To survey 30 patients aged 15-65 years with acute severe asthma. They were randomized into one of three different groups: group(A): reiceived salbutamol solution via a nebulizer impelled with oxygen; group (B): received Salbutamol solution via an air compressor-driven nebulizer; and group (C): received Salbutamol via a Metered-dose inhaler attached to a value aerosol holding chamber (Volumatic). After the 6 hours treatment, PEF (peak exhale flow) and other parameters improved significantly in 27 patients. No patient discontinued the trial or transferred to the intensive unit and no cardiovascular adverse events were reported in the study groups. These data showed that the three delivery methods were appropriate to treat subjects with acute severe asthma, however the metered dose inhaler (with holding chamber) was the best choice in the recent medical condition of Vietnam
Asthma ; Aerosols ; Albuterol ; Therapeutics ;

A study was conducted to investigate the blood lead and zinc protoporphyrin(ZPP) concentrations of the underground parking lot workers who exposed to vehicular exhaust aerosols which contained lead. The blood samples were collected from 25 study subjects of underground parking lot and from 33 controls in Taegu, from July to October, 1997. And also the related factors to the blood lead and ZPP concentrations were investigated. Blood lead concentration and ZPP concentration were measured by flameless furnace atomic absorption spectrophotometer (IL.551) and hemetofluorometer, respectively. The mean blood lead concentrations of study subjects and controls were 23.10+/-20.77microgram/dl and 12.99+/-12.71microgram/dl, respectively(p<0.05), and the mean blood ZPP concentrations of study subjects and controls were 40.72+/-9.46microgram/dl and 38.21+/-10.97microgram/dl, respectively. No significant correlations were observed between the blood lead concentration of the study subjects and their job duration and between blood ZPP concentration of the study subjects and their job duration. There were no statistically significant differences in the blood lead concentration and the blood ZPP concentration of smokers and nonsmokers. In multiple regression analysis on blood lead concentration of the study subjects and controls, occupation was a only significant dependent variable. In case of bood ZPP concentration, age was a only significant dependent variable in the study subjects and controls.
Absorption ; Aerosols ; Daegu ; Occupations ; Zinc

Taxi drivers are exposed to vehicular exhaust aerosols which are a major source of atmospheric lead pollution in Korea where lead additives are incorporated in petrol. To investigate the blood lead concentration, their correlation factors and influences on taxi drivers, samples were collected from 90 taxi drivers who were living in the Taegu City, during August, 1989. Blood lead concentration was estimated by the atomic absoption spectrophotometer (IL.551) equipped with flameless furnace atomizer (IL.665). The results were analyzed statistically and compared with control group were 26.34 +/- 6.53 microgram/dl and 20.77 +/- 4.80 microgram/dl respectively (p<0.01). No significant correlation was observed between the blood lead concentration of taxi drivers and driver career (r=0.093). There were no difference of statistical significance in the blood lead concentration of smokers and nonsmokers.
Aerosols ; Daegu* ; Korea* ; Nebulizers and Vaporizers

Objective: To explore the occupational protective effect of different protective devices on the operators during manual cleaning and oiling of dental handpieces, and to provide a basis for the selection of appropriate protective methods. Methods: From November 2020 to December 2021, 20 high-speed dental handpieces of the same brand were selected and randomly divided into disposable protective bag group and small aerosol safety cabinet group by drawing lots, with 10 in each group. After recording the model, they were distributed to the clinical fixed consulting room for use, and were collected by specially-assigned personnel every day for manual cleaning under the protection of the two devices. By measuring the number of airborne colonies, the concentrations of particulate matter and the satisfaction of operators, the occupational protection effect of the two protective devices on operators was evaluated. Results: Under the protection of the two devices, the average number of airborne colonies after operation was less than 1 CFU/ml. When no protective device was used, the number concentration of particulate matter produced during operation was (21595.70±8164.26) pieces/cm(3). The number concentrations of particles produced by disposable protective bag group [ (6800.24±515.05) pieces/cm(3)] and small aerosol safety cabinet group [ (5797.15±790.50) pieces/cm(3)] were significantly lower than those without any protective device (P<0.001). The number concentration of particle matter of small aerosol safety cabinet group was significantly lower than that of disposable protective bag group (P<0.001). In the satisfaction evaluation of operators, small aerosol safety cabinet group [ (3.53±0.82) points] was significantly better than disposable protective bag group [ (2.23±1.10) points] (P<0.001) . Conclusion: The use of small aerosol safety cabinet during manual cleaning and oiling of dental handpieces has good protective effect, superior safety performance and strong clinical applicability, and has advantages in occupational protection of clinical operators.
Aerosols ; Particulate Matter ; Protective Devices

BACKGROUND: Workers in the microbiology laboratories are continuously exposed to the risk of laboratory-associated infections. Tuberculosis (TB) is a frequent laboratory-acquired infection owing to production of cough-generated aerosols with ease and high infectivity of Mycobacterium tuberculosis. This study aims to investigate the current situation of biosafety in Korean TB laboratories. METHODS: We conducted a nationwide survey of laboratories in hospitals conducting TB tests using questionnaires about their facility and management standards. RESULTS: We analyzed data from 52 hospitals nationwide that have a capacity of 100–2,000 beds, of which only two laboratories conduct high risk drug-susceptibility testing on cultured isolates among other test items, whereas six laboratories perform only direct sputum-smear microscopy. The remaining laboratories performed moderate-risk activities/tests, like sample processing for culture. In the majority of these laboratories, there are laboratory medicine specialists who are fully in charge of health checkup programs for laboratorians. The facility and management standards vary widely according to the size of the hospital and risk of TB tests. CONCLUSIONS: Our survey results about the current situation of TB laboratories could be useful as baseline data for preparing biosafety guidelines for all TB laboratories in Korea.
Aerosols ; Korea* ; Microscopy ; Mycobacterium tuberculosis ; Specialization ; Tuberculosis*

BACKGROUND: Surfactant-containing water sprays are commonly used in coal mines to collect dust. This study investigates the dust collection performance of different surfactant types for a range of coal dust particle sizes and charges. METHODS: Bituminous coal dust aerosol was generated in a wind tunnel. The charge of the aerosol was either left unaltered, charge-neutralized with a neutralizer, or positively- or negatively-charged using a diffusion charger after the particles were neutralized. An anionic, cationic, or nonionic surfactant spray or a plain water spray was used to remove the particles from the air flow. Some particles were captured while passing through spray section, whereas remaining particles were charge-separated using an electrostatic classifier. Particle size and concentration of the charge-separated particles were measured using an aerodynamic particle sizer. Measurements were made with the spray on and off to calculate overall collection efficiencies (integrated across all charge levels) and efficiencies of particles with specific charge levels. RESULTS: The diameter of the tested coal dust aerosol was 0.89 μm ± 1.45 [geometric mean ± geometric standard deviations (SD)]. Respirable particle mass was collected with 75.5 ± 5.9% (mean ± SD) efficiency overall. Collection efficiency was correlated with particle size. Surfactant type significantly impacted collection efficiency: charged particle collection by nonionic surfactant sprays was greater than or equal to collection by other sprays, especially for weakly-charged aerosols. Particle charge strength was significantly correlated with collection efficiency. CONCLUSION: Surfactant type affects charged particle spray collection efficiency. Nonionic surfactant sprays performed well in coal dust capture in many of the tested conditions.
Aerosols ; Coal* ; Diffusion ; Dust* ; Particle Size ; Water ; Wind

Research on the deposition of inhaled particles in human pulmonary acinus region is important to the pathogenesis investigation, prevention and treatment of lung diseases. Most of the current research focus on the final deposition fraction of inhaled particles in human acinar region, but little is involved in their dynamic deposition characteristics. In this paper, five multi-alveolar models, G3-G7, were built. The evaluation parameter 1/4 deposition time was introduced to study the particle deposition speed. The deposition characteristics of particles in the diameter ranging 0.1-5 μm were numerically simulated and summarized under the influence of factors such as the generation and structure of model, particle diameter and respiratory mode, shedding some new light on the further research of transport of inhaled particles. The results showed that the generation and structure of model had a significance effect on the deposition of particles. 0.1 μm particles were dominated by Brownian diffusion, which experienced a high deposition fraction, a fast deposition speed and a logarithmic deposition curve, while 5 μm particles were dominated by gravitational sedimentation, with a high deposition fraction, a fast deposition speed and an S-shaped deposition curve. The deposition of 0.3-1 μm particles were influenced greatly by convention and varied with the change of respiratory mode. The research methods and results in this paper can provide theoretical basis and data support for the further exploration of the mechanism, prevention and treatment of lung diseases.
Aerosols ; Computer Simulation ; Humans ; Lung ; Models, Biological ; Particle Size

Objective: To investigate the epidemiological characteristics and the transmission chain of a family clustering of COVID-19 cases caused by severe acute respiratory 2019-nCoV Delta variant in Changping district of Beijing. Methods: Epidemiological investigation was conducted and big data were used to reveal the exposure history of the cases. Close contacts were screened according to the investigation results, and human and environmental samples were collected for nucleic acid tests. Positive samples were analyzed by gene sequencing. Results: On November 1, 2021, a total of 5 COVID-19 cases caused by 2019-nCoV Delta variant were reported in a family detected through active screening. The infection source was a person in the same designated isolation hotel where the first case of the family cluster was isolated from 22 to 27, October. The first case was possibly infected through aerosol particles in the ventilation duct system of the isolation hotel. After the isolation discharge on October 27, and the first case caused secondary infections of four family members while living together from October 27 to November 1, 2021. Conclusion: 2019-nCoV Delta variant is prone to cause family cluster, and close attention needs to be paid to virus transmission through ventilation duct system in isolation hotels.
Aerosols ; COVID-19 ; Epidemics ; Humans ; SARS-CoV-2

BACKGROUND: Medications for asthma can be administered either by inhaled or systemic routes. The major advantages of delivering drugs directly into the lungs via inhalation are that higher concentrations can be delivered more effectively to the airways and that systemic side effects are avoided or minimized. Inhaled medications, or aerosols, are available in a variety of devices that differ in required technique and quantity of drugs delivered to the lung. OBJECTIVE: The purpose of this study was to determine the effects of patient education on correct use of metered dose inhaler in patients with asthma. METHODS: Twenty patients with asthma were instructed three times on proper inhaler usage by a physician at two-week intervals. Practical performance and theoretical knowledge were assessed (ten-item assessment). Scoring was done by one physician using a score of 1-3 for each item. RESULTS: The practical performance and theoretical knowledge scores were higher in patients after being instructed three times compared with those who were instructed once (26.2+/-2.2 vs 18.1+/-3.6, p< 0.01). The scores were higher in patients with higher education level com- pared with those with lower education level after three lessons (27.3+/-1.94 vs 24.3+/-1.80, p< 0.05). The most common errors included inadequate actuation time and breath holding, and insufficient activations. CONCLUSION: These findings suggest that patients with asthma be instructed in inhaler use and that their technique be checked regularly and repeatedly depending on education level.
Aerosols ; Asthma* ; Breath Holding ; Education ; Humans ; Inhalation ; Lung ; Metered Dose Inhalers* ; Nebulizers and Vaporizers ; Patient Education as Topic*

The aim of this review was to assess current knowledge related to the occupational exposure limit (OEL) for fluid aerosols including either mineral or chemical oil that are generated in metalworking operations, and to discuss whether their OEL can be appropriately used to prevent several health risks that may vary among metalworking fluid (MWF) types. The OEL (time-weighted average; 5 mg/m3, short-term exposure limit ; 15 mg/m3) has been applied to MWF aerosols without consideration of different fluid aerosol-size fractions. The OEL, is also based on the assumption that there are no significant differences in risk among fluid types, which may be contentious. Particularly, the health risks from exposure to water-soluble fluids may not have been sufficiently considered. Although adoption of The National Institute for Occupational Safety and Health's recommended exposure limit for MWF aerosol (0.5 mg/m3) would be an effective step towards minimizing and evaluating the upper respiratory irritation that may be caused by neat or diluted MWF, this would fail to address the hazards (e.g., asthma and hypersensitivity pneumonitis) caused by microbial contaminants generated only by the use of water-soluble fluids. The absence of an OEL for the water-soluble fluids used in approximately 80-90 % of all applicants may result in limitations of the protection from health risks caused by exposure to those fluids.
Adoption ; Aerosols ; Asthma ; Hypersensitivity ; Occupational Exposure ; Occupational Health ; Threshold Limit Values