scholarly journals Aerosol formation and growth rates from chamber experiments using Kalman smoothing

2021 ◽  
Author(s):  
Matthew Ozon ◽  
Dominik Stolzenburg ◽  
Lubna Dada ◽  
Aku Seppänen ◽  
Kari E. J. Lehtinen
Keyword(s):  
Size Distribution ◽  
Growth Rates ◽  
Numerical Models ◽  
Formation Rate ◽  
Kernel Functions ◽  
The Other ◽  
Aerosol Size Distribution ◽  
Aerosol Formation ◽  
Distribution Dynamics ◽  
Kalman Smoothing

Abstract. Bayesian state estimation in the form of Kalman smoothing was applied to Differential Mobility Analyser Train (DMA-train) measurements of aerosol size distribution dynamics. Four experiments were analysed in order to estimate the aerosol size distribution, formation rate and size-dependent growth rate, as functions of time. The first analysed case was a synthetic one, generated by a detailed aerosol dynamics model, and the other three chamber experiments performed at the CERN CLOUD facility. The estimated formation and growth rates were compared with other methods used earlier for the CLOUD data and with the true values for the computer-generated synthetic experiment. The agreement in the growth rates was remarkably good for all studied cases. The formation rates matched also well, especially considering the fact that they were estimated from data given by two different instruments, the other being the Particle Size magnifier (PSM). The presented Fixed Interval Kalman Smoother (FIKS) method has clear advantages compared with earlier methods that have been applied to this kind of data. First, FIKS can reconstruct the size distribution between possible size gaps in the measurement in such a way that it is consistent with aerosol size distribution dynamics theory, and second, the method gives rise to direct and reliable estimation of size distribution and process rate uncertainties if the uncertainties in the kernel functions and numerical models are known.

scholarly journals Aerosol formation and growth rates from chamber experiments using Kalman smoothing

2021 ◽  
Vol 21 (16) ◽  
pp. 12595-12611 ◽  
Author(s):  
Matthew Ozon ◽  
Dominik Stolzenburg ◽  
Lubna Dada ◽  
Aku Seppänen ◽  
Kari E. J. Lehtinen
Keyword(s):  
Size Distribution ◽  
Growth Rates ◽  
Numerical Models ◽  
Kernel Functions ◽  
The Other ◽  
Aerosol Size Distribution ◽  
Aerosol Formation ◽  
Distribution Dynamics ◽  
Kalman Smoother ◽  
Kalman Smoothing

Abstract. Bayesian state estimation in the form of Kalman smoothing was applied to differential mobility analyser train (DMA-train) measurements of aerosol size distribution dynamics. Four experiments were analysed in order to estimate the aerosol size distribution, formation rate, and size-dependent growth rate, as functions of time. The first analysed case was a synthetic one, generated by a detailed aerosol dynamics model and the other three chamber experiments performed at the CERN CLOUD facility. The estimated formation and growth rates were compared with other methods used earlier for the CLOUD data and with the true values for the computer-generated synthetic experiment. The agreement in the growth rates was very good for all studied cases: estimations with an earlier method fell within the uncertainty limits of the Kalman smoother results. The formation rates also matched well, within roughly a factor of 2.5 in all cases, which can be considered very good considering the fact that they were estimated from data given by two different instruments, the other being the particle size magnifier (PSM), which is known to have large uncertainties close to its detection limit. The presented fixed interval Kalman smoother (FIKS) method has clear advantages compared with earlier methods that have been applied to this kind of data. First, FIKS can reconstruct the size distribution between possible size gaps in the measurement in such a way that it is consistent with aerosol size distribution dynamics theory, and second, the method gives rise to direct and reliable estimation of size distribution and process rate uncertainties if the uncertainties in the kernel functions and numerical models are known.

scholarly journals Results from the CERN pilot CLOUD experiment

2010 ◽  
Vol 10 (4) ◽  
pp. 1635-1647 ◽  
Author(s):  
J. Duplissy ◽  
M. B. Enghoff ◽  
K. L. Aplin ◽  
F. Arnold ◽  
H. Aufmhoff ◽  
...  
Keyword(s):  
Sulphuric Acid ◽  
Growth Rates ◽  
Formation Rate ◽  
Detection Threshold ◽  
Proton Synchrotron ◽  
Aerosol Formation ◽  
Stringent Requirement ◽  
Pilot Experiment ◽  
Aerosol Chamber ◽  
Ion Recombination

Abstract. During a 4-week run in October–November 2006, a pilot experiment was performed at the CERN Proton Synchrotron in preparation for the Cosmics Leaving OUtdoor Droplets (CLOUD) experiment, whose aim is to study the possible influence of cosmic rays on clouds. The purpose of the pilot experiment was firstly to carry out exploratory measurements of the effect of ionising particle radiation on aerosol formation from trace H2SO4 vapour and secondly to provide technical input for the CLOUD design. A total of 44 nucleation bursts were produced and recorded, with formation rates of particles above the 3 nm detection threshold of between 0.1 and 100 cm−3s−1, and growth rates between 2 and 37 nm h−1. The corresponding H2O concentrations were typically around 106 cm−3 or less. The experimentally-measured formation rates and H2SO4 concentrations are comparable to those found in the atmosphere, supporting the idea that sulphuric acid is involved in the nucleation of atmospheric aerosols. However, sulphuric acid alone is not able to explain the observed rapid growth rates, which suggests the presence of additional trace vapours in the aerosol chamber, whose identity is unknown. By analysing the charged fraction, a few of the aerosol bursts appear to have a contribution from ion-induced nucleation and ion-ion recombination to form neutral clusters. Some indications were also found for the accelerator beam timing and intensity to influence the aerosol particle formation rate at the highest experimental SO2 concentrations of 6 ppb, although none was found at lower concentrations. Overall, the exploratory measurements provide suggestive evidence for ion-induced nucleation or ion-ion recombination as sources of aerosol particles. However in order to quantify the conditions under which ion processes become significant, improvements are needed in controlling the experimental variables and in the reproducibility of the experiments. Finally, concerning technical aspects, the most important lessons for the CLOUD design include the stringent requirement of internal cleanliness of the aerosol chamber, as well as maintenance of extremely stable temperatures (variations below 0.1 °C

scholarly journals Modeling kinetic partitioning of secondary organic aerosol and size distribution dynamics: representing effects of volatility, phase state, and particle-phase reaction

2014 ◽  
Vol 14 (10) ◽  
pp. 5153-5181 ◽  
Author(s):  
R. A. Zaveri ◽  
R. C. Easter ◽  
J. E. Shilling ◽  
J. H. Seinfeld
Keyword(s):  
Size Distribution ◽  
Rate Constant ◽  
Secondary Organic Aerosol ◽  
Organic Aerosol ◽  
Diffusion Reaction ◽  
Aerosol Size Distribution ◽  
Particle Phase ◽  
Distribution Dynamics ◽  
Bulk Diffusivity ◽  
New Framework

Abstract. This paper describes and evaluates a new framework for modeling kinetic gas-particle partitioning of secondary organic aerosol (SOA) that takes into account diffusion and chemical reaction within the particle phase. The framework uses a combination of (a) an analytical quasi-steady-state treatment for the diffusion–reaction process within the particle phase for fast-reacting organic solutes, and (b) a two-film theory approach for slow- and nonreacting solutes. The framework is amenable for use in regional and global atmospheric models, although it currently awaits specification of the various gas- and particle-phase chemistries and the related physicochemical properties that are important for SOA formation. Here, the new framework is implemented in the computationally efficient Model for Simulating Aerosol Interactions and Chemistry (MOSAIC) to investigate the competitive growth dynamics of the Aitken and accumulation mode particles. Results show that the timescale of SOA partitioning and the associated size distribution dynamics depend on the complex interplay between organic solute volatility, particle-phase bulk diffusivity, and particle-phase reactivity (as exemplified by a pseudo-first-order reaction rate constant), each of which can vary over several orders of magnitude. In general, the timescale of SOA partitioning increases with increase in volatility and decrease in bulk diffusivity and rate constant. At the same time, the shape of the aerosol size distribution displays appreciable narrowing with decrease in volatility and bulk diffusivity and increase in rate constant. A proper representation of these physicochemical processes and parameters is needed in the next generation models to reliably predict not only the total SOA mass, but also its composition- and number-diameter distributions, all of which together determine the overall optical and cloud-nucleating properties.

scholarly journals Observation of aerosol size distribution and new particle formation at a mountain site in subtropical Hong Kong

2012 ◽  
Vol 12 (20) ◽  
pp. 9923-9939 ◽  
Author(s):  
H. Guo ◽  
D. W. Wang ◽  
K. Cheung ◽  
Z. H. Ling ◽  
C. K. Chan ◽  
...  
Keyword(s):  
Growth Rate ◽  
Hong Kong ◽  
Sulfuric Acid ◽  
Size Distribution ◽  
Formation Rate ◽  
Particle Formation ◽  
Aerosol Size Distribution ◽  
New Particle Formation ◽  
Average Growth ◽  
Nucleation Mode

Abstract. In order to investigate the formation and growth processes of nucleation mode particles, and to quantify the particle number (PN) concentration and size distributions in Hong Kong, an intensive field measurement was conducted from 25 October to 29 November in 2010 near the mountain summit of Tai Mo Shan, a suburban site approximately the geographical centre of the New Territories in Hong Kong. Based on observations of the particle size distribution, new particle formation (NPF) events were found on 12 out of 35 days with the estimated formation rate J5.5 from 0.97 to 10.2 cm−3 s−1, and the average growth rates from 1.5 to 8.4 nm h−1. The events usually began at 10:00–11:00 LT characterized by the occurrence of a nucleation mode with a peak diameter of 6–10 nm. Solar radiation, wind speed, sulfur dioxide (SO2) and ozone (O3) concentrations were on average higher, whereas temperature, relative humidity and daytime nitrogen dioxide (NO2) concentration were lower on NPF days than on non-NPF days. Back trajectory analysis suggested that in majority of the NPF event days, the air masses originated from the northwest to northeast directions. The concentrations of gaseous sulfuric acid (SA) showed good power-law relationship with formation rates, with exponents ranging from 1 to 2. The result suggests that the cluster activation theory and kinetic nucleation could potentially explain the observed NPF events in this mountainous atmosphere of Hong Kong. Meanwhile, in these NPF events, the contribution of sulfuric acid vapor to particle growth rate (GR5.5–25) ranged from 9.2 to 52.5% with an average of 26%. Measurement-based calculated oxidation rates of monoterpenes (i.e. α-pinene, β-pinene, myrcene and limonene) by O3 positively correlated with the GR5.5–25 (R = 0.80, p < 0.05). The observed associations of the estimated formation rate J5.5 and the growth rate GR5.5–25 with gaseous sulfuric acid and volatile organic compounds (VOCs) suggested the critical roles of sulfuric acid and biogenic VOCs (e.g. α-pinene and β-pinene) in these NPF events.

Aerosol formation from heat and mass transfer in vapour–gas mixtures

1985 ◽  
Vol 398 (1815) ◽  
pp. 307-339 ◽  
Keyword(s):  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Heat Transport ◽  
Water Vapour ◽  
Formation Rate ◽  
Aerosol Size Distribution ◽  
Atmospheric Effects ◽  
Aerosol Formation ◽  
Pressurized Water ◽  
Small Diffusion

Heat and mass transfer equations and their coupling to the equation for the aerosol size distribution are examined for mixtures in which pressure changes are slow. Equilibrium between an aerosol and its surrounding vapour is shown to be generally fast so that vapour supersaturations are small. Diffusion and conduction control evaporation and condensation on aerosols so that the sign of the aerosol growth term can be determined by the ratio of their relative rates, given by the Lewis number, Le ; for example where Le < 1, as for water vapour–air mixtures, aerosols may evaporate as the mixture is cooled. A ‘condensation number’, Cn ( T ), representing the ratio of the rate of heat transport to that of latent heat by vapour diffusion, and which is a strong function of temperature, is introduced to describe the other main controlling physical effect in aerosol formation. Where Cn ≪ 1, as for high-temperature water vapour–air mixtures, the proportion of vapour that can condense as an aerosol is very small. For a fixed total heat transport rate, the maximum aerosol formation rate occurs near Cn ( T ) = 1, which is at T ≈ 4°C for water vapour–air mixtures at 1 atm pressure (101 325 Pa). Specific results in terms of Cn and Le are obtained for the proportion of vapour condensing as an aerosol during the cooling and heating of a mixture in a well-mixed cavity. The assumption of allowing no supersaturations, the validity of which is examined, is shown to lead to maximum aerosol formation. For water vapour–air mixtures predictions are made as to temperature regions in which aerosols will evaporate or not form in cooling processes. The results are also qualitatively applied to some atmospheric effects as well as to water aerosols formed in the containment of a pressurized water reactor following a possible accident. In this context the present conclusion that the whereabouts of vapour condensation is controlled by heat and mass transfer contrasts with previous assumptions that the controlling factor is relative surface areas.

scholarly journals Size distribution dynamics reveal particle-phase chemistry in organic aerosol formation

2013 ◽  
Vol 110 (29) ◽  
pp. 11746-11750 ◽  
Author(s):  
M. Shiraiwa ◽  
L. D. Yee ◽  
K. A. Schilling ◽  
C. L. Loza ◽  
J. S. Craven ◽  
...  
Keyword(s):  
Size Distribution ◽  
Organic Aerosol ◽  
Particle Phase ◽  
Aerosol Formation ◽  
Distribution Dynamics ◽  
Phase Chemistry

scholarly journals Results from the CERN pilot CLOUD experiment

2009 ◽  
Vol 9 (5) ◽  
pp. 18235-18270 ◽  
Author(s):  
J. Duplissy ◽  
M. B. Enghoff ◽  
K. L. Aplin ◽  
F. Arnold ◽  
H. Aufmhoff ◽  
...  
Keyword(s):  
Sulphuric Acid ◽  
Growth Rates ◽  
Formation Rate ◽  
Detection Threshold ◽  
Proton Synchrotron ◽  
Aerosol Formation ◽  
Stringent Requirement ◽  
Pilot Experiment ◽  
Aerosol Chamber ◽  
Ion Recombination

Abstract. During a 4-week run in October–November 2006, a pilot experiment was performed at the CERN Proton Synchrotron in preparation for the CLOUD1 experiment, whose aim is to study the possible influence of cosmic rays on clouds. The purpose of the pilot experiment was firstly to carry out exploratory measurements of the effect of ionising particle radiation on aerosol formation from trace H2SO4 vapour and secondly to provide technical input for the CLOUD design. A total of 44 nucleation bursts were produced and recorded, with formation rates of particles above the 3 nm detection threshold of between 0.1 and 100 cm−3s−1, and growth rates between 2 and 37 nm h−1. The corresponding H2SO4 concentrations were typically around 106 cm−3 or less. The experimentally-measured formation rates and H2SO4 concentrations are comparable to those found in the atmosphere, supporting the idea that sulphuric acid is involved in the nucleation of atmospheric aerosols. However, sulphuric acid alone is not able to explain the observed rapid growth rates, which suggests the presence of additional trace vapours in the aerosol chamber, whose identity is unknown. By analysing the charged fraction, a few of the aerosol bursts appear to have a contribution from ion-induced nucleation and ion-ion recombination to form neutral clusters. Some indications were also found for the accelerator beam timing and intensity to influence the aerosol particle formation rate at the highest experimental SO2 concentrations of 6 ppb, although none was found at lower concentrations. Overall, the exploratory measurements provide suggestive evidence for ion-induced nucleation or ion-ion recombination as sources of aerosol particles. However in order to quantify the conditions under which ion processes become significant, improvements are needed in controlling the experimental variables and in the reproducibility of the experiments. Finally, concerning technical aspects, the most important lessons for the CLOUD design include the stringent requirement of internal cleanliness of the aerosol chamber, as well as maintenance of extremely stable temperatures (variations below 0.1°C). 1CLOUD is an acronym of Cosmics Leaving OUtdoor Droplets.

scholarly journals Modeling kinetic partitioning of secondary organic aerosol and size distribution dynamics: representing effects of volatility, phase state, and particle-phase reaction

2013 ◽  
Vol 13 (11) ◽  
pp. 28631-28694 ◽  
Author(s):  
R. A. Zaveri ◽  
R. C. Easter ◽  
J. E. Shilling ◽  
J. H. Seinfeld
Keyword(s):  
Size Distribution ◽  
Rate Constant ◽  
Secondary Organic Aerosol ◽  
Organic Aerosol ◽  
Diffusion Reaction ◽  
Aerosol Size Distribution ◽  
Particle Phase ◽  
Distribution Dynamics ◽  
Bulk Diffusivity ◽  
New Formulation

Abstract. This paper describes and evaluates a new formulation for modeling kinetic gas-particle partitioning of secondary organic aerosol (SOA) that takes into account diffusion and chemical reaction within the particle phase. The new formulation uses a combination of: (a) an analytical quasi-steady-state treatment for the diffusion-reaction process within the particle phase for fast-reacting organic solutes, and (b) a two-film theory approach for slow- and non-reacting solutes. The formulation is amenable for use in regional and global atmospheric models, although it currently awaits specification of the actual species and particle-phase reactions that are important for SOA formation. Here, the formulation is applied within the framework of the computationally efficient Model for Simulating Aerosol Interactions and Chemistry (MOSAIC) to investigate the competitive growth dynamics of the Aitken and accumulation mode particles. Results show that the timescale of SOA partitioning and the associated size distribution dynamics depend on the complex interplay between organic solute volatility, particle-phase bulk diffusivity, and particle-phase reactivity (as exemplified by a pseudo-first-order reaction rate constant), each of which can vary over several orders of magnitude. In general, the timescale of SOA partitioning increases with increase in volatility and decrease in bulk diffusivity and rate constant. At the same time, the shape of the aerosol size distribution displays appreciable narrowing with decrease in volatility and bulk diffusivity and increase in rate constant. A proper representation of these physicochemical processes and parameters are needed in the next generation models to reliably predict not only the total SOA mass, but also its composition and number size distribution, all of which together determine its overall optical and cloud-nucleating properties.

scholarly journals Secondary organic aerosol formation during June 2010 in Central Europe: measurements and modelling studies with a mixed thermodynamic-kinetic approach

2014 ◽  
Vol 14 (8) ◽  
pp. 3831-3842 ◽  
Author(s):  
B. Langmann ◽  
K. Sellegri ◽  
E. Freney
Keyword(s):  
Organic Carbon ◽  
Size Distribution ◽  
Atmospheric Chemistry ◽  
Mass Concentration ◽  
Three Dimensional ◽  
Kinetic Approach ◽  
Aerosol Size Distribution ◽  
Aerosol Formation ◽  
Organic Vapour ◽  
Mass Concentrations

Abstract. Until recently secondary organic carbon aerosol (SOA) mass concentrations have been systematically underestimated by three-dimensional atmospheric-chemistry-aerosol models. With a newly proposed concept of aging of organic vapours, more realistic model results for organic carbon aerosol mass concentrations can be achieved. Applying a mixed thermodynamic-kinetic approach for SOA formation shifted the aerosol size distribution towards particles in the cloud condensation nuclei size range, thereby emphasising the importance of SOA formation schemes for modelling realistic cloud and precipitation formation. The additional importance of hetero-molecular nucleation between H2SO4 and organic vapours remains to be evaluated in three-dimensional atmospheric-chemistry-aerosol models. Here a case study is presented focusing on Puy-de-Dôme, France in June 2010. The measurements indicate a considerable increase in SOA mass concentration during the measurement campaign, which could be reproduced by modelling using a simplified thermodynamic-kinetic approach for SOA formation and increased biogenic volatile organic compound (VOC) precursor emissions. Comparison with a thermodynamic SOA formation approach shows a huge improvement in modelled SOA mass concentration with the thermodynamic-kinetic approach for SOA formation. SOA mass concentration increases by a factor of up to 6 accompanied by a slight improvement of modelled particle size distribution. Even though nucleation events at Puy-de-Dôme were rare during the chosen period of investigation, a weak event in the boundary layer could be reproduced by the model in a sensitivity study when nucleation of low-volatile secondary organic vapour is included. Differences in the model results with and without nucleation of organic vapour are visible in the lower free troposphere over several days. Taking into account the nucleation of organic vapour leads to an increase in accumulation mode particles due to coagulation and condensational growth of nucleation and Aitken mode particles.

Sign in / Sign up

Export Citation Format

Share Document