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Andrea M Dietrich - One of the best experts on this subject based on the ideXlab platform.
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an overlooked route of inhalation exposure to tap water constituents for children and adults aerosolized aqueous minerals from ultrasonic Humidifiers
Water research X, 2020Co-Authors: Wenchuo Yao, Daniel L Gallagher, Andrea M DietrichAbstract:Abstract Fine particulates and aerosols emitted by commonly used, room-sized ultrasonic Humidifiers may pose adverse health effects to children and adults. The literature documents adverse effects for children exposed to minerals emitted from Humidifiers. This study performs novel and comprehensive characterization of bivariate particle size and element concentrations of emitted airborne aerosols and particles from ultrasonic Humidifiers filled with tap water, including size distribution from 0.014 to 10 μm by scanning mobility particle sizer and AeroTrak; corresponding metal and elemental concentrations as a function of particle size by inductively coupled plasma mass spectrometer; and calculations of deposition fraction in human lungs for age-specific groups using the multi-path particle dosimetry model (MPPD). Deposition fraction is the ratio of mass deposited to total mass inhaled. When filled with tap water, water evaporated from emitted aerosols to form submicron particles that became essentially “dried tap water” with median size 146 nm and mean concentration of 211 μg-total elements/m3-air including 35 μg-calcium/m3-air in a room of 33.5 m3 and air exchange rate at ∼0.8 hr−1. Approximately 90% of emitted particles deposited in human lungs were 1 μm consisted of lower elemental concentrations and more water due to low evaporation. Deposition fraction in pulmonary region was ∼2-fold higher, and deposited particulate mass was 3.5-fold higher for children than adults, indicating greater inhalation exposure to children compared to adults. Modeled data of total particles mass per body weight (BW) that will deposit in adult and child lungs after 8-h humidifier exposure were respectively 2.8 μg/kg-BW and 9.8 μg/kg-BW, where calcium contributes 0.4 μg/kg-BW and 1.6 μg/kg-BW. This comprehensive study of bivariate inorganic chemical composition as a function of particle size expanded, quantified, and modeled exposure for children and adults to aerosolized calcium and other inorganic constituents in water.
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human exposure to particles at the air water interface influence of water quality on indoor air quality from use of ultrasonic Humidifiers
Environment International, 2020Co-Authors: Wenchuo Yao, Daniel L Gallagher, Rachael Dal Porto, Andrea M DietrichAbstract:Abstract Ultrasonic Humidifiers provide indoor relief to symptoms caused by dry air and produce aerosols containing both water and minerals that are present in the water that fills the humidifier. This study investigated the spatial distributions, concentrations, and metal and mineral composition of aerosols emitted when an ultrasonic humidifier was filled with deionized water (DI), low mineral tap water (LL), high total dissolved solids (TDS)/high hardness water (HH), and high TDS/low hardness water (HL). Aerosol/particle sizes and counts were obtained at six horizontal distances in both the plume and near floor for each water quality. Results are that water quality significantly affects particle size distributions which become uniform after 0.9 m from the humidifier outlet, and are independent of vertical distance from the humidifier. The mean count median diameters were 64 nm for DI, 129 nm for LL, 234 nm for HH, and 260 nm for HL; the particle counts and total mineral solids concentrations were 2,194 #/cm3 (16 µg/m3) for DI, 21,070 #/cm3 (113 µg/m3) for LL, 38,353 #/cm3 (438 µg/m3) for HH, and 43,880 #/cm3 (521 µg/m3) for HL. The µg/m3 values for LL, HH, and HL exceeded PM2.5 ambient air standards. Model predictions are that the deposition mass in the human respiratory system from inhaling particles emitted from HH and HL water exceed 135 µg for a 1 to 3-month old child and 600 µg for an adult over an 8-hr period. Mineral water quality significantly affects the distribution and concentration of emitted and inhaled indoor air particles. Consumers may unknowingly be degrading their indoor air quality when using tap water of acceptable drinking water quality as humidifier fill water.
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emission of iron and aluminum oxide particles from ultrasonic Humidifiers and potential for inhalation
Water Research, 2019Co-Authors: Wenchuo Yao, Daniel L Gallagher, Linsey C Marr, Andrea M DietrichAbstract:Abstract Ultrasonic humidifier use is a potential source of human exposure to inhalable particulates. This research evaluated the behavior of insoluble iron oxide and aluminum oxide particles in water used to fill room-sized ultrasonic Humidifiers. Solutions of 10 mg/L Fe, as iron oxide particles, or 5 mg/L Al, as aluminum oxide suspension, were added into tap water used to fill ultrasonic Humidifiers. The Humidifiers were operated for 14 h; samples were obtained over time and monitored for soluble and particulate Fe and Al, as well as particle sizes in the humidifier reservoir and emitted in aerosols. Denser, settleable particles of approximately 1.5 μm diameter of iron or aluminum oxides accumulated at the bottom of the humidifier reservoir. Smaller, suspended metal oxide particles of 0.22–0.57 μm diameter were emitted as aerosols from the humidifier. Soluble anions and cations in tap water were also present in the aerosols emitted from Humidifiers. The results indicate that a typical 1.6 MHz ultrasonic humidifier can emit 0.22–0.57 μm particles and dissolved minerals from fill water into breathable air.
Wenchuo Yao - One of the best experts on this subject based on the ideXlab platform.
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an overlooked route of inhalation exposure to tap water constituents for children and adults aerosolized aqueous minerals from ultrasonic Humidifiers
Water research X, 2020Co-Authors: Wenchuo Yao, Daniel L Gallagher, Andrea M DietrichAbstract:Abstract Fine particulates and aerosols emitted by commonly used, room-sized ultrasonic Humidifiers may pose adverse health effects to children and adults. The literature documents adverse effects for children exposed to minerals emitted from Humidifiers. This study performs novel and comprehensive characterization of bivariate particle size and element concentrations of emitted airborne aerosols and particles from ultrasonic Humidifiers filled with tap water, including size distribution from 0.014 to 10 μm by scanning mobility particle sizer and AeroTrak; corresponding metal and elemental concentrations as a function of particle size by inductively coupled plasma mass spectrometer; and calculations of deposition fraction in human lungs for age-specific groups using the multi-path particle dosimetry model (MPPD). Deposition fraction is the ratio of mass deposited to total mass inhaled. When filled with tap water, water evaporated from emitted aerosols to form submicron particles that became essentially “dried tap water” with median size 146 nm and mean concentration of 211 μg-total elements/m3-air including 35 μg-calcium/m3-air in a room of 33.5 m3 and air exchange rate at ∼0.8 hr−1. Approximately 90% of emitted particles deposited in human lungs were 1 μm consisted of lower elemental concentrations and more water due to low evaporation. Deposition fraction in pulmonary region was ∼2-fold higher, and deposited particulate mass was 3.5-fold higher for children than adults, indicating greater inhalation exposure to children compared to adults. Modeled data of total particles mass per body weight (BW) that will deposit in adult and child lungs after 8-h humidifier exposure were respectively 2.8 μg/kg-BW and 9.8 μg/kg-BW, where calcium contributes 0.4 μg/kg-BW and 1.6 μg/kg-BW. This comprehensive study of bivariate inorganic chemical composition as a function of particle size expanded, quantified, and modeled exposure for children and adults to aerosolized calcium and other inorganic constituents in water.
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human exposure to particles at the air water interface influence of water quality on indoor air quality from use of ultrasonic Humidifiers
Environment International, 2020Co-Authors: Wenchuo Yao, Daniel L Gallagher, Rachael Dal Porto, Andrea M DietrichAbstract:Abstract Ultrasonic Humidifiers provide indoor relief to symptoms caused by dry air and produce aerosols containing both water and minerals that are present in the water that fills the humidifier. This study investigated the spatial distributions, concentrations, and metal and mineral composition of aerosols emitted when an ultrasonic humidifier was filled with deionized water (DI), low mineral tap water (LL), high total dissolved solids (TDS)/high hardness water (HH), and high TDS/low hardness water (HL). Aerosol/particle sizes and counts were obtained at six horizontal distances in both the plume and near floor for each water quality. Results are that water quality significantly affects particle size distributions which become uniform after 0.9 m from the humidifier outlet, and are independent of vertical distance from the humidifier. The mean count median diameters were 64 nm for DI, 129 nm for LL, 234 nm for HH, and 260 nm for HL; the particle counts and total mineral solids concentrations were 2,194 #/cm3 (16 µg/m3) for DI, 21,070 #/cm3 (113 µg/m3) for LL, 38,353 #/cm3 (438 µg/m3) for HH, and 43,880 #/cm3 (521 µg/m3) for HL. The µg/m3 values for LL, HH, and HL exceeded PM2.5 ambient air standards. Model predictions are that the deposition mass in the human respiratory system from inhaling particles emitted from HH and HL water exceed 135 µg for a 1 to 3-month old child and 600 µg for an adult over an 8-hr period. Mineral water quality significantly affects the distribution and concentration of emitted and inhaled indoor air particles. Consumers may unknowingly be degrading their indoor air quality when using tap water of acceptable drinking water quality as humidifier fill water.
-
emission of iron and aluminum oxide particles from ultrasonic Humidifiers and potential for inhalation
Water Research, 2019Co-Authors: Wenchuo Yao, Daniel L Gallagher, Linsey C Marr, Andrea M DietrichAbstract:Abstract Ultrasonic humidifier use is a potential source of human exposure to inhalable particulates. This research evaluated the behavior of insoluble iron oxide and aluminum oxide particles in water used to fill room-sized ultrasonic Humidifiers. Solutions of 10 mg/L Fe, as iron oxide particles, or 5 mg/L Al, as aluminum oxide suspension, were added into tap water used to fill ultrasonic Humidifiers. The Humidifiers were operated for 14 h; samples were obtained over time and monitored for soluble and particulate Fe and Al, as well as particle sizes in the humidifier reservoir and emitted in aerosols. Denser, settleable particles of approximately 1.5 μm diameter of iron or aluminum oxides accumulated at the bottom of the humidifier reservoir. Smaller, suspended metal oxide particles of 0.22–0.57 μm diameter were emitted as aerosols from the humidifier. Soluble anions and cations in tap water were also present in the aerosols emitted from Humidifiers. The results indicate that a typical 1.6 MHz ultrasonic humidifier can emit 0.22–0.57 μm particles and dissolved minerals from fill water into breathable air.
Daniel L Gallagher - One of the best experts on this subject based on the ideXlab platform.
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an overlooked route of inhalation exposure to tap water constituents for children and adults aerosolized aqueous minerals from ultrasonic Humidifiers
Water research X, 2020Co-Authors: Wenchuo Yao, Daniel L Gallagher, Andrea M DietrichAbstract:Abstract Fine particulates and aerosols emitted by commonly used, room-sized ultrasonic Humidifiers may pose adverse health effects to children and adults. The literature documents adverse effects for children exposed to minerals emitted from Humidifiers. This study performs novel and comprehensive characterization of bivariate particle size and element concentrations of emitted airborne aerosols and particles from ultrasonic Humidifiers filled with tap water, including size distribution from 0.014 to 10 μm by scanning mobility particle sizer and AeroTrak; corresponding metal and elemental concentrations as a function of particle size by inductively coupled plasma mass spectrometer; and calculations of deposition fraction in human lungs for age-specific groups using the multi-path particle dosimetry model (MPPD). Deposition fraction is the ratio of mass deposited to total mass inhaled. When filled with tap water, water evaporated from emitted aerosols to form submicron particles that became essentially “dried tap water” with median size 146 nm and mean concentration of 211 μg-total elements/m3-air including 35 μg-calcium/m3-air in a room of 33.5 m3 and air exchange rate at ∼0.8 hr−1. Approximately 90% of emitted particles deposited in human lungs were 1 μm consisted of lower elemental concentrations and more water due to low evaporation. Deposition fraction in pulmonary region was ∼2-fold higher, and deposited particulate mass was 3.5-fold higher for children than adults, indicating greater inhalation exposure to children compared to adults. Modeled data of total particles mass per body weight (BW) that will deposit in adult and child lungs after 8-h humidifier exposure were respectively 2.8 μg/kg-BW and 9.8 μg/kg-BW, where calcium contributes 0.4 μg/kg-BW and 1.6 μg/kg-BW. This comprehensive study of bivariate inorganic chemical composition as a function of particle size expanded, quantified, and modeled exposure for children and adults to aerosolized calcium and other inorganic constituents in water.
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human exposure to particles at the air water interface influence of water quality on indoor air quality from use of ultrasonic Humidifiers
Environment International, 2020Co-Authors: Wenchuo Yao, Daniel L Gallagher, Rachael Dal Porto, Andrea M DietrichAbstract:Abstract Ultrasonic Humidifiers provide indoor relief to symptoms caused by dry air and produce aerosols containing both water and minerals that are present in the water that fills the humidifier. This study investigated the spatial distributions, concentrations, and metal and mineral composition of aerosols emitted when an ultrasonic humidifier was filled with deionized water (DI), low mineral tap water (LL), high total dissolved solids (TDS)/high hardness water (HH), and high TDS/low hardness water (HL). Aerosol/particle sizes and counts were obtained at six horizontal distances in both the plume and near floor for each water quality. Results are that water quality significantly affects particle size distributions which become uniform after 0.9 m from the humidifier outlet, and are independent of vertical distance from the humidifier. The mean count median diameters were 64 nm for DI, 129 nm for LL, 234 nm for HH, and 260 nm for HL; the particle counts and total mineral solids concentrations were 2,194 #/cm3 (16 µg/m3) for DI, 21,070 #/cm3 (113 µg/m3) for LL, 38,353 #/cm3 (438 µg/m3) for HH, and 43,880 #/cm3 (521 µg/m3) for HL. The µg/m3 values for LL, HH, and HL exceeded PM2.5 ambient air standards. Model predictions are that the deposition mass in the human respiratory system from inhaling particles emitted from HH and HL water exceed 135 µg for a 1 to 3-month old child and 600 µg for an adult over an 8-hr period. Mineral water quality significantly affects the distribution and concentration of emitted and inhaled indoor air particles. Consumers may unknowingly be degrading their indoor air quality when using tap water of acceptable drinking water quality as humidifier fill water.
-
emission of iron and aluminum oxide particles from ultrasonic Humidifiers and potential for inhalation
Water Research, 2019Co-Authors: Wenchuo Yao, Daniel L Gallagher, Linsey C Marr, Andrea M DietrichAbstract:Abstract Ultrasonic humidifier use is a potential source of human exposure to inhalable particulates. This research evaluated the behavior of insoluble iron oxide and aluminum oxide particles in water used to fill room-sized ultrasonic Humidifiers. Solutions of 10 mg/L Fe, as iron oxide particles, or 5 mg/L Al, as aluminum oxide suspension, were added into tap water used to fill ultrasonic Humidifiers. The Humidifiers were operated for 14 h; samples were obtained over time and monitored for soluble and particulate Fe and Al, as well as particle sizes in the humidifier reservoir and emitted in aerosols. Denser, settleable particles of approximately 1.5 μm diameter of iron or aluminum oxides accumulated at the bottom of the humidifier reservoir. Smaller, suspended metal oxide particles of 0.22–0.57 μm diameter were emitted as aerosols from the humidifier. Soluble anions and cations in tap water were also present in the aerosols emitted from Humidifiers. The results indicate that a typical 1.6 MHz ultrasonic humidifier can emit 0.22–0.57 μm particles and dissolved minerals from fill water into breathable air.
Masanobu Manabe - One of the best experts on this subject based on the ideXlab platform.
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a comparison of the rate of bacterial contamination for prefilled disposable and reusable oxygen Humidifiers
Journal of Critical Care, 2005Co-Authors: Koichi Yamashita, Tomoki Nishiyama, Takeshi Yokoyama, Hidehiro Abe, Masanobu ManabeAbstract:Background: Prefilled disposable oxygen Humidifiers are considered to prevent nosocomial pneumonia in hospital wards. However, their usefulness in intensive care units (ICUs) has not yet been established. In this study, we evaluated and compared contamination in prefilled disposable oxygen Humidifiers and that in reusable oxygen Humidifiers. Methods: Six oxygen outlets in the ICU were used. Prefilled disposable oxygen Humidifiers and reusable oxygen Humidifiers were attached to each wall-mounted oxygen outlet using a 2-way connector. Nonsterile nasal cannulae and tubes were connected to the Humidifiers through which 5 L/min of oxygen was delivered continuously. Water samples (5 mL) from each humidifier were collected on the first day and every 7 days thereafter for a period of 56 days. Each water sample was incubated aerobically at 358C for 48 hours and observed daily for bacterial growth. Results: Bacterial growth was observed only once in one sample from each humidifier type. Grampositive cocci, 40 colony-forming units in the disposable oxygen humidifier and 10 colony-forming units in the reusable oxygen humidifier, were detected. Dust was observed from the 35th day onward only in the reusable oxygen humidifier. Conclusion: In the ICU, bacterial contamination does not occur in oxygen Humidifiers even after 56 days of continuous use. However, dust does accumulate in the reusable oxygen humidifier after 35 days of continuous use.
Koichi Yamashita - One of the best experts on this subject based on the ideXlab platform.
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a comparison of the rate of bacterial contamination for prefilled disposable and reusable oxygen Humidifiers
Journal of Critical Care, 2005Co-Authors: Koichi Yamashita, Tomoki Nishiyama, Takeshi Yokoyama, Hidehiro Abe, Masanobu ManabeAbstract:Background: Prefilled disposable oxygen Humidifiers are considered to prevent nosocomial pneumonia in hospital wards. However, their usefulness in intensive care units (ICUs) has not yet been established. In this study, we evaluated and compared contamination in prefilled disposable oxygen Humidifiers and that in reusable oxygen Humidifiers. Methods: Six oxygen outlets in the ICU were used. Prefilled disposable oxygen Humidifiers and reusable oxygen Humidifiers were attached to each wall-mounted oxygen outlet using a 2-way connector. Nonsterile nasal cannulae and tubes were connected to the Humidifiers through which 5 L/min of oxygen was delivered continuously. Water samples (5 mL) from each humidifier were collected on the first day and every 7 days thereafter for a period of 56 days. Each water sample was incubated aerobically at 358C for 48 hours and observed daily for bacterial growth. Results: Bacterial growth was observed only once in one sample from each humidifier type. Grampositive cocci, 40 colony-forming units in the disposable oxygen humidifier and 10 colony-forming units in the reusable oxygen humidifier, were detected. Dust was observed from the 35th day onward only in the reusable oxygen humidifier. Conclusion: In the ICU, bacterial contamination does not occur in oxygen Humidifiers even after 56 days of continuous use. However, dust does accumulate in the reusable oxygen humidifier after 35 days of continuous use.