Molecular identification of organic vapors driving atmospheric nanoparticle growth

Abstract Particles formed in the atmosphere via nucleation provide about half the number of atmospheric cloud condensation nuclei, but in many locations, this process is limited by the growth of the newly formed particles. That growth is often via condensation of organic vapors. Identification of these vapors and their sources is thus fundamental for simulating changes to aerosol-cloud interactions, which are one of the most uncertain aspects of anthropogenic climate forcing. Here we present direct molecular-level observations of a distribution of organic vapors in a forested environment that can explain simultaneously observed atmospheric nanoparticle growth from 3 to 50 nm. Furthermore, the volatility distribution of these vapors is sufficient to explain nanoparticle growth without invoking particle-phase processes. The agreement between observed mass growth, and the growth predicted from the observed mass of condensing vapors in a forested environment thus represents an important step forward in the characterization of atmospheric particle growth.

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Model for acid-base chemistry in nanoparticle growth (MABNAG)

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-13-7175-2013 ◽

2013 ◽

Vol 13 (3) ◽

pp. 7175-7222 ◽

Cited By ~ 1

Author(s):

T. Yli-Juuti ◽

K. Barsanti ◽

L. Hildebrandt Ruiz ◽

A.-J. Kieloaho ◽

U. Makkonen ◽

...

Keyword(s):

Particle Size ◽

Sulfuric Acid ◽

Gas Phase ◽

Organic Compounds ◽

Particle Growth ◽

Particle Phase ◽

Vapor Pressures ◽

Salt Formation ◽

Acid Base ◽

Nanoparticle Growth

Abstract. Climatic effects of newly-formed atmospheric secondary aerosol particles are to a large extent determined by their condensational growth rates. However, all the vapors condensing on atmospheric nanoparticles and growing them to climatically relevant sizes are not identified yet and the effects of particle phase processes on particle growth rates are poorly known. Besides sulfuric acid, organic compounds are known to contribute significantly to atmospheric nanoparticle growth. In this study a particle growth model MABNAG (Model for Acid-Base chemistry in NAnoparticle Growth) was developed to study the effect of salt formation on nanoparticle growth, which has been proposed as a potential mechanism lowering the equilibrium vapor pressures of organic compounds through dissociation in the particle phase and thus preventing their evaporation. MABNAG is a model for monodisperse aqueous particles and it couples dynamics of condensation to particle phase chemistry. Non-zero equilibrium vapor pressures, with both size and composition dependence, are considered for condensation. The model was applied for atmospherically relevant systems with sulfuric acid, one organic acid, ammonia, one amine and water in the gas phase allowed to condense on 3–20 nm particles. The effect of dissociation of the organic acid was found to be small under ambient conditions typical for a boreal forest site, but considerable for base-rich environments (gas phase concentrations of about 1010 cm−3 for the sum of the bases). The contribution of the bases to particle mass decreased as particle size increased, except at very high gas phase concentrations of the bases. The relative importance of amine versus ammonia did not change significantly as a function of particle size. While our results give a reasonable first estimate on the maximum contribution of salt formation to nanoparticle growth, further studies on, e.g. the thermodynamic properties of the atmospheric organics, concentrations of low-volatility organic acids and amines, along with studies investigating the applicability of thermodynamics for the smallest nanoparticles are needed to truly understand the acid-base chemistry of atmospheric nanoparticles.

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Model for acid-base chemistry in nanoparticle growth (MABNAG)

Atmospheric Chemistry and Physics ◽

10.5194/acp-13-12507-2013 ◽

2013 ◽

Vol 13 (24) ◽

pp. 12507-12524 ◽

Cited By ~ 32

Author(s):

T. Yli-Juuti ◽

K. Barsanti ◽

L. Hildebrandt Ruiz ◽

A.-J. Kieloaho ◽

U. Makkonen ◽

...

Keyword(s):

Particle Size ◽

Sulfuric Acid ◽

Gas Phase ◽

Organic Compounds ◽

Growth Rates ◽

Particle Growth ◽

Particle Phase ◽

Salt Formation ◽

Acid Base ◽

Nanoparticle Growth

Abstract. Climatic effects of newly-formed atmospheric secondary aerosol particles are to a large extent determined by their condensational growth rates. However, all the vapours condensing on atmospheric nanoparticles and growing them to climatically relevant sizes are not identified yet and the effects of particle phase processes on particle growth rates are poorly known. Besides sulfuric acid, organic compounds are known to contribute significantly to atmospheric nanoparticle growth. In this study a particle growth model MABNAG (Model for Acid-Base chemistry in NAnoparticle Growth) was developed to study the effect of salt formation on nanoparticle growth, which has been proposed as a potential mechanism lowering the equilibrium vapour pressures of organic compounds through dissociation in the particle phase and thus preventing their evaporation. MABNAG is a model for monodisperse aqueous particles and it couples dynamics of condensation to particle phase chemistry. Non-zero equilibrium vapour pressures, with both size and composition dependence, are considered for condensation. The model was applied for atmospherically relevant systems with sulfuric acid, one organic acid, ammonia, one amine and water in the gas phase allowed to condense on 3–20 nm particles. The effect of dissociation of the organic acid was found to be small under ambient conditions typical for a boreal forest site, but considerable for base-rich environments (gas phase concentrations of about 1010 cm−3 for the sum of the bases). The contribution of the bases to particle mass decreased as particle size increased, except at very high gas phase concentrations of the bases. The relative importance of amine versus ammonia did not change significantly as a function of particle size. While our results give a reasonable first estimate on the maximum contribution of salt formation to nanoparticle growth, further studies on, e.g. the thermodynamic properties of the atmospheric organics, concentrations of low-volatility organics and amines, along with studies investigating the applicability of thermodynamics for the smallest nanoparticles are needed to truly understand the acid-base chemistry of atmospheric nanoparticles.

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Characterization of aerosol growth events over Ellesmere Island during the summers of 2015 and 2016

10.5194/acp-2018-428 ◽

2018 ◽

Cited By ~ 2

Author(s):

Samantha Tremblay ◽

Jean-Christophe Picard ◽

Jill O. Bachelder ◽

Erik Lutsch ◽

Kimberly Strong ◽

...

Keyword(s):

Cloud Condensation Nuclei ◽

Particle Growth ◽

Temperature Inversion ◽

Nucleation And Growth ◽

Ellesmere Island ◽

The Arctic ◽

Particle Nucleation ◽

Particle Phase ◽

Aerosol Composition ◽

Aerosol Mass

Abstract. The occurrence of frequent aerosol nucleation and growth events in the Arctic during summertime may impact the region’s climate through increasing the number of cloud condensation nuclei in the Arctic atmosphere. Measurements of aerosol size distributions and aerosol composition were taken during the summers of 2015 and 2016 at Eureka and Alert on Ellesmere Island in Nunavut, Canada. The corresponding results provide a better understanding of the frequency and spatial extent of these nucleation and growth events as well as of the composition and sources of aerosol mass during particle growth. These events are observed beginning in June with the melting of the sea ice rather than with polar sunrise, which strongly suggests emissions from marine sources are the primary cause of the events. Frequent particle nucleation followed by growth occurs throughout the summer. Correlated particle growths events at the two sites, separated by 480 km, indicate conditions existing over such large scales play a key role in determining the timing and the characteristics of the events. In addition, aerosol mass spectrometry measurements are used to analyze the size-resolved chemical composition of aerosols during two selected growth events. It is found that particles with diameters smaller than 100 nm are predominately organic with only a small sulphate contribution. The oxidation of the organic fraction also changes with particle size with larger particles containing a greater fraction of organic acids relative to other non-acid oxygenates (e.g. alcohols or aldehydes). It is also observed that the relative amount of m / z 44 in the measured mass spectra increases during the growth events suggesting increases in organic acid concentrations in the particle phase. The nucleation and growth events at Eureka are observed most often when the temperature inversion between the sea and the measurement site (at 610 m a.s.l.) is non-existent or weak allowing presumably fresh marine emissions to be mixed upward to the observatory altitude. While the nature of the gaseous precursors responsible for the growth events are poorly understood, oxidation of dimethyl sulphide alone to produce particle phase sulphate or methanesulphonic acid is not consistent with the measured aerosol composition, suggesting the importance of condensation of other gas phase organic compounds for particle growth.

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Semi-empirical parameterization of size-dependent atmospheric nanoparticle growth in continental environments

Atmospheric Chemistry and Physics ◽

10.5194/acp-13-7665-2013 ◽

2013 ◽

Vol 13 (15) ◽

pp. 7665-7682 ◽

Cited By ~ 17

Author(s):

S. A. K. Häkkinen ◽

H. E. Manninen ◽

T. Yli-Juuti ◽

J. Merikanto ◽

M. K. Kajos ◽

...

Keyword(s):

Large Scale ◽

Cloud Condensation Nuclei ◽

Anthropogenic Pollution ◽

Particle Growth ◽

Oxidation Products ◽

Forest Site ◽

Nanoparticle Growth ◽

One Year ◽

20 Nm ◽

Semi Empirical

Abstract. The capability to accurately yet efficiently represent atmospheric nanoparticle growth by biogenic and anthropogenic secondary organics is a challenge for current atmospheric large-scale models. It is, however, crucial to predict nanoparticle growth accurately in order to reliably estimate the atmospheric cloud condensation nuclei (CCN) concentrations. In this work we introduce a simple semi-empirical parameterization for sub-20 nm particle growth that distributes secondary organics to the nanoparticles according to their size and is therefore able to reproduce particle growth observed in the atmosphere. The parameterization includes particle growth by sulfuric acid, secondary organics from monoterpene oxidation (SORGMT) and an additional condensable vapor of non-monoterpene organics ("background"). The performance of the proposed parameterization was investigated using ambient data on particle growth rates in three diameter ranges (1.5–3 nm, 3–7 nm and 7–20 nm). The growth rate data were acquired from particle/air ion number size distribution measurements at six continental sites over Europe. The longest time series of 7 yr (2003–2009) was obtained from a boreal forest site in Hyytiälä, Finland, while about one year of data (2008–2009) was used for the other stations. The extensive ambient measurements made it possible to test how well the parameterization captures the seasonal cycle observed in sub-20 nm particle growth and to determine the weighing factors for distributing the SORGMT for different sized particles as well as the background mass flux (concentration). Besides the monoterpene oxidation products, background organics with a concentration comparable to SORGMT, around 6 × 107 cm−3 (consistent with an additional global SOA yield of 100 Tg yr−1) was needed to reproduce the observed nanoparticle growth. Simulations with global models suggest that the "background" could be linked to secondary biogenic organics that are formed in the presence of anthropogenic pollution.

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Semi-empirical parameterization of size-dependent atmospheric nanoparticle growth in continental environments

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-13-8489-2013 ◽

2013 ◽

Vol 13 (3) ◽

pp. 8489-8535 ◽

Cited By ~ 1

Author(s):

S. A. K. Häkkinen ◽

H. E. Manninen ◽

T. Yli-Juuti ◽

J. Merikanto ◽

M. K. Kajos ◽

...

Keyword(s):

Large Scale ◽

Cloud Condensation Nuclei ◽

Anthropogenic Pollution ◽

Particle Growth ◽

Oxidation Products ◽

Forest Site ◽

Nanoparticle Growth ◽

One Year ◽

20 Nm ◽

Semi Empirical

Abstract. The capability to accurately yet efficiently represent atmospheric nanoparticle growth by biogenic and anthropogenic secondary organics is a challenge for current atmospheric large-scale models. It is, however, crucial to predict nanoparticle growth accurately in order to reliably estimate the atmospheric cloud condensation nuclei (CCN) concentrations. In this work we introduce a~simple semi-empirical parameterization for sub-20 nm particle growth that distributes secondary organics to the nanoparticles according to their size and is therefore able to reproduce particle growth observed in the atmosphere. The parameterization includes particle growth by sulfuric acid, secondary organics from monoterpene oxidation (SORGMT) and an additional condensable non-monoterpene organics ("background"). The performance of the proposed parameterization was investigated using ambient data on particle growth rates in three size ranges (1.5–3 nm, 3–7 nm and 7–20 nm). The growth rate data was acquired from particle/air ion number size distribution measurements at six continental sites over Europe. The longest time series of 7 yr (2003 to 2009) was obtained from a boreal forest site in Hyytiälä, Finland, while about one year of data (2008–2009) was used for the other stations. The extensive ambient measurements made it possible to test how well the parameterization captures the seasonal cycle observed in sub-20 nm particle growth and to determine the weighing factors for distributing the SORGMT for different sized particles as well as the background mass flux (/concentration). Besides the monoterpene oxidation products, background organics with a concentration comparable to SORGMT, around 6 × 107 cm−3 (consistent with an additional global SOA yield of 100 Tg yr−1) was needed to reproduce the observed nanoparticle growth. Simulations with global models suggest that the "background" could be linked to secondary biogenic organics that are formed in the presence of anthropogenic pollution.

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Effects of oligomerization and decomposition to the nanoparticle growth, a model study

10.5194/acp-2021-571 ◽

2021 ◽

Author(s):

Arto Heitto ◽

Kari Lehtinen ◽

Tuukka Petäjä ◽

Felipe Lopez-Hilfiker ◽

Joel A. Thornton ◽

...

Keyword(s):

Organic Molecules ◽

Reaction Rates ◽

Climate Impacts ◽

Basis Set ◽

Base Case ◽

Particle Phase ◽

Maximum Increase ◽

Organic Vapors ◽

Nanoparticle Growth ◽

Model Study

Abstract. The rate at which freshly formed secondary aerosol particles grow is an important factor in determining their climate impacts. The growth rate of atmospheric nanoparticles may be affected by particle phase oligomerization and decomposition of condensing organic molecules. We used Model for Oligomerization and Decomposition in Nanoparticle Growth (MODNAG) to investigate the potential atmospheric significance of these effects. This was done by conducting multiple simulations with varying reaction-related parameters (volatilities of the involved compounds and reaction rates) using both artificial and ambient measured gas phase concentrations of organic vapors to define the condensing vapors. While our study does not aim at providing information on any specific reaction, our results indicate that particle phase reactions have significant potential to affect the nanoparticle growth. In simulations where one-third of a volatility basis set bin was allowed to go through particle phase reactions the maximum increase in growth rates was 71 % and decrease 26 % compared to base case where no particle phase reactions were assumed to take place. These results highlight the importance of investigating and increasing our understanding of particle phase reactions.

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Molecular characterization of ultrafine particles using extractive electrospray time-of-flight mass spectrometry

Environmental Science: Atmospheres ◽

10.1039/d1ea00050k ◽

2021 ◽

Vol 1 (6) ◽

pp. 434-448

Author(s):

Mihnea Surdu ◽

Veronika Pospisilova ◽

Mao Xiao ◽

Mingyi Wang ◽

Bernhard Mentler ◽

...

Keyword(s):

Mass Spectrometry ◽

Real Time ◽

Molecular Characterization ◽

Ultrafine Particles ◽

Molecular Level ◽

Oxidation Products ◽

Particle Phase ◽

Flight Mass Spectrometry ◽

Phase Data

Using real-time simultaneous gas- and particle-phase data, the condensation of naphthalene and β-caryophyllene oxidation products on a molecular level is discussed.

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Effects of oligomerization and decomposition on the nanoparticle growth: a model study

Atmospheric Chemistry and Physics ◽

10.5194/acp-22-155-2022 ◽

2022 ◽

Vol 22 (1) ◽

pp. 155-171

Author(s):

Arto Heitto ◽

Kari Lehtinen ◽

Tuukka Petäjä ◽

Felipe Lopez-Hilfiker ◽

Joel A. Thornton ◽

...

Keyword(s):

Organic Molecules ◽

Reaction Rates ◽

Climate Impacts ◽

Basis Set ◽

Base Case ◽

Particle Phase ◽

Maximum Increase ◽

Organic Vapors ◽

Nanoparticle Growth ◽

Model Study

Abstract. The rate at which freshly formed secondary aerosol particles grow is an important factor in determining their climate impacts. The growth rate of atmospheric nanoparticles may be affected by particle-phase oligomerization and decomposition of condensing organic molecules. We used the Model for Oligomerization and Decomposition in Nanoparticle Growth (MODNAG) to investigate the potential atmospheric significance of these effects. This was done by conducting multiple simulations with varying reaction-related parameters (volatilities of the involved compounds and reaction rates) using both artificial and ambient measured gas-phase concentrations of organic vapors to define the condensing vapors. While our study does not aim at providing information on any specific reaction, our results indicate that particle-phase reactions have significant potential to affect the nanoparticle growth. In simulations in which one-third of a volatility basis set bin was allowed to go through particle-phase reactions, the maximum increase in growth rates was 71 % and the decrease 26 % compared to the base case in which no particle-phase reactions were assumed to take place. These results highlight the importance of investigating and increasing our understanding of particle-phase reactions.

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