The potential mechanism of atmospheric new particle formation involving amino acids with multiple functional groups

2021 ◽  
Author(s):  
Jiarong Liu ◽  
Ling Liu ◽  
Hui Rong ◽  
Xiuhui Zhang
Keyword(s):  
Amino Acids ◽  
Aspartic Acid ◽  
Functional Groups ◽  
Atmospheric Aerosols ◽  
Potential Role ◽  
Particle Formation ◽  
Potential Mechanism ◽  
New Particle Formation

Amino acids are recognized as significant components of atmospheric aerosols. However, its potential role in the atmospheric new particle formation (NPF) is poorly understood, especially aspartic acid (ASP), one of...

scholarly journals Growth of atmospheric nano-particles by heterogeneous nucleation of organic vapor

2013 ◽  
Vol 13 (13) ◽  
pp. 6523-6531 ◽  
Author(s):  
J. Wang ◽  
R. L. McGraw ◽  
C. Kuang
Keyword(s):  
Atmospheric Aerosols ◽  
Heterogeneous Nucleation ◽  
Particle Formation ◽  
Nano Particles ◽  
High Rate ◽  
Vapor Concentration ◽  
Strong Increase ◽  
Initial Growth ◽  
New Particle Formation ◽  
Cluster Number

Abstract. Atmospheric aerosols play critical roles in air quality, public health, and visibility. In addition, they strongly influence climate by scattering solar radiation and by changing the reflectivity and lifetime of clouds. One major but still poorly understood source of atmospheric aerosols is new particle formation, which consists of the formation of thermodynamically stable clusters from trace gas molecules (homogeneous nucleation) followed by growth of these clusters to a detectable size (~3 nm). Because freshly nucleated clusters are most susceptible to loss due to high rate of coagulation with pre-existing aerosol population, the initial growth rate strongly influences the rate of new particle formation and ambient aerosol population. Whereas many field observations and modeling studies indicate that organics enhance the initial growth of the clusters and therefore new particle formation, thermodynamic considerations would suggest that the strong increase of equilibrium vapor concentration due to cluster surface curvature (Kelvin effect) may prevent ambient organics from condensing on these small clusters. Here, the contribution of organics to the initial cluster growth is described as heterogeneous nucleation of organic molecules onto these clusters. We find that the strong gradient in cluster population with respect to its size leads to positive cluster number flux. This positive flux drives the growth of clusters substantially smaller than the Kelvin diameter, conventionally considered the minimum particle size that can be grown through condensation. The conventional approach neglects the contribution from the cluster concentration gradient, and underestimates the cluster survival probabilities by a factor of up to 60 if early growth of clusters is due to both condensation of sulfuric acid and heterogeneous nucleation of organic vapors.

scholarly journals Flux induced growth of atmospheric nano-particles by organic vapors

2012 ◽  
Vol 12 (9) ◽  
pp. 22813-22833 ◽  
Author(s):  
J. Wang ◽  
R. L. McGraw ◽  
C. Kuang
Keyword(s):  
Atmospheric Aerosols ◽  
Particle Formation ◽  
Nano Particles ◽  
High Rate ◽  
Vapor Concentration ◽  
Strong Increase ◽  
Initial Growth ◽  
New Particle Formation ◽  
Cluster Number ◽  
Condensational Growth

Abstract. Atmospheric aerosols play critical roles in air quality, public health, and visibility. In addition, they strongly influence climate by scattering solar radiation and by changing the reflectivity and lifetime of clouds. One major but still poorly understood source of atmospheric aerosol is new particle formation, which consists of the formation of thermodynamically stable clusters from trace gas molecules (homogeneous nucleation) followed by growth of these clusters to a detectable size (~3 nm). Because freshly nucleated clusters are most susceptible to loss due to high rate of coagulation with pre-existing aerosol population, the initial growth rate strongly influences the rate of new particle formation and ambient aerosol population. Whereas many field observations and modeling studies indicate that organics enhance the initial growth of the clusters and therefore new particle formation, thermodynamic considerations would suggest that the strong increase of equilibrium vapor concentration due to cluster surface curvature (Kelvin effect) may prevent ambient organics from condensing on these small clusters. Here the initial condensational growth of freshly nucleated clusters is described as heterogeneous nucleation of organic molecules onto these clusters. We find that the strong gradient in cluster population with respect to its size lead to positive cluster number flux, and therefore driving the growth of clusters substantially smaller than the Kelvin diameter, conventionally considered as the minimum particle size that can be grown through condensation. The conventional approach neglects this contribution from the cluster concentration gradient, and underestimates the rate of new particle formation by a factor of up to 60.

scholarly journals Molecular understanding of new-particle formation from alpha-pinene between −50 °C and 25 °C

2020 ◽  
Author(s):  
Mario Simon ◽  
Lubna Dada ◽  
Martin Heinritzi ◽  
Wiebke Scholz ◽  
Dominik Stolzenburg ◽  
...  
Keyword(s):  
Oxidation State ◽  
Atmospheric Aerosols ◽  
Particle Formation ◽  
Oxidation Products ◽  
Basis Set ◽  
Ionization Mass ◽  
Vapor Pressures ◽  
New Particle Formation ◽  
Wide Range ◽  
Earth’S Climate

Abstract. Highly-oxygenated organic molecules (HOMs) contribute substantially to the formation and growth of atmospheric aerosol particles, which affect air quality, human health and Earth's climate. HOMs are formed by rapid, gas-phase autoxidation of volatile organic compounds (VOCs) such as α-pinene, the most abundant monoterpene in the atmosphere. Due to their abundance and low volatility, HOMs can play an important role for new-particle formation (NPF) and the early growth of atmospheric aerosols, even without any further assistance of other low-volatility compounds such as sulfuric acid. Both the autoxidation reaction forming HOMs and their new-particle formation rates are expected to be strongly dependent on temperature. However, experimental data on both effects are limited. Dedicated experiments were performed at the CLOUD (Cosmics Leaving OUtdoor Droplets) chamber at CERN to address this question. In this study, we show that a decrease in temperature (from +25 to −50 °C) results in a reduced HOM yield and reduced oxidation state of the products, whereas the new-particle formation rates (J1.7 nm) increase substantially. Measurements with two different chemical ionization mass spectrometers (using nitrate and protonated water as reagent ion, respectively) provide the molecular composition of the gaseous oxidation products and a 2-dimensional volatility basis set model (2D-VBS) provides their volatility distribution. The HOM yield decreases with temperature from 6.2 % at 25 °C to 0.7 % at −50 °C. However, there is a strong reduction of the saturation vapor pressure of each oxidation state as the temperature is reduced. Overall, the reduction in volatility with temperature leads to an increase in the nucleation rates by up to three orders of magnitude at −50 °C compared with 25 °C. In addition, the enhancement of the nucleation rates by ions decreases with decreasing temperature, since the neutral molecular clusters have increased stability against evaporation. The resulting data quantify how the interplay between the temperature-dependent oxidation pathways and the associated vapor pressures affect biogenic new-particle formation at the molecular level. Our measurements therefore improve our understanding of pure biogenic new-particle formation for a wide range of tropospheric temperatures and precursor concentrations.

scholarly journals Hygroscopic properties and CCN activity of atmospheric aerosols under the influences of Asian continental outflow and new particle formation at a coastal site in East Asia

2019 ◽  
Author(s):  
Hing Cho Cheung ◽  
Charles C.-K. Chou ◽  
Celine S. L. Lee ◽  
Wei-Chen Kuo ◽  
Shuenn-Chin Chang
Keyword(s):  
Chemical Composition ◽  
Atmospheric Aerosols ◽  
Cloud Condensation Nuclei ◽  
Northern China ◽  
Particle Formation ◽  
Number Concentration ◽  
New Particle Formation ◽  
Air Masses ◽  
Hygroscopic Properties ◽  
Ccn Activity

Abstract. The chemical composition of fine particulate matters (PM2.5), the size distribution and number concentration of aerosol particles (NCN) and the number concentration of cloud condensation nuclei (NCCN) were measured at the northern tip of Taiwan Island during a campaign from April 2017 to March 2018. The parameters of aerosol hygroscopicity (i.e. activation ratio, activation diameter and kappa) were retrieved from the measurements. Significant variations were found in the hygroscopicity of aerosols, which were suggested be subject to various pollution sources, including aged air pollutants originating in the eastern/northern China and transported on the Asian continental outflows, fresh particles emitted from local sources and distributed by land-sea breeze circulations as well as produced by new particle formation (NPF) processes. Cluster analysis was applied to the backward trajectories of air masses to investigate their respective source regions. The results showed that the aerosols associated with Asian continental outflows were characterized with higher kappa values, whereas higher NCCN and NCN with lower kappa values were found for aerosols in local air masses. The distinct features in hygroscopicity were consistent with the characteristics in the chemical composition of PM2.5. Moreover, this study revealed that the nucleation mode particles from NPF could have participated in the enhancement of CCN activity, most likely by coagulating with sub-CCN particles, although the freshly produced particles were not favored for CCN activation due to their smaller sizes. Thus, the results of this study suggested that the NPF coupling with coagulation processes can significantly increase the NCCN in atmosphere.

scholarly journals New particle formation at urban and high-altitude remote sites in the south-eastern Iberian Peninsula

2020 ◽  
Author(s):  
Juan Andrés Casquero-Vera ◽  
Hassan Lyamani ◽  
Lubna Dada ◽  
Simo Hakala ◽  
Pauli Paasonen ◽  
...  
Keyword(s):  
High Altitude ◽  
Atmospheric Aerosols ◽  
Global Climate ◽  
Cloud Condensation Nuclei ◽  
Particle Formation ◽  
Aerosol Size Distribution ◽  
Urban Site ◽  
Special Importance ◽  
New Particle Formation ◽  
Remote Sites

Abstract. A substantial fraction of the atmospheric aerosols originates from secondary new particle formation (NPF), where atmospheric vapours are transformed into particles that subsequently grow to larger sizes, affecting human health and the climate. In this study, we investigate aerosol size distributions at two stations located close to each other (~ 20 km), but at different altitudes: urban (UGR; 680 m a.s.l.) and high-altitude remote (SNS; 2500 m a.s.l.) site, both in the area of Granada, Spain, and part of AGORA observatory (Andalusian Global ObseRvatory of the Atmosphere). The analysis shows a significant contribution of nucleation mode aerosol particles to the total aerosol number concentration at both sites, with a contribution of 47 % and 48 % at SNS and UGR, respectively. Due to the important contribution of NPF events to the total aerosol number concentrations and their high occurrence frequency (> 70 %) during the study period, a detailed analysis of NPF events is done in order to get insight into the possible mechanisms and processes involved in NPF events at these contrastive sites. At SNS, NPF is found to be associated with the transport of gaseous precursors from lower altitudes by orographic buoyant upward flows. However, NPF events at SNS site are always observed from the smallest measured sizes of the aerosol size distribution (4 nm), implying that NPF takes place in or in the vicinity of the high-altitude SNS station rather than transported from lower altitudes. Although NPF events at the mountain site seem to be connected with those occurring at the urban site, growth rates (GR) at SNS are higher than those at UGR site (GR7–25 of 6.9 and 4.5 nm h−1 and GR4–7 of 4.1 and 3.6 nm h−1 at SNS and UGR, respectively). This fact could have a special importance on the production of cloud condensation nuclei (CCN) and therefore on cloud formations which may affect regional/global climate, since larger GR at mountain sites could be translated to larger survival probability of NPF particles to reach CCN sizes, due to shorter time needed for the growth. The analysis of sulfuric acid (H2SO4) shows that the contribution of H2SO4 is able to explain a minimal fraction contribution to the observed GRs at both sites (

scholarly journals Molecular understanding of new-particle formation from <i>α</i>-pinene between −50 and +25 °C

2020 ◽  
Vol 20 (15) ◽  
pp. 9183-9207 ◽  
Author(s):  
Mario Simon ◽  
Lubna Dada ◽  
Martin Heinritzi ◽  
Wiebke Scholz ◽  
Dominik Stolzenburg ◽  
...  
Keyword(s):  
Oxidation State ◽  
Atmospheric Aerosols ◽  
Particle Formation ◽  
Oxidation Products ◽  
Basis Set ◽  
Ionization Mass ◽  
Vapor Pressures ◽  
New Particle Formation ◽  
Wide Range ◽  
Earth’S Climate

Abstract. Highly oxygenated organic molecules (HOMs) contribute substantially to the formation and growth of atmospheric aerosol particles, which affect air quality, human health and Earth's climate. HOMs are formed by rapid, gas-phase autoxidation of volatile organic compounds (VOCs) such as α-pinene, the most abundant monoterpene in the atmosphere. Due to their abundance and low volatility, HOMs can play an important role in new-particle formation (NPF) and the early growth of atmospheric aerosols, even without any further assistance of other low-volatility compounds such as sulfuric acid. Both the autoxidation reaction forming HOMs and their NPF rates are expected to be strongly dependent on temperature. However, experimental data on both effects are limited. Dedicated experiments were performed at the CLOUD (Cosmics Leaving OUtdoor Droplets) chamber at CERN to address this question. In this study, we show that a decrease in temperature (from +25 to −50 ∘C) results in a reduced HOM yield and reduced oxidation state of the products, whereas the NPF rates (J1.7 nm) increase substantially. Measurements with two different chemical ionization mass spectrometers (using nitrate and protonated water as reagent ion, respectively) provide the molecular composition of the gaseous oxidation products, and a two-dimensional volatility basis set (2D VBS) model provides their volatility distribution. The HOM yield decreases with temperature from 6.2 % at 25 ∘C to 0.7 % at −50 ∘C. However, there is a strong reduction of the saturation vapor pressure of each oxidation state as the temperature is reduced. Overall, the reduction in volatility with temperature leads to an increase in the nucleation rates by up to 3 orders of magnitude at −50 ∘C compared with 25 ∘C. In addition, the enhancement of the nucleation rates by ions decreases with decreasing temperature, since the neutral molecular clusters have increased stability against evaporation. The resulting data quantify how the interplay between the temperature-dependent oxidation pathways and the associated vapor pressures affect biogenic NPF at the molecular level. Our measurements, therefore, improve our understanding of pure biogenic NPF for a wide range of tropospheric temperatures and precursor concentrations.

scholarly journals Estimating neutral nanoparticle steady-state size distribution and growth according to measurements of intermediate air ions

2013 ◽  
Vol 13 (18) ◽  
pp. 9597-9603 ◽  
Author(s):  
H. Tammet ◽  
K. Komsaare ◽  
U. Hõrrak
Keyword(s):  
Growth Rate ◽  
Steady State ◽  
Size Distribution ◽  
Atmospheric Aerosols ◽  
Particle Formation ◽  
New Particle Formation ◽  
High Concentration ◽  
State Equations ◽  
Charged Aerosol ◽  
Ion Size

Abstract. Continuous measurements of intermediate air ion size distributions were carried out in the small town Tartu, Estonia, from 1 April 2010 through 7 November 2011. The intermediate ions are charged aerosol particles of diameter 1.5–7.5 nm. In this paper we study what information about neutral nanoparticles of atmospheric aerosols can be drawn from the air ion measurements. Rough estimates of the growth rate and the size distribution of neutral nanoparticles were derived for the subset of measurements while the concentration of the intermediate ions was close to the median and remains in the range of 21 ± 2 cm−3. This criterion excludes the specific new particle formation events characterized with high concentration of intermediate ions and includes only most typical quiet periods between the events when the simultaneous growth, depletion and recharging of particles are described with steady-state equations. We estimated the growth rate of nanoparticles to be about 2 nm h−1 while the growth flux or apparent nucleation rate proved to be about 0.5 cm−3 s−1 at 3 nm and about 0.08 cm−3 s−1 at 7 nm. The results suggest that the process of new particle formation is not interrupted during the quiet periods between events of intensive nucleation of atmospheric aerosols.

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