L. Sihto ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Atmospheric Boundary Layer ◽  
Formation Mechanism ◽  
Turbulent Transport ◽  
Particle Formation ◽  
Formation Mechanisms ◽  
Forest Site ◽  
Aerosol Formation ◽  
Flux Dynamics ◽  
Layer Deposition

Abstract. We carried out column model simulations to study particle fluxes and deposition and to evaluate different particle formation mechanisms at a boreal forest site in Finland. We show that kinetic nucleation of sulphuric acid cannot be responsible for new particle formation alone as the simulated vertical profile of particle number concentration does not correspond to observations. Instead organic induced nucleation leads to good agreement confirming the relevance of the aerosol formation mechanism including organic compounds emitted by the biosphere. The simulation of aerosol concentration within the atmospheric boundary layer during nucleation event days shows a highly dynamical picture, where particle formation is coupled with chemistry and turbulent transport. We have demonstrated the suitability of our turbulent mixing scheme in reproducing the most important characteristics of particle dynamics within the boundary layer. Deposition and particle flux simulations show that deposition affects noticeably only the smallest particles in the lowest part of the atmospheric boundary layer.

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 The importance of sesquiterpene oxidation products for secondary organic aerosol formation in a spring-time hemi-boreal forest

2021 ◽  
Author(s):  
Luis M. F. Barreira ◽  
Arttu Ylisirniö ◽  
Iida Pullinen ◽  
Angela Buchholz ◽  
Zijun Li ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Boreal Forest ◽  
Organic Compounds ◽  
Field Experiments ◽  
Complex Mixture ◽  
Particle Formation ◽  
Oxidation Products ◽  
Ionization Mass ◽  
Particle Phase ◽  
Aerosol Formation

Abstract. Secondary organic aerosols (SOA) formed from biogenic volatile organic compounds (BVOCs) constitute a significant fraction of atmospheric particulate matter and have been recognized to affect significantly the climate and air quality. Many laboratory and field experiments have studied SOA particle formation and growth in the recent years. Most of them have focused on a few monoterpenes and isoprene. However, atmospheric SOA particulate mass yields and chemical composition result from a much more complex mixture of oxidation products originating from many BVOCs, including terpenes other than isoprene and monoterpenes. Thus, a large uncertainty still remains regarding the contribution of BVOCs to SOA. In particular, organic compounds formed from sesquiterpenes have not been thoroughly investigated, and their contribution to SOA remains poorly characterized. In this study, a Filter Inlet for Gases and Aerosols (FIGAERO) combined with a high-resolution time-of-flight chemical ionization mass spectrometer (CIMS), with iodide ionization, was used for the simultaneous measurement of gas and particle phase atmospheric SOA. The aim of the study was to evaluate the relative contribution of sesquiterpene oxidation products to SOA in a spring-time hemi-boreal forest environment. Our results revealed that monoterpene and sesquiterpene oxidation products were the main contributors to SOA particles. The chemical composition of SOA particles was compared for times when either monoterpene or sesquiterpene oxidation products were dominant and possible key oxidation products for SOA particle formation were identified. Surprisingly, sesquiterpene oxidation products were the predominant fraction in the particle phase at some periods, while their gas phase concentrations remained much lower than those of monoterpene products. This can be explained by quick and effective partitioning of sesquiterpene products into the particle phase or their efficient removal by dry deposition. The SOA particle volatility determined from measured thermograms increased when the concentration of sesquiterpene oxidation products in SOA particles was higher than that of monoterpenes. Overall, this study demonstrates the important role of sesquiterpenes in atmospheric chemistry and suggests that the contribution of their products to SOA particles is being underestimated in comparison to the most studied terpenes.

scholarly journals SO<sub>2</sub> and NH<sub>3</sub> emissions enhance organosulfur compounds and fine particle formation from the photooxidation of a typical aromatic hydrocarbon

2021 ◽  
Vol 21 (10) ◽  
pp. 7963-7981
Author(s):  
Zhaomin Yang ◽  
Li Xu ◽  
Narcisse T. Tsona ◽  
Jianlong Li ◽  
Xin Luo ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Oxidation Mechanism ◽  
Particle Formation ◽  
Urban Atmosphere ◽  
Mass Spectrometry Analysis ◽  
Formation Mechanisms ◽  
Chemical Compositions ◽  
Organosulfur Compounds ◽  
Aerosol Formation ◽  
Secondary Aerosol

Abstract. Aromatic hydrocarbons can dominate the volatile organic compound budget in the urban atmosphere. Among them, 1,2,4-trimethylbenzene (TMB), mainly emitted from solvent use, is one of the most important secondary organic aerosol (SOA) precursors. Although atmospheric SO2 and NH3 levels can affect secondary aerosol formation, the influenced extent of their impact and their detailed driving mechanisms are not well understood. The focus of the present study is to examine the chemical compositions and formation mechanisms of SOA from TMB photooxidation influenced by SO2 and/or NH3. Here, we show that SO2 emission could considerably enhance aerosol particle formation due to SO2-induced sulfate generation and acid-catalyzed heterogeneous reactions. Orbitrap mass spectrometry measurements revealed the generation of not only typical TMB products but also hitherto unidentified organosulfates (OSs) in SO2-added experiments. The OSs designated as being of unknown origin in earlier field measurements were also detected in TMB SOA, indicating that atmospheric OSs might also be originated from TMB photooxidation. For NH3-involved experiments, results demonstrated a positive correlation between NH3 levels and particle volume as well as number concentrations. The effects of NH3 on SOA composition were slight under SO2-free conditions but stronger in the presence of SO2. A series of multifunctional products with carbonyl, alcohols, and nitrate functional groups were tentatively characterized in NH3-involved experiments based on infrared spectra and mass spectrometry analysis. Plausible formation pathways were proposed for detected products in the particle phase. The volatility distributions of products, estimated using parameterization methods, suggested that the detected products gradually condense onto the nucleation particles to contribute to aerosol formation and growth. Our results suggest that strict control of SO2 and NH3 emissions might remarkably reduce organosulfates and secondary aerosol burden in the atmosphere. Updating the aromatic oxidation mechanism in models could result in more accurate treatment of particle formation for urban regions with considerable SO2, NH3, and aromatics emissions.

Biogenic Sesquiterpenes and Atmospheric New Particle Formation: A Boreal Forest Site Investigation

2007 ◽  
pp. 344-349 ◽  
Author(s):  
Michael Boy ◽  
Boris Bonn ◽  
Miikka Dal Maso ◽  
Hannele Hakola ◽  
Anne Hirsikko ◽  
...  
Keyword(s):  
Boreal Forest ◽  
Site Investigation ◽  
Particle Formation ◽  
Forest Site ◽  
New Particle Formation

Global observation of iodic acid (HIO3)

2020 ◽  
Author(s):  
Xucheng He ◽  
Tuija Jokinen ◽  
Nina Sarnela ◽  
Lisa Beck ◽  
Heikki Junninen ◽  
...  
Keyword(s):  
Atmospheric Chemistry ◽  
Cloud Condensation Nuclei ◽  
Particle Formation ◽  
Radiation Balance ◽  
Forest Site ◽  
Polar Regions ◽  
Aerosol Formation ◽  
Iodic Acid ◽  
Direct Role ◽  
Catalytic Ozone Destruction

&lt;p&gt;Trace iodine vapours have a significant impact on atmospheric chemistry, influencing catalytic ozone destruction and the HO&lt;sub&gt;x&lt;/sub&gt; / NO&lt;sub&gt;x&lt;/sub&gt; cycles. Oxidized iodine species also form aerosols in coastal and polar regions (O&amp;#8217;Dowd et al, 2002), playing a direct role in Earth&amp;#8217;s radiation balance. It was recently shown that iodic acid (HIO&lt;sub&gt;3&lt;/sub&gt;) has a significant impact on coastal new particle formation processes (Sipil&amp;#228; et al., 2016). However, neutral HIO&lt;sub&gt;3 &lt;/sub&gt;molecules have only been measured in two sites (Sipil&amp;#228; et al., 2016).&lt;/p&gt;&lt;p&gt;In this study, a global observation of HIO&lt;sub&gt;3&lt;/sub&gt; has been carried out in ten sites around the globe, including city sites, Arctic and Antarctica sites, a remote island site, a coastal site and a boreal forest site. While the existence of HIO&lt;sub&gt;3&lt;/sub&gt; is unambiguously revealed in all of the sites, its concentration varies significantly among them. Dedicated laboratory experiments are required to examine the particle formation rates from iodine-containing species to be able to predict their global importance in particle formation, and further, in cloud condensation nuclei formation.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;O&amp;#8217;Dowd, C. D. et al. Marine aerosol formation from biogenic iodine emissions. Nature &lt;strong&gt;417&lt;/strong&gt;, 632&amp;#8211;6 (2002)&lt;/p&gt;&lt;p&gt;Sipil&amp;#228;, M. et al. Molecular-scale evidence of aerosol particle formation via sequential addition of HIO&lt;sub&gt;3&lt;/sub&gt;. Nature &lt;strong&gt;537&lt;/strong&gt;, 532&amp;#8211;534 (2016).&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;

scholarly journals Size-resolved aerosol composition at an urban and a rural site in the Po Valley in summertime: implications for secondary aerosol formation

2016 ◽  
Author(s):  
S. Sandrini ◽  
D. van Pinxteren ◽  
L. Giulianelli ◽  
H. Herrmann ◽  
L. Poulain ◽  
...  
Keyword(s):  
Water Soluble ◽  
Photochemical Oxidation ◽  
Carbonaceous Aerosol ◽  
Rural Site ◽  
Urban Site ◽  
Aerosol Formation ◽  
Aerosol Composition ◽  
Accumulation Mode ◽  
Secondary Aerosol ◽  
Po Valley

Abstract. The aerosol size-segregated chemical composition was analyzed at an urban (Bologna) and a rural site (San Pietro Capofiume) in the Po Valley, Italy, during June and July 2012, to investigate sources and mechanisms of secondary aerosol formation during the summer. A significant enhancement of secondary organic and inorganic aerosol mass was observed under anticyclonic conditions with recirculation of planetary boundary layer air, but with substantial differences between the urban and the rural site. The data analysis, including a Principal Component Analysis (PCA) on the size-resolved dataset of chemical concentrations, indicated that the photochemical oxidation of inorganic and organic gaseous precursors was an important mechanism of secondary aerosol formation at both sites. In addition at the rural site a second formation process, explaining the largest fraction (22 %) of the total variance, was active at night-time, especially under stagnant conditions. Nocturnal chemistry in the rural Po Valley was associated with the formation of ammonium nitrate in large accumulation mode (0.42–1.2 µm) aerosols favored by local thermodynamic conditions (higher relative humidity and lower temperature compared to the urban site). Nocturnal concentrations of fine nitrate were, in fact, on average five times higher at the rural site than in Bologna. The water uptake by this highly hygroscopic compound under high RH conditions provided the medium for increased nocturnal aerosol uptake of water soluble organic gases and possibly also for aqueous chemistry, as revealed by the shifting of peak concentrations of secondary compounds (WSOC and sulfate) toward the large accumulation mode (0.42–1.2 µm). Contrarily, the diurnal production of WSOC (proxy for secondary organic aerosol) by photochemistry was similar at the two sites but mostly affected the small accumulation mode of particles (0.14–0.42 µm) in Bologna, while a shift to larger accumulation mode was observed at the rural site. A significant increment in carbonaceous aerosol concentration (for both WSOC and WINC) at the urban site was recorded mainly in the size range 0.05–0.14 µm indicating a direct influence of traffic emissions on the mass concentrations of quasi-ultrafine particles.

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