scholarly journals Efficacy of Ventilation, HEPA Air Cleaners, Universal Masking, and Physical Distancing for Reducing Exposure to Simulated Exhaled Aerosols in a Meeting Room

Viruses ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 2536
Author(s):  
Jayme P. Coyle ◽  
Raymond C. Derk ◽  
William G. Lindsley ◽  
Francoise M. Blachere ◽  
Theresa Boots ◽  
...  
Keyword(s):  
Indoor Environment ◽  
Aerosol Particles ◽  
Personal Exposure ◽  
Mitigation Strategies ◽  
Face To Face ◽  
Meeting Room ◽  
Aerosol Exposure ◽  
Fine Aerosol ◽  
Unit Increase ◽  
Air Cleaners

There is strong evidence associating the indoor environment with transmission of SARS-CoV-2, the virus that causes COVID-19. SARS-CoV-2 can spread by exposure to droplets and very fine aerosol particles from respiratory fluids that are released by infected persons. Layered mitigation strategies, including but not limited to maintaining physical distancing, adequate ventilation, universal masking, avoiding overcrowding, and vaccination, have shown to be effective in reducing the spread of SARS-CoV-2 within the indoor environment. Here, we examine the effect of mitigation strategies on reducing the risk of exposure to simulated respiratory aerosol particles within a classroom-style meeting room. To quantify exposure of uninfected individuals (Recipients), surrogate respiratory aerosol particles were generated by a breathing simulator with a headform (Source) that mimicked breath exhalations. Recipients, represented by three breathing simulators with manikin headforms, were placed in a meeting room and affixed with optical particle counters to measure 0.3–3 µm aerosol particles. Universal masking of all breathing simulators with a 3-ply cotton mask reduced aerosol exposure by 50% or more compared to scenarios with simulators unmasked. While evaluating the effect of Source placement, Recipients had the highest exposure at 0.9 m in a face-to-face orientation. Ventilation reduced exposure by approximately 5% per unit increase in air change per hour (ACH), irrespective of whether increases in ACH were by the HVAC system or portable HEPA air cleaners. The results demonstrate that mitigation strategies, such as universal masking and increasing ventilation, reduce personal exposure to respiratory aerosols within a meeting room. While universal masking remains a key component of a layered mitigation strategy of exposure reduction, increasing ventilation via system HVAC or portable HEPA air cleaners further reduces exposure.

scholarly journals Reduction of exposure to simulated respiratory aerosols using ventilation, physical distancing, and universal masking

2021 ◽  
Author(s):  
Jayme P. Coyle ◽  
Raymond C Derk ◽  
William G Lindsley ◽  
Theresa Boots ◽  
Francoise M. Blachere ◽  
...  
Keyword(s):  
Indoor Environment ◽  
Respiratory Activity ◽  
Aerosol Particles ◽  
Inhalation Exposure ◽  
Mitigation Strategies ◽  
Engineering Controls ◽  
Particle Exposure ◽  
Adequate Ventilation ◽  
Respiratory Droplets ◽  
Indoor Spaces

To limit community spread of SARS-CoV-2, CDC recommends universal masking indoors, maintaining 1.8 m of physical distancing, adequate ventilation, and avoiding crowded indoor spaces. Several studies have examined the independent influence of each control strategy in mitigating transmission in isolation, yet controls are often implemented concomitantly within an indoor environment. To address the influence of physical distancing, universal masking, and ventilation on very fine respiratory droplets and aerosol particle exposure, a simulator that coughed and exhaled aerosols (the source) and a second breathing simulator (the recipient) were placed in an exposure chamber. When controlling for the other two mitigation strategies, universal masking with 3-ply cotton masks reduced exposure to 0.3-3 μm coughed and exhaled aerosol particles by > 77% compared to unmasked tests, whereas physical distancing (0.9 or 1.8 m) significantly changed exposure to cough but not exhaled aerosols. The effectiveness of ventilation depended upon the respiratory activity, i.e., coughing or breathing, as well as the duration of exposure time. Our results demonstrate that a combination of administrative and engineering controls can reduce personal inhalation exposure to potentially infectious very fine respiratory droplets and aerosol particles within an indoor environment.

MEMS Based Gravimetric Sensor for the Detection of Ultra-Fine Aerosol Particles

2020 ◽  
Author(s):  
Malar Chellasivalingam ◽  
Laxmeesha Somappa ◽  
Adam M. Boies ◽  
Maryam Shojaei Baghini ◽  
Ashwin A. Seshia
Keyword(s):  
Aerosol Particles ◽  
Fine Aerosol

Nucleation-assisted process for the removal of fine aerosol particles

1993 ◽  
Vol 32 (7) ◽  
pp. 1509-1519 ◽  
Author(s):  
Chin Cheng Chen ◽  
Han Kuan Shu ◽  
Yeun Kwei Yang
Keyword(s):  
Aerosol Particles ◽  
Fine Aerosol

Learning landslide hazard in a virtual environment at University level combining real case study, collaborative work and innovative tools

2021 ◽  
Author(s):  
Marta Guinau ◽  
Gloria Furdada
Keyword(s):  
Digital Media ◽  
Collaborative Work ◽  
Relevant Information ◽  
Landslide Hazard ◽  
Mitigation Strategies ◽  
Significant Information ◽  
Digital Platforms ◽  
Face To Face ◽  
Triggering Factors ◽  
Different Types

<p>The pandemic situation we are experiencing has forced us to transform face-to-face teaching into virtual teaching. Digital platforms hinder the interaction, discussion and feedback that naturally occur in a face-to-face class, but at the same time, they provide an opportunity to put the focus on the student’s learning rather than on content delivering. Learning include both, inductive and deductive processes; induction can be effectively acquired by using case studies; then, deduction can be achieved through comparison, analysis, generalisation and synthesis.  Digital platforms appear as an optimal resource to facilitate the individual and collaborative tasks and learning processes. In this work we present our experience on the landslide hazard subject (Master’s level) focussed on the student’s learning through the use of digital media.</p><p>Internet information of undeniable quality that can be easily accessed is basic: The Landslide Blog by Dave Petley (https://blogs.agu.org/landslideblog/) in Blogosphere hosted by AGU (American Geophysical Union) provides valuable and updated information on landslide events occurring worldwide. The learning activities are structured around several cases selected by the lecturer from the blog to ensure the analysis of the most frequent landslide types. All activities are developed in 8 steps: 1) The teacher presents the learning action (objective, tasks, and assessment guide) using a Genially platform interactive image; 2) Each student selects one of the proposed cases and compile relevant information about it; 3) Each student analyses the landslide characteristics, identifies the landslide type  and classifies it according to Hungr et al., 2014 (available through the educational virtual platform), and recognises the control and triggering factors (one virtual session is programmed and a forum tool is provided to the students to discuss and to solve doubts); 4) Each student selects and organizes the significant information about each case by building an interactive image in Genially; 5) Each student presents each case using his/her interactive image in a virtual session, which is recorded and uploaded to the educational platform; 6) Students peer evaluate the content and design of the interactive images and oral presentations based on the provided assessment guide; 7) During a predetermined time, students collaboratively compile all the information in a Google sheet table to synthesize the geomorphological characteristics, materials involved, mobilization mechanisms and control and triggering factors of the different types of landslides; 8) the synthetic table is discussed and  completed during a virtual session.</p><p>All the knowledge and skills acquired by students with these activities are put into practice in a two-day field trip where students have to identify, characterize and classify different types of landslides as well as their control and triggering factors. The risk situation and the mitigation strategies are discussed in each case and compared to the ones studied through virtual learning. Furthermore, students get used and learn how to clearly present information through virtual tools, as Genially, useful for dissemination purposes.</p><p>Hungr et al. 2014. The Varnes classification of landslide types, an update. Landslides 11(2). DOI: 10.1007/s10346-013-0436-y</p>

scholarly journals Nontuberculous Mycobacterial Disease and Molybdenum in Colorado Watersheds

2020 ◽  
Vol 17 (11) ◽  
pp. 3854
Author(s):  
Ettie M. Lipner ◽  
Joshua French ◽  
Carleton R. Bern ◽  
Katherine Walton-Day ◽  
David Knox ◽  
...  
Keyword(s):  
Water Quality ◽  
Linear Models ◽  
Disease Risk ◽  
Mitigation Strategies ◽  
Quality Data ◽  
Source Water ◽  
Water Quality Data ◽  
Unit Increase ◽  
Discrete Responses ◽  
Environmental Bacteria

Nontuberculous mycobacteria (NTM) are environmental bacteria that may cause chronic lung disease. Environmental factors that favor NTM growth likely increase the risk of NTM exposure within specific environments. We aimed to identify water-quality constituents (Al, As, Cd, Ca, Cu, Fe, Pb, Mg, Mn, Mo, Ni, K, Se, Na, Zn, and pH) associated with NTM disease across Colorado watersheds. We conducted a geospatial, ecological study, associating data from patients with NTM disease treated at National Jewish Health and water-quality data from the Water Quality Portal. Water-quality constituents associated with disease risk were identified using generalized linear models with Poisson-distributed discrete responses. We observed a highly robust association between molybdenum (Mo) in the source water and disease risk. For every 1- unit increase in the log concentration of molybdenum in the source water, disease risk increased by 17.0%. We also observed a statistically significant association between calcium (Ca) in the source water and disease risk. The risk of NTM varied by watershed and was associated with watershed-specific water-quality constituents. These findings may inform mitigation strategies to decrease the overall risk of exposure.

scholarly journals Distribution of Atmospheric Aerosol over the South China Sea

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Shih-Jen Huang ◽  
Chen-Chih Lin
Keyword(s):  
South China Sea ◽  
South China ◽  
Aerosol Particles ◽  
Correlation Coefficients ◽  
The South China Sea ◽  
The South ◽  
China Sea ◽  
Fine Aerosol ◽  
Coarse Aerosol

The satellite-derived aerosol optical depth (AOD) data is used to investigate the distribution of aerosol over the South China Sea (SCS). High correlation coefficients are found between in situ AERONET data and satellite AOD measurements around the SCS with the highest coefficient of 0.9 on the Dongsha Island (i.e., Pratas Island). The empirical orthogonal function (EOF) analysis of AOD over the SCS shows that high AOD is always found around offshore areas of China, Indochina, Sumatra, and Borneo. Besides, spring is the major season of occurring coarse aerosol particles (AOT_C) but fine aerosol particles (AOT_F) occur yearly. The biomass burning is found in Indochina during March and April, and so it is in Sumatra and Borneo from August to October. The results also show that the AOT_F are higher during El Niño events, but higher AOT_C are found in La Niña years.

On the filtration of fine aerosol particles by a dual-wire fibre filter

1997 ◽  
Vol 39 (2) ◽  
pp. 145-153 ◽  
Author(s):  
M. Chiruţa ◽  
M. Slaninǎ ◽  
M. Duca
Keyword(s):  
Aerosol Particles ◽  
Fine Aerosol

scholarly journals Electrostatic Precipitators as an Indoor Air Cleaner—A Literature Review

2020 ◽  
Vol 12 (21) ◽  
pp. 8774
Author(s):  
Alireza Afshari ◽  
Lars Ekberg ◽  
Luboš Forejt ◽  
Jinhan Mo ◽  
Siamak Rahimi ◽  
...  
Keyword(s):  
Indoor Air ◽  
Indoor Environment ◽  
Indoor Environmental Quality ◽  
Air Filtration ◽  
Pressure Drops ◽  
Air Cleaning ◽  
Air Cleaner ◽  
Air Cleaners ◽  
Electrostatic Precipitators ◽  
Cleaning Technology

Many people spend most of their time in an indoor environment. A positive relationship exists between indoor environmental quality and the health, wellbeing, and productivity of occupants in buildings. The indoor environment is affected by pollutants, such as gases and particles. Pollutants can be removed from the indoor environment in various ways. Air-cleaning devices are commonly marketed as benefiting the removal of air pollutants and, consequently, improving indoor air quality. Depending on the type of cleaning technology, air cleaners may generate undesired and toxic byproducts. Different air filtration technologies, such as electrostatic precipitators (ESPs) have been introduced to the market. The ESP has been used in buildings because it can remove particles while only causing low pressure drops. Moreover, ESPs can be either in-duct or standalone units. This review aims to provide an overview of ESP use, methods for testing this product, the performance of existing ESPs concerning removing pollutants and their byproducts, and the existing market for ESPs.

Sign in / Sign up

Export Citation Format

Share Document