Aerosol Generation Research Articles

The investigation of traceable preparation technique of submicron particle number concentration standards in liquids

The concentration of particles at the nano- and submicron-meter scale in liquid is crucial in multiple fields including the biomedical and semiconductor industry. However, there is still a lack of metrological standards or Certified Reference Materials (CRMs) for liquid-borne particle number concentration (PNC) which could be traceable to the International System of Units (SI). To address this issue, a quantitative and value-traceable preparation technique for liquid-borne particle number concentration CRMs (PNC-CRMs) in a submicron-meter scale based on controllable aerosol generation and collection was developed in this study. In this technique, by using commercial differential electrostatic mobility analyzer (DMA) and calibrated condensation particle counter (CPC), monodisperse aerosol particle with known concentration was initially generated. Then for quantitatively transforming the aerosol particles to the liquid, an aerosol particle collection system was designed and developed by hydrodynamic (CFD) simulations and experiment conducting, and crucial parameters of the collection system, e.g. the nozzle diameter of the aerosol particle outlet, the distance from the nozzle to the liquid surface, and the state of the liquid interface, were investigated and optimized. Under the optimized collected parameters, the collection efficiency for aerosol particles of the newly-developed system could reach over 90%. Because the PNC in aerosol is SI-traceable, combined with the obtained collection efficiency and collection time, the PNC in the collection liquid with could be obtained finally and trace to SI unit. Using this technique, two kinds of PNC-CRMs with nominal sizes of 100 and 500 nm were developed successfully, where, certified values were (7–9) × 106 particles/mL and 1.7 × 106 particles/mL, and standard uncertainties are 4.2%.

Potential effects of aerosol generation and transmission during bedside endoscope cleaning.

Airborne transmission is among the most frequent types of nosocomial infection. Recent years have witnessed frequent outbreaks of airborne diseases, such as severe acute respiratory syndrome (SARS) in 2002, Middle East respiratory syndrome (MERS) in 2012, and coronavirus disease 2019 (COVID-19), with the latter being on the rampage since the end of 2019 and bringing the effect of aerosols on health back to the fore (Gralton et al., 2011; Wang et al., 2021). An increasing number of studies have shown that certain highly transmissible pathogens can maintain long-term stability and efficiently spread through aerosols (Leung, 2021; Lv et al., 2021). As reported previously, influenza viruses that can spread efficiently through aerosols remain stable for a longer period compared to those that cannot. The World Health Organization (WHO) has stated that aerosol-generating procedures (AGPs) play an important role in aerosol transmission in hospitals (Calderwood et al., 2021). AGPs, referring to medical procedures that produce aerosols, including dental procedures, endotracheal intubation, sputum aspiration, and laparoscopic surgeries, have been reported to be significantly associated with an increased risk of nosocomial infection among medical personnel (Hamilton, 2021).

Investigation of Factors Influencing the Effectiveness of Deformable Nanovesicles for Insulin Nebulization Inhalation.

Nebulized inhalation offers a noninvasive method for delivering drugs to treat both local respiratory and systemic diseases. In this study, insulin was used as a model drug to design a series of deformable nanovesicles (DNVs) with key quality attributes, including particle size, deformability, and drug load capacity. We investigated the effects of these properties on aerosol generation, macrophage phagocytosis, and bloodstream penetration. The results showed that deformability improved nebulization performance and reduced macrophage phagocytosis, benefiting local and systemic delivery. However, the advantage of DNVs for transmembrane penetration was not evident in the alveolar epithelium. Within the size range of 80-490 nm, the smaller the particle size of IPC-DNVs, the easier it is to evade clearance by macrophages and the more effective the in vivo hypoglycemic efficacy will be. In the drug load range of 3-5 mg/mL, a lower drug load resulted in better hypoglycemic efficacy. The area above the blood glucose decline curve with time (AAC) of nebulized DNVs was 2.32 times higher than that of the insulin solution, demonstrating the feasibility and advantages of DNVs in the pulmonary delivery of biomacromolecule drugs. This study provides insights into the construction and formulation optimization of pulmonary delivery carriers.

Harmful and Potentially Harmful Constituents in E-Liquids and Aerosols from Electronic Nicotine Delivery Systems (ENDS).

In 2012, the U.S. Food & Drug Administration (FDA) published an established list of 93 harmful and potentially harmful constituents (HPHCs) targeting four tobacco product types (cigarettes, cigarette tobacco, roll-your-own tobacco, smokeless tobacco). In 2016, the FDA finalized the deeming rule to regulate electronic nicotine delivery systems (ENDS). However, knowledge gaps exist regarding whether certain HPHCs are present in ENDS e-liquids and aerosols. We identified and addressed these gaps by conducting literature searches and then experimentally quantifying HPHCs in the e-liquid and aerosol of 37 ENDS brands based on gaps in the literature. The literature searches identified 66 e-liquid HPHCs and 68 aerosol HPHCs that have limited to no information regarding the quantifiability of these constituents. A contracted ISO 17025 accredited laboratory performed the HPHC quantifications. The availability of validated analytical methods in the contracted laboratory determined the HPHCs included in the study scope (63/66 for e-liquids, 64/68 for aerosols). Combining the results from the quantifications and literature searches, 36 (39%) and 34 (37%) HPHCs were found quantifiable (≥limit of quantification [LOQ]) in ENDS e-liquids and aerosols, respectively, with 25 HPHCs being quantifiable in both matrices. Quantifiability results imply potential HPHC transfers between matrices, leaching from components, or formations from aerosol generation. The study results can inform the scientific basis for manufacturers and regulators regarding regulatory requirements for HPHC reporting. The HPHC quantities can also inform evaluations of the public health impact of ENDS and public communications regarding ENDS health risks.

Antisense oligonucleotides and their technical suitability to nebulization

In vivo studies investigating the inhalative efficacy of biotherapeutics, such as nucleic acids, usually do not perform an aerosolization step, rather the solution is directly administered into the lungs e.g. intratracheally. In addition, there is currently very little information on the behavior of nucleic acid solutions when subjected to the physical stress of the nebulization process.In this study, the aim was to assess the technical suitability of Locked Nucleic Acids (LNAs), as a model antisense oligonucleotide, towards nebulization using two commercially available nebulizers. A jet nebulizer (Pari LC Plus) and a vibrating mesh nebulizer (Aerogen Solo) were employed and solutions of five different LNAs investigated in terms of their physical and chemical stability to nebulization and the quality of the generated aerosols. The aerosol properties of the Aerogen Solo were mainly influenced by the viscosity of the solutions with the output rate and the droplet size decreasing with increasing viscosity. The Pari LC Plus was less susceptible to viscosity and overall the droplet size was smaller. The LNAs tolerated both nebulization processes and the integrity of the molecules was shown. Chemical stability of the molecules from the Aerogen Solo was confirmed, whereas aerosol generation with the Pari LC Plus jet nebulizer led to a slight increase of phosphodiester groups in a fully phosphorothiolated backbone of the LNAs. Overall, it could be shown that nebulization of different LNAs is possible and inhalation can therefore be considered a potential route of administration.

Evaluation of dental emergency during the COVID-19 pandemic in the Social Rehabilitation Centre of San Francisco Kobén (Campeche, Mexico).

During the COVID-19 pandemic, access to dental treatment by persons deprived of their liberty (PPL) was affected due to dentist-patient proximity and the risk of generation of aerosols in dental procedures and treatments. The risks of infection for oral health personnel are considered high, mainly from cross-infection between patients. Differentiate between a true and false dental consultation emergency during the SARS-CoV-2 outbreak for a better and effective screening of inmates of the Social Rehabilitation Center (CERESO) of San Francisco Kobén (Campeche, Mexico). An observational, cross-sectional, descriptive, and prospective study was designed for a sample of 100 inmates of the CERESO San Francisco Kobén, the data was collected in the prison's dental office, the participants signed a letter of informed consent to be voluntarily included in the study during the SARS-CoV-2 outbreak. The questionnaire "Assessment of a true Dental Emergency" previously validated for the Mexican population was applied, the personnel was standardized and an intra- examiner and inter-examiner reliability of k = 0.98 was obtained. To prepare the database and the analysis of the information collected, the Statistical Package for Social Science v. 21 (SPSS v.21) was used. When evaluating emergencies at the dental clinic, 84% were determined according to the instrument as a false emergency and 16% were a true emergency. In the population of CERESO of San Francisco Kobén, the figures for medical-dental care show that inmates face a proportionally low dental morbidity-mortality.

Experience with flexible bronchoscopy for noncoronavirus disease of 2019indications in pediatric patients during the coronavirus disease of 2019pandemic.

Flexible bronchoscopy (FB) poses a risk ofsevere acute respiratory syndrome coronavirus 2(SARS-CoV-2) transmission due to aerosol generation. This study aimed to assess the utilization, indications, outcomes, and safety of FB in pediatric patients for noncoronavirus disease of 2019 (COVID-19) reasons during the pandemic. We retrospectively analyzed pediatric patients who underwent FB for non-COVID-19 indications at a tertiary children's hospital's pulmonary clinic during the COVID-19 pandemic. Patients showed no COVID-19 symptoms and tested negative for SARS-CoV-2 by real-time polymerase chain reaction (PCR) of nasopharyngeal and throat swabs within 24 h before the procedure. FBs were conducted in the operating room, with healthcare professionals (HCPs)wearing personal protective equipment, including medical N95 masks, gloves, gowns, and eye protection. Between March 2020 and April 2022, 167 pediatric patients underwent FB for non-COVID-19 indications. Common indications included foreign body aspiration (22.7%), stridor (10.1%), and atelectasis (8.9%). No COVID-19 symptoms were observed in patients on the 1st and 10th days post-FB. During the 1-month follow-up, 52 patients underwent SARSCoV-2 PCR testing, and one patient tested positive in the third week after the procedure. None of the HCPs in the FB team experienced COVID-19 symptoms or tested positive for SARS-CoV-2. A bronchoscopy protocol with safety precautions minimized the risk of COVID-19 transmission, allowing safe FB performance for non-COVID-19 indications in pediatric patients during the pandemic. The experience gained in FB during COVID-19 is valuable for similar situations in the future.

Rapid Primary Sulfate Aerosol Generation Observed With OP‐FTIR in the Eruptive Plume of the Fagradalsfjall Basaltic Eruption, Iceland, 2021

AbstractOpen‐Path Fourier‐Transform Infrared (OP‐FTIR) absorption spectroscopy is a powerful method for remote characterization of volcanic plume composition from safe distances. Many studies have used it to examine the composition of volcanic gas emitted at the surface, which is influenced by initial volatile contents and magma ascent/storage processes, and help to reveal the dynamics controlling surface activity. However, to evaluate the health hazard threats associated with volcanic emissions and their potential impact on wider atmospheric conditions, near‐source particle measurements are also key. Here we present a forward model and fitting algorithm which allows quantification of particle size and abundance. This was successfully applied to radiometrically uncalibrated OP‐FTIR spectra collected with a highly dynamic radiation source during the Fagradalsfjall eruption, Iceland, on 11 August 2021. Quantification of plume temperatures ranging from 350 to 650 K was essential to characterize the emission‐absorption behavior of SO2, enabling retrievals of particulate matter in the thermal infrared spectral window (750–1250 cm−1) in each spectrum. For the first time, we observe the rapid formation of primary aerosols in young plumes (only a few seconds old) with OP‐FTIR. Temperature‐dependent SO2/SO42− molar ratios range from 100 to 250, consistent with a primary formation mechanism controlled by cooling and entrainment of atmospheric gases. This novel aerosol spectrum retrieval opens new frontiers in field‐based measurements of sulfur partitioning and volcanic plume evolution, with the potential to improve volcano monitoring and quantification of air quality hazard assessments.

Cationic surfactant-assisted foam fractionation enhances the removal of short-chain perfluoroalkyl substances from impacted water

Several studies have demonstrated that air-bubbling and foam fractionation techniques can efficiently remove long-chain PFAS from contaminated water. However, removing short-chain PFAS is challenging due to its lower surface activity and inability to form self-assembly structures at the air-water interface. In this study, we tested various additives, including salts, surfactants, and polymers, to improve short-chain PFAS (e.g., perfluorobutanesulfonic acid (PFBS) and perfluorobutanoic acid (PFBA)) removal in non-foaming solutions using a bench-scale system. We found that in the presence of cetyltrimethylammonium chloride (CTAC) and salt, air-bubbling can significantly remove 0.5 μg L−1 of PFBS and PFBA in deionized water by >99% (15 min) and 81% (60 min), respectively. The decline of surface tension and the formation of thin foam-like layers during bubbling, controlled by the concentration of CTAC, significantly improved the removal of short-chain PFAS. Adding anionic and neutral surfactants showed no removal of short-chain PFAS during bubbling, suggesting the importance of the electrostatic interactions between short-chain PFAS and the cationic CTAC. We observed a 1:1 M ratio between CTAC and PFBS removed from the solution, suggesting the formation of ion pairs in the solution and enhancing the surface activity of the overall neutral (PFAS-CTAC) complex. A mass balance of the system revealed that the primary mechanism by which PFAS was removed from non-foaming waters was through aerosol generation (70−100%). Using the optimized condition, PFAS mixtures (short- and long-chain PFAS, including five recently regulated PFAS by USPEA, 2 nM each) in deionized water and natural groundwater were successfully removed to below detection (>99% removal; <2 ng L−1), except for PFBA (25−73% removal). These results provide an improved understanding of the mechanism by which PFAS is removed during foam fractionation and highlight the need for capturing aerosols enriched with PFAS to prevent secondary contamination.

Effect of solute concentration on the number of NaCl particles generated by millimeter- and micron-sized droplets

Salt particles generated by aerosol generator are commonly used in air filtration test. As a common phenomenon, the number of generated particles increases with the salt concentration in the atomization solution. Thus far, the dependence of the particle number on the concentration of the atomization solution is not fully understood. In this study, two hypotheses were proposed to explain this phenomenon: i) a single droplet generates multiple solid particles, and the generated particle number is influenced by the salt concentration, and ii) the original droplet number increases with an increase in the salt concentration of the atomization solution. By observing the particle formation process of the levitated millimeter-scale NaCl droplet, one droplet was found to generate one particle in free air. However, whether these results are applicable to micrometer-scale droplets remains to be determined. In situ measurements were performed to detect the size distributions of the original droplets generated by the atomization solutions with various salt concentrations. A more concentrated atomization solution induced a higher number of original droplets. Particle formation patterns of droplets on glass substrates and filaments were demonstrated. Traditional observation methods for droplet drying are unsuitable for studying the particle formation of atomized droplets because of the large difference in droplet size and the existence of external forces.

Minimal intervention dentistry and reduction of aerosol generation of Covid-19: evidence-based recommendations

Minimal intervention dentistry and reduction of aerosol generation of Covid-19: evidence-based recommendations

Variation in aerosol generation by surgical modality during oropharyngeal and laryngeal surgery.

The objectives were to determine the surgical modality with the lowest aerosol and droplets generated by commonly used modalities in oropharyngeal and laryngeal surgery. A simulation of oropharyngeal and laryngeal surgery was set up using fresh sheep heads. Four common surgical modalities were utilized: cold steel, electrocautery, coblation, and microdebrider. The resultant aerosol generated was evaluated using two measurement modalities at two key positions in the theater. (1) DustTrak Pro Aerosol Monitor was used to measure the concentration of particles. (2) Fluorescein dye coated on the oropharynx and larynx, and the resultant scatter on paper. Electrocautery and coblation produced statistically significant increases in the concentration of aerosols (p < .001). Microdebrider and cold steel instrumentation produced the least aerosols. No measurable fluorescein droplets were noted for all four modalities. Electrocautery and coblation produced higher concentrations of aerosols. Mitigation factors should be considered with instruments with increased aerosolization. These modalities show low droplet-related infection risk.

A Comparative Investigation of Aerosol Generation and Exposure Risk During Access Cavity Preparation With or Without Rubber Dam Application.

Aerosols generated during dental procedures have taken the forefront of discussion in dentistry. Due to the nature of their work, dental professionals face a significant risk of exposure to various biological hazards, such as saliva, blood, aerosols, and droplets. Aerosols, which are tiny particles with a diameter of less than 50µm, have a unique property that allows them to stay suspended in the air for extended periods. This is primarily due to their small size and lightweight naturewhich makes them highly susceptible to air currents and prevents them from quickly settling down. As a result, these aerosols can linger in the atmosphere, creating a potential risk for respiratory infections. The aim is to evaluate and compare the efficacy of rubber dams in preventing aerosols generated cross-contamination. This in-vivo experimental study comprised 60 individuals who were suggested for root canal treatment in the mandibular first permanent molar tooth. The passive air sampling technique using "settle plates" was applied to investigate microbial fallout during access opening with and without rubber dam application. Sheep blood agar plates were used to do the colony forming unit (CFU) count. All patients were randomly divided into two groups comprising30 patients each based on usage of rubber dam application or not, i.e., Group I: Without rubber dam application and Group II: With rubber dam application. Using a rubber dam while performing an endodontic procedure significantly impacts decreased aerosol generation at 0.5-mand 2-mdistances than its counterpart with a p-value < 0.01. Using a rubber dam during endodontic procedures reduces the likelihood of aerosol generation, thereby decreasing the risk of cross-contamination and lowering the susceptibility of dental professionals to respiratory illnesses.

Spark Discharge Aerosol-Generated Copper-Based Nanoparticles: Structural & Optical Properties; Application on the Antiviral (SARS-CoV-2) and Antibacterial Improvement of Face Masks.

Nanoparticle formation by Spark Discharge Aerosol Generation offers low-cost fabrication of nanoparticles, without the use of chemicals or vacuum. It produces aerosol particles of a few nanometers in size with high purity. In this work, copper-based -CuO (tenorite) and Cu- nanoparticles are produced, characterized and used to modify face mask air filters, achieving the introduction of antibacterial and antiviral properties. A range of characterization techniques have been employed, down to the atomic level. The majority of the particles are CuO (of a few nanometers in size that agglomerate to form aggregates), the remainder being a small number of larger Cu particles. The particles were deposited on various substrates, mainly fiber filters in order to study them and use them as biocidal agents. On face masks, their antibacterial activity against Escherichia coli (E.coli) results in a 100 % decrease in bacteria cell viability. Their antiviral activity on face masks results in a 90 % reduction of the Severe Acute Respiratory Syndrome Corona Virus 2 (SARS-CoV-2) viability, 15 minutes post the application of the virus stock solution. This highlights the effectiveness of this approach, its simplicity, its low cost and its excellent environmental credentials.

Source identification of ultrafine particulate matter and ammonia emissions in the metropolitan area

Previous studies have estimated the sources of particulate matter in the atmosphere. Among these, studying the sources of secondary aerosols harmful to human health is important. However, there is a lack of research on ammonia (NH3), a precursor to secondary aerosol formation. This study uses positive matrix factorization (PMF) model and conditional bivariate probability function (CBPF) model to estimate the sources of particulate matter and ammonia. The results showed that about 40% of the PM2.5 mass at both sites was attributable to secondary aerosol. To estimate the emission sources of ammonia that contribute to the generation of secondary aerosols, CBPF was utilized to model and compare the emission characteristics of categorized pollution sources and ammonia, and it was found that SMA had similar emission trends to industry, road dust, oil combustion, and biomass combustion, while GRA had similar emission trends to oil combustion and vehicle (diesel). Considering the results from these two regions, ammonia in the metropolitan area is more likely to be emitted from daily activities than from long distances. The study results demonstrate the major role of secondary aerosols on ambient PM2.5 concentrations and can help develop effective management strategies and policies for air pollution mitigation.

Determining the ultraviolet radiation dose experienced by aerosols using ultraviolet-sensitive dyes

Abstract. ​​​​​​​The application of ultraviolet (UV)-light-based air disinfection methods holds promise but also presents several challenges. Among these, the quantitative determination of the required UV radiation dose for aerosols is particularly significant. This study explores the possibility of determining the UV dose experienced by aerosols without the use of virus-containing aerosols, circumventing associated laboratory safety issues. To achieve this, we developed a model system comprised of UV-sensitive dyes dissolved in di-ethyl-hexyl-sebacate (DEHS), which facilitates the generation of non-evaporating and UV-degradable aerosols. For the selection of UV-sensitive dyes, 20 dyes were tested, and 2 of them were selected as being the most suitable, according to several selection criteria. Dye-laden aerosol droplets were generated using a commercial aerosol generator and subsequently exposed to UV-C radiation in a laboratory-built UV irradiation chamber. We designed a low-pressure impactor to collect the aerosols pre- and post-UV exposure. Dye degradation, as a result of UV light exposure, was then analyzed by assessing the concentration changes in the collected dye solutions using a UV-visible spectrophotometer. Our findings revealed that a UV dose of 245 mW s cm−2 resulted in a 10 % degradation, while a lower dose of 21.6 mW s cm−2 produced a 5 % degradation. In conclusion, our study demonstrates the feasibility of using aerosol droplets containing UV-sensitive dyes to determine the UV radiation dose experienced by an aerosol.

Construction and Investigation of a Filtration Efficiency Test System for High-Efficiency Filter Materials Based on Mass Concentration

Protection from nuclear biochemical aerosol and air pollution pays attention to aerosol mass concentration. The concentration of upstream aerosol of the commonly used filtration efficiency detection device for high-efficiency filter materials is low, making it insufficient for detecting the filtration efficiency of high-efficiency filter materials. This study designed and built a set of filtration efficiency detection devices for high-efficiency filter materials based on mass concentration. By adjusting the oil bath temperature, injection pressure, the degree of spiral-separator separation, as well as the number and size of nozzles, we investigated the effects of each condition on the concentration and particle size distribution of aerosol generation. As a result, the oil mist generator of the device can stably generate high-concentration aerosol with a mass concentration of up to 1587.9 mg/m3 and a number concentration of up to 107–108 P/cm3. The high-concentration aerosol generated can meet the E11–U15 filter material performance requirements.

Resolving the Loss of Intermediate-Size Speech Aerosols in Funnel-Guided Particle Counting Measurements

Modeling of airborne virus transmission and protection against it requires knowledge of the amount of biofluid emitted into the atmosphere and its viral load. Whereas viral concentrations in biofluids are readily measured by quantitative PCR, the total volume of fluids aerosolized during speaking, as measured by different researchers using various technologies, differs by several orders of magnitude. We compared collection methods in which the aerosols first enter into a low-humidity chamber either by direct injection or via commonly used funnel and tubing arrangements, followed by standard optical particle sizer measurement. This “collect first, measure later” approach sacrifices the recording of the temporal correlation between aerosol generation and sound types such as plosives and vowels. However, the direct-injection mode prevents inertia deposition associated with the funnel arrangements and reveals far more intermediate-size (5–20 μm in diameter) particles that can dominate the total mass of ejected respiratory aerosol. The larger aerosol mass observed with our method partially reconciles the large discrepancy between the SARS-CoV-2 infectious dose estimated from superspreader event analyses and that from human challenge data. Our results also impact measures to combat airborne virus transmission because they indicate that aerosols that settle faster than good room ventilation rates can dominate this process.

Glucose Enhances Salinity-Driven Sea Spray Aerosol Production in Eastern Arctic Waters.

Sea spray aerosols (SSA) greatly affect the climate system by scattering solar radiation and acting as seeds for cloud droplet formation. The ecosystems in the Arctic Ocean are rapidly changing due to global warming, and the effects these changes have on the generation of SSA, and thereby clouds and fog formation in this region, are unknown. During the ship-based Arctic Century Expedition, we examined the dependency of forced SSA production on the biogeochemical characteristics of seawater using an on-board temperature-controlled aerosol generation chamber with a plunging jet system. Our results indicate that mainly seawater salinity and organic content influence the production and size distribution of SSA. However, we observed a 2-fold higher SSA production from waters with similar salinity collected north of 81°N compared to samples collected south of this latitude. This variability was not explained by phytoplankton and bacterial abundances or Chlorophyll-a concentration but by the presence of glucose in seawater. The synergic action of sea salt (essential component) and glucose or glucose-rich saccharides (enhancer) accounts for >80% of SSA predictability throughout the cruise. Our results suggest that besides wind speed and salinity, SSA production in Arctic waters is also affected by specific organics released by the microbiota.

Aerosol drug therapy in critically ill patients (Aero-in-ICU study): A multicentre prospective observational cohort study.

In recent years, a significant understanding of delivering optimal aerosol therapy and the availability of various drugs and devices have led to an increase in its use in clinical practice. There are only a few studies available regarding their use in critically ill patients from a few parts of the world. We aimed to study the practice pattern of aerosol therapy in critically ill patients from Indian intensive care units (ICUs). After ethical approval, this multi-centric prospective observational study was performed over a study period of four weeks. Newly admitted adult patients considered who had an artificial airway and/or ventilation (including non-invasive). Patients were followed up for the next 14 days or until ICU discharge/death (whichever came first) for details of each aerosol therapy, including ongoing respiratory support, drug type, and aerosol-generating device. From the nine participating centers across India, 218 patients were enrolled. Of 218 enrolled patients, 72.48% received 4884 aerosols with 30.91 ± 27.15 (95%CI: 26.6-35.1) aerosols per patient over 1108 patient days. Approximately 62.7% during IMV, 30.2% during NIV, 2.3% in spontaneously breathing patients with an artificial airway during weaning, and 4.7% were given without an artificial airway after weaning or decannulation. In 59%, a single drug was used, and bronchodilators were the most frequent. The jet nebulizer was the most common, followed by the ultrasonic and vibrating mesh aerosol generator. The ventilator setting was changed in only 6.6% of the aerosol sessions with IMV and none with NIV. Aerosol therapy is frequently used with a wide variation in practices; bronchodilators are the most commonly used drugs, and jet nebulizers are the most widely used.