Measurements of the Size Distribution of Aerosols Produced by Ultrasonic Humidification

Rodes, Charles; Smith, Tom E. C.; Crouse, R.S.; Ramachandran, Gurumurthy

doi:10.1080/02786829008959440

Cited by 65 publications

(50 citation statements)

References 7 publications

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“…All three nebulizers exhibit similar distributions that are not monotonic and have multimodal peaks. Bimodal peaks were also observed in mass size distribution measurements of Rodes et al (1990) for wet and dry salt particles generated by an ultrasonic room humidifier. This phenomenon may be attributed to the kinematic coagulation of the particles in the nebulizers after bouncing off the walls.…”

Section: Resultsmentioning

confidence: 75%

Generation of Submicron Mass/Volume-Monodisperse Aerosols with a Nebulizer-Impactor-Electrostatic Classifier System

Asgharian

Fang

Cohen

1992

Aerosol Science and Technology

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A study was undertaken to investigate the mass size dispersion of particles classified according to their electrical mobilities. This is of primary concern in experiments that measure a concentration dependent property of the classified particles. Initially, the mass size distribution of particles produced by the 3-jet Collison, 6-jet Collison, and Misty-Ox nebulizers was measured. A 0-2 stage impactor was,placed after the nebulizers and the size mass distribution was measured again. The polydisperse particle stream was then used to generate "size classified" aerosol and the mass size distribution of the equal mobility particles was calculated and measured. It was found that without an impactor in line, the aerosol stream contained a significant mass fraction of multiply charged particles. When an impactor was inserted directly after the nebulizers, the multiply charged particles were effectively removed and the particles were nearly monodisperse.

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Section: Resultsmentioning

confidence: 75%

Generation of Submicron Mass/Volume-Monodisperse Aerosols with a Nebulizer-Impactor-Electrostatic Classifier System

Asgharian

Fang

Cohen

1992

Aerosol Science and Technology

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“…1,10,12,13,31 For that reason, it is important to consider the mineral composition of water when evaluating particle characteristics. By definition, high hardness waters contain elevated concentrations of calcium and magnesium.…”

Section: Tap Waters Contain Varying Concentrations Of Dissolved Minermentioning

confidence: 99%

Size and mineral composition of airborne particles generated by an ultrasonic humidifier

et al. 2017

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This study describes the size distribution and concentration of particles expelled by a portable, 3-L ultrasonic humidifier. The ultrasonic humidifier was filled with waters of varying mineral content and hardness. Aerosol size distributions were measured during 8 hours of humidifier operation in a typical bedroom. Humidifiers produced approximately 1.22 × 10 10 -2.50 × 10 10 airborne particles per milliliter of water consumed, resulting in airborne particle concentrations of 3.01-5.91 × 10 4 #/cm 3 , with modes ranging between 109 and 322 nm in diameter. The emission rate of particles varied by water type from 1.02 × 10 9 to 2.27 × 10 9 #/s. Lower mineral waters produced fewer, smaller particles when compared to higher mineral waters. Chemical analyses of particles collected with a cascade impactor indicated that the minerals in emitted particles had the same relative mineral concentrations as the fill water. Our results demonstrate that ultrasonic humidifiers should be considered a source of inhalation exposure to minerals dissolved in water, and that the magnitude of exposure to inhalable particles will vary with water quality. K E Y W O R D Sair quality, air-water interface, humidifier, inhalation exposure, PM2.5, water quality While humidifiers offer increased comfort and improved wellbeing by raising humidity indoors, they may also introduce contaminants to indoor air. This is less of a concern with evaporative humidifiers, which release only water and highly volatile compounds into air, but is a possibility with ultrasonic humidifiers, as they create tiny droplets consisting of water and its impurities. Once the water evaporates, the impurities can remain suspended as airborne particles. | INTRODUCTIONOne of the primary concerns for household humidifiers is their ability to aerosolize pathogenic microbes. 7,8 There is limited information about a humidifier's ability to aerosolize specific minerals, though it is acknowledged that use of waters containing minerals may result in expulsion of "white dust." 1,9,10 This "white dust" was associated with respiratory distress in children if inhaled and was found to be deposited in the lungs of mice exposed to humidifier effluent. 11,12 Ultrasonic humidifiers efficiently aerosolize 85%-90% of dissolved minerals present in the water used to fill the humidifier. 10,13Indoor air quality is not frequently monitored within a household, although individuals spend ~90% of their time indoors 14 and tighter buildings are leading to higher contaminant concentrations and, therefore, increased exposures to inhalable contaminants. 15 Common sources of indoor particles include cooking (eg, frying, grilling, and the use of appliances such as stoves, ovens, microwaves), vacuuming, smoking, using photocopiers and color printers, and burning candles or incense, resulting in increases in particle concentrations 1.5-27 times | 81above background concentrations. [16][17][18] The increased exposure time to indoor air, combined with an ultrasonic humidifier's ability to efficient...

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“…In its powdered form, PHMG-P has a particle diameter of 20-40 μm. However, aerosol particles dry rapidly once sprayed from an ultrasonic humidifier, shrinking to nanometer-sized particles that can easily penetrate the lungs (Rodes et al, 1990). One study measured the aerosol particles sprayed from disinfectant-added humidifiers, and found diameters in the range of 30-80 nm (KCDC, 2011), suggesting that PHMG-P in aerosol sprayed from ultrasonic humidifiers could reach deep into the lungs and accumulate there.…”

Section: Physiochemical Properties Of Phmg-pmentioning

confidence: 99%

Adverse health effects of humidifier disinfectants in Korea: lung toxicity of polyhexamethylene guanidine phosphate

et al. 2016

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-Exposure to humidifier disinfectants was identified in 2011 as the potential cause of an outbreak of lung disease in Korea. It is estimated that over 8 million people have been exposed to humidifier disinfectants-chemicals added to the water used in humidifiers to prevent the growth of microorganisms-since their commercial introduction. The primary component of humidifier disinfectant products involved was polyhexamethylene guanidine phosphate (PHMG-P), a guanidine-based antimicrobial agent. Lesions observed in the lungs of patients were similar to those observed in laboratory animals exposed to PHMG-P. In this review, we outline the physicochemical and toxicological properties of PHMG-P, and introduce a putative mechanism for its lung toxicity based in large part on research findings to date.

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Measurements of the Size Distribution of Aerosols Produced by Ultrasonic Humidification

Cited by 65 publications

References 7 publications

Generation of Submicron Mass/Volume-Monodisperse Aerosols with a Nebulizer-Impactor-Electrostatic Classifier System

Generation of Submicron Mass/Volume-Monodisperse Aerosols with a Nebulizer-Impactor-Electrostatic Classifier System

Size and mineral composition of airborne particles generated by an ultrasonic humidifier

Adverse health effects of humidifier disinfectants in Korea: lung toxicity of polyhexamethylene guanidine phosphate

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