Particle Mass Distribution Research Articles

Multimass Analysis of Adeno-Associated Virus Vectors by Orbitrap-Based Charge Detection Mass Spectrometry.

Adeno-associated virus (AAV) vectors have attracted significant attention as the main platform for gene therapy. To ensure the safety and efficacy of AAV vectors when used as gene therapy drugs, it is essential to assess their critical quality attributes (CQAs). These CQAs include the genome packaging status, the size of the genome encapsidated within the AAV capsid, and the stoichiometry of viral proteins (VPs) that constitute the AAV capsids. Analytical methods have been established for evaluating CQAs, such as analytical ultracentrifugation, capillary gel electrophoresis with laser-induced fluorescence detection, and capillary gel electrophoresis using sodium dodecyl sulfate with UV detection. Here, we present a multimass analysis of AAV vectors using orbitrap-based charge detection mass spectrometry (CDMS), a single-ion mass spectrometry. Orbitrap-based CDMS facilitates the quantitative evaluation of the genome packaging status based on the mass distribution of empty and full particles. Additionally, we established a novel method to analyze the encapsidated genome directly without pretreatment, such as protein digestion or heat treatment, and to estimate the stoichiometric variation of VP for the capsid based on the mass distribution constituted by the single peak corresponding to AAV particles. Orbitrap-based CDMS is a distinctive method that allows multiple mass characterizations of AAV vectors with a small sample volume of 20 μL for 1013 cp/mL in a short time (30 min), and it holds the potential to become a new standard method in the assessment of CQAs for AAV vectors.

Numerical investigation of the physical-thermal-chemical behaviours of particles during coal combustion and desulfurization processes in a CFB combustor

The desulfurization process has been practised for the clean utilization of coal in chemical engineering fields, yet the physical, thermal, and chemical characteristics of particles are still lacking understanding. In this work, a comprehensive numerical model based on the Eulerian-Lagrangian framework was established to study the particle behaviours during coal combustion and desulfurization processes in a pilot-scale circulating fluidized bed (CFB) combustor. After model validation, the effects of several crucial operation parameters (e.g., excess air ratio, calcium to sulphur ratio, and calcium oxide size) on particle behaviours are illuminated. The results show that density-induced segregation causes coal particles to accumulate in the upper part of the riser. The sand, coal, and CaO particles have time-averaged Reynolds numbers of 15, 6.5, and 0.5, respectively. The particle temperature is higher in areas with lower solid concentrations. Increasing excess air ratio (ϕg) decreases the temperature of sand particles but elevates that of coal and CaO particles. The average particle heat transfer coefficients (HTCs) for sand, coal, and CaO particles are 205 W/m2·K, 172 W/m2·K, and 275 W/m2·K, respectively. With the increase in ϕg, the HTC of sand particles increases but that of CaO particles remains unchanged, additionally, the mass of coal particles decreases and the mass of carbon in coal particles decreases along with the riser. The influence of the Ca/S ratio and CaO size on the axial distribution of coal particle mass and carbon mass fraction is negligible. For each particle species, the axial dispersion coefficient (Dz) is two orders of magnitude greater than the radial ones (Dx, Dy), indicating that the vertical introduction of the fluidizing gas dominates the dense gas-solid flow in the riser.

Design and optimization of gradient fibrous media using the method of moments

The goal of this work is to optimize the deposition mass distribution of polydisperse particles inside the fibrous media by modifying the distribution of the fiber packing density across filter depth. Two types of gradient fibrous media with linear and exponential fiber packing density distribution along the flow direction were derived. The method of moments was employed to study the transport and deposition characteristics of polydisperse aerosol particles inside the fibrous media. The reliability of the calculated results by the method of moments was confirmed by the numerical simulations based on the discrete phase model (DPM). Results indicate that the gradient fibrous media allows more particles to transport and deposit into the interior of the fibrous media, which improves the uniformity of particle deposition distribution across filter depth. There exists an optimal fiber packing density distribution ratio for the gradient fibrous media where the non-uniformity of deposition mass distribution of polydisperse particles across filter depth is minimized. In this way, uniform deposition distribution along the flow direction can be generally achieved by optimizing the fiber packing density distribution, which will contribute to the optimal design of microstructures for the fibrous filter.

Optofluidic Force Induction Meets Raman Spectroscopy and Inductively Coupled Plasma-Mass Spectrometry: A New Hyphenated Technique for Comprehensive and Complementary Characterizations of Single Particles.

Nanoparticles are produced at accelerating rates, are increasingly integrated into scientific and industrial applications, and are widely discharged into the environment. Analytical techniques are required to characterize parameters such as particle number concentrations, mass and size distributions, molecular and elemental compositions, and particle stability. This is not only relevant to investigate their utility for various industrial or medical applications and for controlling the manufacturing processes but also to assess toxicity and environmental fate. Different analytical strategies aim to characterize certain facets of particles but are difficult to combine to retrieve relevant parameters coherently and to provide a more comprehensive picture. In this work, we demonstrate the first online hyphenation of optofluidic force induction (OF2i) with Raman spectroscopy and inductively coupled plasma-time-of-flight-mass spectrometry (ICP-TOFMS) to harness their complementary technology-specific advantages and to promote comprehensive particle characterizations. We optically trapped individual particles on a weakly focused vortex laser beam by aligning a microfluidic flow antiparallelly to the laser propagation direction. The position of particles in this optical trap depended on the hydrodynamic diameter and therefore enabled size calibration as well as matrix elimination. Additionally, laser light scattered on particles was analyzed in a single particle (SP) Raman spectroscopy setup for the identification of particulate species and phases. Finally, particles were characterized regarding elemental composition and their distributions in mass and size using SP ICP-TOFMS. In a proof of concept, we analyzed polystyrene-based microplastic and TiO2 nanoparticles and demonstrated the opportunities provided through the coupling of OF2i with SP Raman and SP ICP-TOFMS.

Influence of Lowering Soot‐Water Contact Angle on Ice Nucleation of Ozone‐Aged Soot

AbstractOrganic‐lean and organic‐rich size‐selected soot particles were exposed to a varying O3 concentration, progressively decreasing the soot‐water contact angle (θ) to study its impact on ice nucleation (IN). The IN ability of fresh and O3‐aged soot between 218 and 233 K was observed while monitoring the particle mass and size distributions. The properties of fresh and O3‐aged bulk organic‐lean soot samples with a low and high O3‐adsorption were characterized for soot‐water θ, chemical composition, functional groups, soot‐water interaction ability and porosity. By retaining the soot porosity between aged and unaged samples, we demonstrate that a decrease in θ after O3‐aging enhances organic‐lean soot IN via pore condensation and freezing. Fresh organic‐rich soot exhibits suppressed homogeneous freezing, but after O3‐aging it freezes within uncertainty of the homogeneous freezing threshold of solution drops, because of increased hydrophilicity.

Influence of ozone pollution on the mixing state and formation of oxygenated organics containing single particles

The formation and aging processes of oxygenated organic molecules (OOMs) are important for understanding the formation mechanisms of secondary organic aerosols (SOAs) in the field. In this study, we investigated the mixing states of OOM particles by identifying several oxygenated species along with the distributions of secondary organic carbon (SOC) during both clean and ozone (O3)-polluted periods in July and September of 2022 in Guangzhou, China. OOM-containing particles accounted for 57 % and 49 % of the total detected single particles in July and September, respectively. Most of the OOM particles were internally mixed with sulfate and nitrate, while elemental carbon and hydrocarbon species were absent. Despite the higher SOC/OC ratio in September (81 %) than it in July (72 %), comparative investigations of the mass spectra, diurnal patterns, and distributions of OOM particles revealed the same composition and aging states of OOMs in two O3 pollution periods. As the O3 concentration increased from the clean to the polluted periods, the ratio of SOC to OC increased along with the relative abundance of secondary OOM particles among total OOM particles. In contrast, the relative abundance of OC-type OOM particles gradually decreased, indicating the conversion of hydrocarbon species into OOMs as the SOC/OC ratio increased. Both the bulk analysis of SOC from filter measurement and the mixing states of OOM particles suggested that OOM production and degree of oxidation were higher in the O3-polluted periods than in the clean periods. These results elucidate the effects of O3 pollution on the OOM formation process and offer new perspectives for the joint investigation of SOA production based on filter sampling and single-particle measurements.

An Experimental Study on the Fine Particle Emissions of Brake Pads According to Different Conditions Assuming Vehicle Deceleration with Pin-on-Disc Friction Test

Fine particles from vehicles occur in a range of particulate matter (PM) sizes and influence the roadside atmosphere. The contribution of fine dust from automobiles to road pollution has reportedly been extremely high. Researchers have estimated that non-exhaust fine dust originating from brakes, tires, clutches, and road surface wear rate is increasing. Several studies have shown that brake pads account for a significant proportion of non-exhaust emissions. In this study, a friction test using vehicle brake pads was carried out with a friction tester to reveal the harmfulness of brake pad particles by the driver’s driving habits. Conditions were made considering the pressure, vehicle speed, and temperature and assuming the amount of deceleration of the vehicle. Particle collection devices were used to analyze the concentration of number and the mass distribution of particles produced in the experiment, with a range from 6 nm to 7.3 μm to gauge the toxicity of particles. The results showed that the number concentration of fine particles tended to increase linearly with changes in vehicle deceleration (braking energy) in the particle diameter region around 0.75–7.3 μm. The number concentration of fine particles tended to increase exponentially in the particle diameter region around 71–120 nm. The rapid occurrence of ultrafine particles in nanometers varied depending on the test conditions.

A kinetic-based model for polydisperse, high-speed, fluid–particle flows

Hyperbolic conservation equations for polydisperse, high-speed, compressible, fluid–particle flows with added mass and fluid-phase pseudoturbulence are derived. First, the kinetic-based model for monodisperse particles that accounts for collisional and frictional pressure, as well as added mass and internal energy, is reviewed. Then, a kinetic-based model for polydisperse particles is formulated in terms of the moments of the particle size distribution, and velocity moments conditioned on the particle mass or size. Transport equations for velocity moments up to second order (or total kinetic energy) are closed using the hyperbolic quadrature method of moments. In the numerical implementation for the spatial fluxes and source terms, the particle mass distribution is treated using the generalized quadrature method of moments and the size-conditioned moments are found with the conditional quadrature method of moments. Example results for spatially 1-D test cases demonstrate the ability of the polydisperse model to capture a wide range of particle-size-dependent multiphase flow physics.

Pollution status, particle-size distribution and health impacts (people at different ages) of polybrominated diphenyl ethers in bedrooms

Polybrominated diphenyl ethers (PBDEs) are widely found in the environment owing to the widespread use of brominated flame retardants. In recent years, polybrominated diphenyl ethers have attracted increasing attention because of their harmful effects on human health, especially in children, and have been recognized as significant indoor environmental pollutants. In this study, PBDEs were detected in 80 samples of air, dust, and particulate matter from bedrooms in Hangzhou, indicating that PBDE pollutions in bedrooms occur widely. The median concentration of ∑8PBDEs in dust was 8.54 ng/g, whereas in air and particulate matter was 13.60 pg/m3 and 23.94 pg/m3, respectively. BDE-209 was the main congeners in particles and dust. The mass distribution of atmospheric particles in bedrooms showed a bimodal distribution, mainly in the segments of < 1.1 and 3.3 − 4.7 µm. Through the analysis of typical bedroom materials, the specific PBDEs concentration order was as follows: curtain < wallpaper < mattress < socket panel, with median concentrations of 21.90 µg/g, 45.74 µg/g, 46.31 µg/g and 74.85 µg/g, respectively. The possible sources of PBDEs in residential air, dust, particulate matter was mattress, curtains and mattresses, and mattress and curtains, respectively. Infants have the highest daily exposure dose (DED) for ∑5PBDEs in the air and particulate matter phases, while toddles have the highest DED in dust. The HQ（Hazard Quotient）of infants, toddlers, children, teenagers, and adults were 8.58E-05, 1.06E-04, 4.17E-05, 2.53E-05 and 1.09E-05, respectively, indicating that pollution in bedrooms will not negatively impact human health. However, related studies have shown that children are more likely to be exposed to PBDEs than adults. Therefore, for infants and young children with weaker resistance and long-term family environments, PBDEs pollution may harm their health and growth.

Distribution and evolution of particles in flash converting furnace under different operational conditions

A series of industrial experiments were conducted, not only to reveal the distribution and evolution of particle mass and size inside the flash converting furnace, but also to investigate the influence of airflows on the particle distribution. The results showed that the average size of particles grows 2–3 times when falling through the reaction shaft, and large aggregated particles were mainly distributed in the center and outer part of the material cone. This phenomenon was attributed to the collision and aggregation of molten particles caused by the high turbulent intensity of airflow, high particle mass concentration, and positions of natural gas combusting. Moreover, increasing the momentum ratio of the distribution air to the process air helped the particles to be distributed more uniformly, which could be beneficial to matte oxidation. Compared with changing process air, adjusting the distribution air could improve the particle spatial distribution more efficiently.

Particle Behavior and Aperture Optimization of Variable Vibration-Amplitude Screening Based on Discrete Element Method Simulation.

Recently, some novel screens were proposed based on the improved understanding of screening processes from particle-scale studies, one of which is the novel variable amplitude equal thickness vibration screen (VAETVS). This paper presents an investigation of using different aperture sizes to further optimize the VAETVS by the discrete element method (DEM). The screen was divided into three panels, and the aperture size of each panel was varied in the simulation. The particles' dynamics and spatial distribution were investigated to better understand the effects of varied amplitudes and aperture sizes on the screening efficiency. The results showed that the VAETVS can be effectively optimized by varied amplitude as well as varied aperture size for different screen panels. The amplitude variance is more effective for hard sieve particles and hindrance particles. It is also found that from the feed end to the discharge end, the difference in the distribution of particle mass between the coarse particles and the fine particles increases. Generally, such a difference can be increased with increasing aperture sizes. However, the effects of the apertures of the different panels were not the same. The simulated data were further analyzed by the Box-Behnken response surface method, which gave a mathematical model to predict the screening efficiency η with the varied apertures. From the model, the optimal aperture sizes are 7.5, 7.58, and 6.81 mm, yielding the maximum screening efficiency of 86.35%, and the optimal opening areas for the three panels are 35, 40, and 40%, respectively, yielding the maximum screening efficiency of 87.82%.

A stochastic model leading to various particle mass distributions including the RRSB distribution

Modern particle size statistics uses many different statistical distributions, but these distributions are empirical approximations for theoretically unknown relationships. This also holds true for the famous RRSB (Rosin-Rammler-Sperling-Bennett) distribution. Based on the compound Poisson process, this paper introduces a simple stochastic model that leads to a general product form of particle mass distributions. The beauty of this product form is that its two factors characterize separately the two main components of samples of particles, namely, individual particle masses and total particle number. The RRSB distribution belongs to the class of distributions following the new model. Its simple product form can be a starting point for developing new particle mass distributions. The model is applied to the statistical analysis of samples of blast-produced fragments measured by hand, which enables a precise investigation of the mass-size relationship. This model-based analysis leads to plausible estimates of the mass and size factors and helps to understand the influence of blasting conditions on fragment-mass distributions.

Methodological advances to improve repeatability of SOA generation in environmental chambers

Most laboratory atmospheric chamber studies probing the chemical and physical properties of secondary organic aerosol (SOA) perform such experiments with mixing ratios of volatile organic compounds (VOCs) above atmospheric relevance (≳50 ppbv). When performing ozonolysis of biogenic VOCs at mixing ratios of atmospheric relevance (≲10 ppbv), a major hinderance on the repeatability of replicate experiments is due to the limitations of conventional VOC injection techniques. To overcome these limitations, two novel components (stop/flow and split valves) were embedded in a conventional VOC injection setup, thereby permitting the use of higher VOC volumes of injection to attain low VOC mixing ratios, and the delivery of the VOC to the environmental chamber as a short, discrete pulse for subsequent reaction. Implementation of these novel VOC injection components has resulted in improvements in variability between replicate chamber experiments of up to a factor of 7 with respect to particle number, mass, and size distributions at both high and low VOC mixing ratios (50 and 10 ppbv, respectively). These improvements permit extension of quantitative measurements of SOA formation to VOC mixing ratios at or near atmospheric levels, where new particle formation (NPF) and SOA mass loading are typically within experimental variability.

Comprehensive study on particle size distribution, MAH and PAH profiles during alkylbenzene pyrolysis

The 5 linear alkylbenzenes, i.e., toluene, ethylbenzene, n-propylbenzene, n-butylbenzene, and n-pentylbenzene as fuels underwent pyrolysis at temperatures from 950 to 1450 °C in a flow reactor. Measurements of particle number size distribution, 11 monocyclic aromatic hydrocarbons, and 3 groups of polycyclic aromatic hydrocarbons (20 unsubstituted PAHs, 5 aliphatic-bridged PAHs, and 10 methyl PAHs) during the pyrolysis of linear alkylbenzenes were conducted. Results showed that the increase in side chain length suppressed the formation of particles, but ethylbenzene produced the highest particle mass and most extensive particle number size distribution. Total particle peak number concentrations exhibited a rise-then-fall trend (peaking at a critical temperature of 1050 °C) with increasing temperature regardless of the side chain length, indicating that high temperature promoted a transition from nucleation to agglomeration and coagulation. Total PAH mass concentrations were ranked in the same order with the variation of side-chain length as particle mass and peak number concentrations, indicating that soot nucleation was highly related to total PAH mass concentrations. Unsubstituted PAHs accounted for most PAHs while substituted·PAHs, including aliphatic-bridged PAHs and methyl PAHs presented 1–2 orders of magnitude less than the corresponding unsubstituted PAHs, probably distinct thermal stability and reactivity led to different growth routes between unsubstituted and substituted PAHs. Increasing the temperature from 950 to 1250 °C, the formation of high molecular weight PAHs was promoted. while a drop of high molecular weight fractions was observed above 1350 °C, which is attributed to the suppression of the formation, as well as their conversions of high molecular weight PAHs to heavier unidentified PAHs or soot. Among the test alkylbenzene fuels, the fuels with a long side chain benefit from the reduction of particles and PAHs. Furthermore, carbon atoms in aromatic rings are dominant sources of large PAHs and particles, while the carbon atoms in aliphatic side chains mainly form gas species.

Occurrence and size distribution study of microplastics in household water from different cities in continental Spain and the Canary Islands

The purpose of this study was to investigate the occurrence of microplastics (MPs) in drinking water in Spain by comparing tap water from different locations using common sampling and identification procedures. We sampled tap water from 24 points in 8 different locations from continental Spain and the Canary Islands by means of 25 μm opening size steel filters coupled to household connections. All particles were measured and spectroscopically characterized including not only MPs but also particles consisting of natural materials with evidence of industrial processing, such as dyed natural fibres, referred insofar as artificial particles (APs). The average concentration of MPs was 12.5 ± 4.9 MPs/m3 and that of anthropogenic particles 32.2 ± 12.5 APs/m3. The main synthetic polymers detected were polyamide, polyester, and polypropylene, with lower counts of other polymers including the biopolymer poly(lactic acid). Particle size and mass distributions were parameterized by means of power law distributions, which allowed performing estimations of the concentration of smaller particles provided the same scaling parameter of the power law applies. The calculated total mass concentration of the identified MPs was 45.5 ng/L. The observed size distribution of MPs allowed an estimation for the concentration of nanoplastics (< 1 µm) well below the ng/L range; higher concentrations are not consistent with scale invariant fractal fragmentation. Our findings showed that MPs in the drinking water sampled in this work do not represent a significant way of exposure to MPs and would probably pose a negligible risk for human health.

Metal contents and size distributions of brake and tire wear particles dispersed in the near-road environment

Traffic related non-tailpipe particulate matter emissions can rival the continuously decreasing tailpipe emissions in modern fleets. Non-tailpipe emissions have become the dominating source of traffic emissions in California already. This study measured ambient PM2.5 and PM10 concentrations at near road environments for two major highways in California, I-5 in Anaheim and I-710 in Long Beach. A total of 51 elements were measured from filter samples collected over four-hour intervals for a two-week period in the winter of 2020 before the statewide lockdown by the COVID-19 pandemic. Iron was the most abundant element in ΔPM10 (differences between downwind and upwind sites), contributing to 30 % and 24 % of total measured elements in ΔPM10 at the I-5 and I-710 locations, respectively. Iron correlated highly with other brake wear markers (e.g., titanium, copper, barium, manganese, and zirconium) with coefficient of determination (r2) ranging from 0.67 to 0.90 in both PM2.5 and PM10. Silicon was the second most abundant element, contributing to 21 % of total measured elements in ΔPM2.5 and ΔPM10. Silicon showed strong correlations with crustal elements such as calcium (r2 = 0.90), aluminum (r2 = 0.96), and potassium (r2 = 0.72) in ΔPM2.5, and the correlations were even higher in ΔPM10. Barium had a weak correlation with zinc, a commonly used maker for tire wear, with r2 = 0.63 and r2 = 0.11 for ΔPM10 at the I-5 and I-710 locations respectively. Barium showed a positive correlation with crosswind speed and could serve as a good brake wear PM marker. Hourly PM2.5 concentrations of iron and zinc showed cyclic peaks from 0800 to 1000 h at I-5 during weekdays. Particle mass distributions showed peaks near ~7 μm, while particle number distributions showed peaks near 2.1 μm and 6.5 μm, respectively. This is consistent with brake wear and road dust size ranges previously reported.

Analysis of the overall pressure balance loop for a methanol-to-olefins dual fluidized bed reactor-regenerator

Development of a comprehensive reactor model is of paramount importance for design and scale-up of methanol-to-olefins (MTO) process in a dual fluidized bed reactor (DFB). These models must integrate suitable reaction kinetic expressions with hydrodynamic models properly descriptive of gas-solid contact in fluidized bed reactors. In this modeling study, our previously developed kinetic models of MTO fluidized bed reactor and regenerator are coupled with overall mass, energy and pressure balances to ensure smooth circulation of catalyst particles between the two fluidized beds. This integrated model was then applied to determine geometric dimensions of a demo-scale MTO DFB configuration and to obtain the mass distribution of catalyst particles throughout the entire system including the pipes connecting the two reactors. Our model is capable of being integrated into simulation software such as Aspen Plus for plant-wide optimization and scale-up studies.

Clusters of heavy particles in two-dimensional Keplerian turbulence

Protoplanetary disks are gaseous systems in Keplerian rotation around young stars, known to be turbulent. They include a small fraction of dust from which planets form. In the incremental scenario for planet growth, the formation of kilometer-size objects (planetesimals) from pebbles is a major open question. Clustering of particles is necessary for solids to undergo a local gravitational collapse. To address this question, the dynamic of inertial particles in turbulent flows with Keplerian rotation and shear is studied. Two-dimensional direct numerical simulations are performed to explore systematically two physical parameters: the rotation rate, which depends on the distance to the star, and the particle response time, which relates to their size. Shear is found to drastically affect the characteristics of the turbulent flow destroying cyclones and favoring the survival of anticyclones. Faster Keplerian rotation enhances clustering of particles. For intermediate sizes, particles concentrate in anticyclones. These clusters form in a hierarchical manner and merge together with time. For other parameter values, solids concentrate on fractal sets that get more singular with rotation. The mass distribution of particles is then found to be multifractal with small dimensions at large orders, intriguing for triggering their gravitational collapse. Such results are promising for a precise description and better understanding of planetesimal formation.

Characterization of aerosolized particles in effluents from carbon fibre composites incorporating nanomaterials during simultaneous fire and impact

This work investigates the aerosols emitted from carbon fibre-reinforced epoxy composites (CFC) incorporating nanomaterials (nanoclays and nanotubes), subjected to simultaneous fire and impact, representing an aeroplane or automotive crash. Simultaneous fire and impact tests were performed using a previously described bespoke testing methodology with the capability to collect particles released from the front/back faces of the impacted composites plus the effluents. In this work the methodology has been further developed by connecting the Dekati Low Pressure Impactor (DLPI) and Mini Particle Sampler (MPS) sampling system in the extraction chimney. The aerosols emitted have been characterized using various devices devoted to the analysis of aerosols. The influence of the nanoadditives in the matrix on the number concentration and the size distribution of airborne particles produced, was studied with a cascade impactor in the 5 nm–10 μm range. The morphology of the separated soot fractions was examined by SEM. The measurement of aerodynamic size of particles that can deposit in human respiratory tract indicate that 75% of the soot and particles released from CFC could deposit in the lungs reaching the bronchi region at a minimum. There was however, a minimal difference between the number particle concentrations or particle-size mass distribution of particles from CFC and CFC containing nanoadditives. Moreover, no fibres were found in the effluents.

Impacts of Cloud‐Processing on Ice Nucleation of Soot Particles Internally Mixed With Sulfate and Organics

AbstractSoot particles are one of the major aerosol components (in particle number concentration) in the troposphere and can impact cirrus formation. Depending on their physicochemical properties, soot particles can nucleate ice in the cirrus regime via pore condensation and freezing (PCF) at a lower ice saturation threshold than that of the homogeneous freezing of solution droplets. Soot aerosol undergoing multiple cloud cycles can change its porosity and surface wettability, thus modulating its PCF ability. In this study, organic‐rich and ‐lean size‐selected propane flame soot particles were coated with different thicknesses of sulfuric acid (H2SO4) and exposed to thermodynamic conditions under 228 K and relative humidity with respect to water 104% to simulate contrail formation. Ice‐activated soot particles from the mimicked contrail were sublimated before being tested for ice nucleation (IN) at T ≤ 233 K. Additionally, soot particle size and mass distribution as well as morphology were characterized. The results demonstrate that the increase in mesopore availability induced by cloud‐processing plays a key role in regulating soot IN. All cloud‐processed soot become more compacted, however, only if more PCF relevant mesopores are generated, can the compacted soot exhibit promoted IN. If a H2SO4 coating and/or enriched organics occupy the pore volume, inhibition of PCF is observed for the cloud‐processed soot. Notably, a thick H2SO4 coating enhances the PCF of 400 nm organic‐lean soot particles because the partially engulfed but collapsed soot‐core may have new mesopores produced by compaction. Therefore, the mesopore abundance plays the key role in evaluating aged soot IN ability.