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- Alsved, Malin, et al.
(författare)
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Infectivity of exhaled SARS-CoV-2 aerosols is sufficient to transmit covid-19 within minutes
- 2023
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Ingår i: Scientific Reports. - 2045-2322. ; 13
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Tidskriftsartikel (refereegranskat)abstract
- Exhaled SARS-CoV-2-containing aerosols contributed significantly to the rapid and vast spread of covid-19. However, quantitative experimental data on the infectivity of such aerosols is missing. Here, we quantified emission rates of infectious viruses in exhaled aerosol from individuals within their first days after symptom onset from covid-19. Six aerosol samples from three individuals were culturable, of which five were successfully quantified using TCID50. The source strength of the three individuals was highest during singing, when they exhaled 4, 36, or 127 TCID50/s, respectively. Calculations with an indoor air transmission model showed that if an infected individual with this emission rate entered a room, a susceptible person would inhale an infectious dose within 6 to 37 min in a room with normal ventilation. Thus, our data show that exhaled aerosols from a single person can transmit covid-19 to others within minutes at normal indoor conditions.
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| 5. |
- Hussein, Tareq, et al.
(författare)
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Indoor model simulation for covid-19 transport and exposure
- 2021
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Ingår i: International Journal of Environmental Research and Public Health. - : MDPI AG. - 1661-7827 .- 1660-4601. ; 18:6
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Tidskriftsartikel (refereegranskat)abstract
- Transmission of respiratory viruses is a complex process involving emission, deposition in the airways, and infection. Inhalation is often the most relevant transmission mode in indoor environments. For severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the risk of inhalation transmission is not yet fully understood. Here, we used an indoor aerosol model combined with a regional inhaled deposited dose model to examine the indoor transport of aerosols from an infected person with novel coronavirus disease (COVID-19) to a susceptible person and assess the potential inhaled dose rate of particles. Two scenarios with different ventilation rates were compared, as well as adult female versus male recipients. Assuming a source strength of 10 viruses/s, in a tightly closed room with poor ventilation (0.5 h−1 ), the respiratory tract deposited dose rate was 140–350 and 100–260 inhaled viruses/hour for males and females; respectively. With ventilation at 3 h−1 the dose rate was only 30–90 viruses/hour. Correcting for the half-life of SARS-CoV-2 in air, these numbers are reduced by a factor of 1.2–2.2 for poorly ventilated rooms and 1.1–1.4 for well-ventilated rooms. Combined with future determinations of virus emission rates, the size distribution of aerosols containing the virus, and the infectious dose, these results could play an important role in understanding the full picture of potential inhalation transmission in indoor environments.
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| 6. |
- Hussein, Tareq, et al.
(författare)
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Indoor Particle Concentrations, Size Distributions, and Exposures in Middle Eastern Microenvironments
- 2019
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Ingår i: Atmosphere. - : MDPI AG. - 2073-4433. ; 11:1, s. 1-23
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Tidskriftsartikel (refereegranskat)abstract
- There is limited research on indoor air quality in the Middle East. In this study, concentrations and size distributions of indoor particles were measured in eight Jordanian dwellings during the winter and summer. Supplemental measurements of selected gaseous pollutants were also conducted. Indoor cooking, heating via the combustion of natural gas and kerosene, and tobacco/shisha smoking were associated with significant increases in the concentrations of ultrafine, fine, and coarse particles. Particle number (PN) and particle mass (PM) size distributions varied with the different indoor emission sources and among the eight dwellings. Natural gas cooking and natural gas or kerosene heaters were associated with PN concentrations on the order of 100,000 to 400,000 cm−3 and PM2.5 concentrations often in the range of 10 to 150 µg/m3. Tobacco and shisha (waterpipe or hookah) smoking, the latter of which is common in Jordan, were found to be strong emitters of indoor ultrafine and fine particles in the dwellings. Non-combustion cooking activities emitted comparably less PN and PM2.5. Indoor cooking and combustion processes were also found to increase concentrations of carbon monoxide, nitrogen dioxide, and volatile organic compounds. In general, concentrations of indoor particles were lower during the summer compared to the winter. In the absence of indoor activities, indoor PN and PM2.5 concentrations were generally below 10,000 cm−3 and 30 µg/m3, respectively. Collectively, the results suggest that Jordanian indoor environments can be heavily polluted when compared to the surrounding outdoor atmosphere primarily due to the ubiquity of indoor combustion associated with cooking, heating, and smoking.
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| 7. |
- Hussein, Tareq, et al.
(författare)
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Modeling regional deposited dose of submicron aerosol particles
- 2013
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Ingår i: Science of the Total Environment. - : Elsevier BV. - 1879-1026 .- 0048-9697. ; 458, s. 140-149
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Tidskriftsartikel (refereegranskat)abstract
- We developed a simple model to calculate the regional deposited dose of submicron aerosol particles in the respiratory system. This model incorporates measured outdoor and modeled indoor particle number size distributions, detailed activity patterns of three age groups (teens, adults, and the elderly), semi-empirical estimation of the regional deposition fraction, hygroscopic properties of urban aerosols, and reported breathing minute volumes. We calculated the total and regional deposited dose based on three concentration metrics: particle number (PN), mass (PM), and surface area (PSA). The 24-h total deposited dose of fine particles in adult males was around 40 mu g (57 x 109 particles, 8 x 102 mm(2)) and 41 mu g (40 x 109 particles, 8 x 102 mm(2)) on workdays and weekends, respectively. The total and regional 24-h deposited dose based on any of the metrics was at most 1.5 times higher in males than in females. The deposited dose values in the other age groups were slightly different than in adults. Regardless of the particle size fraction or the deposited dose metric, the pulmonary/alveolar region received the largest fraction of the deposited dose. These values represent the lowest estimate of the deposited dose and they are expected to be higher in real-life conditions after considering indoor sources of aerosol particles and spatial variability of outdoor aerosols. This model can be extended to youngsters (<12 years old) after gaining accurate information about the deposition fraction inside their respiratory system and their breathing pattern. This investigation is foreseen to bridge the gap between exposure and response in epidemiological studies. (C) 2013 Elsevier B.V. All rights reserved.
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| 8. |
- Hussein, Tareq, et al.
(författare)
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Quantification of the inhaled deposited dose during sand and dust storms
- 2023
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Ingår i: Dust and health : challenges and Solutions - challenges and Solutions. - Cham : Springer International Publishing. - 2524-6402 .- 2524-6410. - 9783031212086 - 9783031212093 ; , s. 17-30
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Bokkapitel (refereegranskat)abstract
- Exposure to dust particles during a sand and dust storm (SDS) can be harmful for health. The first step to understand the health effects of such exposure is to quantify the amount of deposited dust particles in the respiratory tracts. In this book chapter, a brief summary is presented about: (1) the outbreak mechanisms dust particles and being airborne, (2) physical and chemical characteristics of dust particles, and (3) toxins and health effects of dust particles. This summary was followed by a simple description about the exposure pathways with a focus on the inhaled deposited dose in the respiratory tract. The regional inhaled deposited dose was quantified by a simple model. The simple dose model was applied to quantify the dose rate for adult males or females being exposed to dust particles (i.e., SDS scenario) and undergoing common activities (resting and exercising).
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| 9. |
- Hussein, Tareq, et al.
(författare)
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Regional inhaled deposited dose of indoor combustion-generated aerosols in jordanian urban homes
- 2020
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Ingår i: Atmosphere. - : MDPI AG. - 2073-4433. ; 11:11
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Tidskriftsartikel (refereegranskat)abstract
- Indoor combustion processes associated with cooking, heating, and smoking are a major source of aerosols in Jordanian dwellings. To evaluate human exposure to combustion-generated aerosols in Jordanian indoor environments, regional inhaled deposited dose rates of indoor aerosols (10 nm to 25 µm) were determined for different scenarios for adult occupants. The inhaled deposited dose rate provides an estimate of the number or mass of inhaled aerosol that deposits in each region of the respiratory system per unit time. In general, sub-micron particle number (PN1) dose rates ranged from 109 to 1012 particles/h, fine particle mass (PM2.5) dose rates ranged from 3 to 216 µg/h, and coarse particle mass (PM10) dose rates ranged from 30 to 1600 µg/h. Dose rates were found to be dependent on the type and intensity of indoor combustion processes documented in the home. Dose rates were highest during cooking activities using a natural gas stove, heating via natural gas and kerosene, and smoking (shisha/tobacco). The relative fraction of the total dose rate received in the head airways, tracheobronchial, and alveolar regions varied among the documented indoor combustion (and non-combustion) activities. The significant fraction of sub-100 nm particles produced during the indoor combustion processes resulted in high particle number dose rates for the alveolar region. Suggested approaches for reducing indoor aerosol dose rates in Jordanian dwellings include a reduction in the prevalence of indoor combustion sources, use of extraction hoods to remove combustion products, and improved ventilation/filtration in residential buildings.
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| 10. |
- Hussein, Tareq, et al.
(författare)
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Regional inhaled deposited dose of urban aerosols in an eastern Mediterranean city
- 2019
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Ingår i: Atmosphere. - : MDPI AG. - 2073-4433. ; 10:9
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Tidskriftsartikel (refereegranskat)abstract
- We calculated the regional deposited dose of inhaled particulate matter based on number/mass concentrations in Amman, Jordan. The dose rate was the highest during exercising but was generally lower for females compared to males. The fine particles dose rate was 1010-1011 particles/h (101-102 μg/h). The PM10 dose rate was 49-439 μg/h for males and 36-381 μg/h for females. While resting, the PM10 deposited in the head airways was 67-77% and 8-12% in the tracheobronchial region. When exercising, the head airways received 37-44% of the PM10, whereas the tracheobronchial region received 31-35%. About 8% (exercise) and 14-16% (rest) of the PM2.5 was received in the head airways, whereas the alveolar received 74-76% (exercise) and 54-62% (rest). Extending the results for common exposure scenarios in the city revealed alarming results for service workers and police officers; they might receive 50 μg/h PM2.5 and 220 μg/h PM10 while doing their duty on main roads adjacent to traffic. This is especially critical for a pregnant police officer. Outdoor athletic activities (e.g., jogging along main roads) are associated with high PM2.5 and PM10 dose rates (100 μg/h and ~425 μg/h, respectively).
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