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Karen S. Galea - One of the best experts on this subject based on the ideXlab platform.
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the effectiveness of Respiratory Protection worn by communities to protect from volcanic ash inhalation part i filtration efficiency tests
International Journal of Hygiene and Environmental Health, 2018Co-Authors: William Mueller, Claire J. Horwell, Susanne Steinle, Andrew Apsley, John W. Cherrie, Stephanie Mcpherson, Karen S. GaleaAbstract:Abstract During volcanic eruptions and their aftermath, communities may be concerned about the impacts of inhaling volcanic ash. Access to effective Respiratory Protection (RP) is therefore important for many people in volcanic areas all over the world. However, evidence to support the use of effective RP during such crises is currently lacking. The aim of this study was to build the first evidence base on the effectiveness of common materials used to protect communities from ash inhalation in volcanic crises. We obtained 17 forms of RP, covering various types of cloth through to disposable masks (typically used in occupational settings), which communities are known to wear during volcanic crises. The RP materials were characterised and subjected to filtration efficiency (FE) tests, which were performed with three challenge dusts: ashes from Sakurajima (Japan) and Soufriere Hills (Montserrat) volcanoes and aluminium oxide (Aloxite), chosen as a low-toxicity surrogate dust of similar particle size distribution. FE tests were conducted at two concentrations (1.5 mg/m3 and 2.5 mg/m3) and two flow rates (equivalent to 40 and 80 l/min through 15.9 cm2 sections of each RP type). Each material was held in a sample holder and PM2.5 dust concentrations were measured both outside the mask material and inside the sample holder to determine FE. A limited number of tests were undertaken to assess the effect on FE of wetting a bandana and a surgical mask, as well as folding a bandana to provide multiple filter layers. Overall, four RP materials performed very well against volcanic ash, with median FEs in excess of 98% (N95-equiv., N99-equiv., PM2.5 surgical (Japan), and Basic flat-fold (Indonesia)). The two standard surgical masks tested had median FEs of 89–91%. All other materials had median FEs ranging from 23 to 76% with no cloth materials achieving >44%. Folding a bandana resulted in better FE (40%; 3× folded) than single-layered material (29%). Wetting the bandana and surgical mask material did not improve FE overall. This first evidence base on the FE of common materials used to protect communities in volcanic crises from ash inhalation has been extended in a companion study ( Steinle et al., 2018 ) on the total inward leakage of the best-performing masks when worn by human volunteers. This will provide a complete assessment of the effectiveness of these RP types.
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The effectiveness of Respiratory Protection worn by communities to protect from volcanic ash inhalation. Part II: Total inward leakage tests.
International journal of hygiene and environmental health, 2018Co-Authors: Susanne Steinle, Claire J. Horwell, William Mueller, Anne Sleeuwenhoek, Andrew Apsley, Alice Davis, John W. Cherrie, Karen S. GaleaAbstract:Inhalation of ash can be of great concern for affected communities, during and after volcanic eruptions. Governmental and humanitarian agencies recommend and distribute a variety of Respiratory Protection (RP), most commonly surgical masks. However, there is currently no evidence on how effective such masks are in protecting wearers from volcanic ash. In Part I of this study (Mueller et al., 2018), we assessed the filtration efficiency (FE) of 17 materials from different forms of RP against volcanic ash and a surrogate, low-toxicity dust, Aloxite. Based on those results, we now present the findings from a volunteer simulation study to test the effect of facial fit through assessment of Total Inward Leakage (TIL). Four different disposable RP types that demonstrated very high median FE (≥96% for Aloxite; ≥89% for volcanic ash) were tested without provision of training on fit. These were an industry-certified mask (N95-equiv.); a surgical mask from Japan designed to filter PM2.5; a flat-fold basic mask from Indonesia; and a standard surgical mask from Mexico, which was also tested with an added medical bandage on top, as an additional intervention to improve fit. Ten volunteers (6 female, 4 male) were recruited. Each RP type was worn by volunteers under two different conditions simulating cleaning-up activities during/after volcanic ashfall. Each activity lasted 10 min and two repeats were completed for each RP type per activity. Dust (as PM2.5) concentration inside and outside the mask was measured with two TSI SidePak aerosol monitors (Models AM510 and AM520, TSI, Minnesota, USA) to calculate TIL. A questionnaire was administered after each test to collect perceptions of fit, comfort, Protection and breathability. The best-performing RP type, across both activities, was the industry-certified N95-equiv. mask with 9% mean TIL. The standard surgical mask and the basic flat-fold mask both performed worst (35% TIL). With the additional bandage intervention, the surgical mask mean TIL improved to 24%. The PM2.5 surgical mask performed similarly, with 22% TIL. The N95-equiv. mask was perceived to provide the best Protection, but was also perceived as being uncomfortable and more difficult to breathe through. This study provides a first objective evidence base for the effectiveness of a selection of RP types typically worn around the world during volcanic crises. The findings will help agencies to make informed decisions on the procurement and distribution of RP in future eruptions.
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Short Communication: Health Interventions in Volcanic Eruptions—Community Wearability Assessment of Respiratory Protection against Volcanic Ash from Mt Sinabung, Indonesia
MDPI AG, 2018Co-Authors: Karen S. Galea, Judith Covey, Sari Mutia Timur, Claire J. Horwell, Fentiny Nugroho, William MuellerAbstract:Inhalation of ash can be of great concern for affected communities, during and after volcanic eruptions. Governmental and humanitarian agencies recommend and distribute a variety of Respiratory Protection (RP), commonly surgical masks but, also, industry-certified N95-style masks. However, there is currently no evidence on how wearable they are within affected populations or how protective wearers perceive them being against volcanic ash (which will influence the likelihood of uptake of recommended interventions). Volunteers living near Mt. Sinabung, Sumatra, Indonesia, participated in a field wearability study, which included a high-efficiency mask certified to industry standards (N95-equiv.); a standard, pleated surgical mask (Surgical); a Basic flat-fold mask (Flat-fold), and the surgical mask plus a scarf tied over the top (Surgical Plus) to improve fit. These types of RP had all performed well during earlier laboratory filtration efficiency tests. The N95-equiv. mask had performed significantly better than the other RP in the subsequent total inward leakage volunteer trials, whilst the Flat-fold and Surgical masks performed poorly, letting in a third of PM2.5 particles (data published elsewhere). Thirty volunteers wore each mask for a 15-min walk before being asked to rate the comfort, breathability and perceived Protection and fit of each. After wearing all of the masks, volunteers compared and identified their preferred type of Protection. The feedback received from the volunteers suggested that the Surgical Plus and N95-equiv. masks were rated as being significantly hotter and more humid than other masks. The Flat-fold was rated to have better breathability than the other masks. The N95-equiv. mask was ranked as providing the best level of effectiveness of the four masks tested. Ultimately, when asked which type of mask they would choose to wear during ashfall, 33% selected the Flat-fold mask due to its comfort and simplicity, with the Surgical Plus being the least likely to be chosen of the four tested. The study findings are of benefit to agencies who need to make informed decisions on the procurement and distribution of RP for use by those affected in future eruptions and the provision of advice to communities on their usage
David Y H Pui - One of the best experts on this subject based on the ideXlab platform.
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alternative face masks made of common materials for general public fractional filtration efficiency and breathability perspective
Aerosol and Air Quality Research, 2020Co-Authors: Chenxing Pei, Sheng Chieh Chen, Seong Chan Kim, David Y H PuiAbstract:As COVID-19 pandemic has caused more than 24 million confirmed cases globally (as of August 28th, 2020), it is critical to slow down the spreading of SARS-CoV-2 to protect the healthcare system from overload Wearing a respirator or a mask has been proven as an effective method to protect both the wearer and others, but commercially available respirators and masks should be reserved for healthcare workers under a currently desperate shortage The use of alternative materials becomes an option for the general public to make the do-it-yourself (DIY) masks, with their efficacy seldom reported In this study, we tested commercial respirators and masks, furnace filters, vacuum cleaner filters, and common household materials We evaluated the materials’ fractional filtration efficiency and breathing resistance, which are primary factors affecting Respiratory Protection To compare the efficiency-resistance tradeoff, the figure of merit of each tested common material was also calculated Filter media with electrostatic charges (electret) is recommended due to its high efficiency with low flow resistance;multiple-layer household fabrics and sterilization wraps are acceptable materials;a coffee filter is inadvisable due to its low efficiency The outcome of this study can not only offer guidance for the general public under the current pandemic but also suggest the appropriate alternative Respiratory Protection materials under heavy air pollution episodes © The Author(s)
Sergey A. Grinshpun - One of the best experts on this subject based on the ideXlab platform.
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inhalation exposure and Respiratory Protection of home healthcare workers administering aerosolized medications simulation study
Aerosol and Air Quality Research, 2019Co-Authors: Katherine Ollier, Tiina Reponen, Michael Yermakov, Maija Leppanen, Bingbing Wu, Nicholas Newman, Sergey A. GrinshpunAbstract:There is little information regarding aerosol exposure from using medical nebulizers and the factors affecting the risk of exposure, especially for treatments performed in a patient’s home environment. Home healthcare workers (HHWs) are a rapidly growing work population often exposed to aerosol hazards. Thus, we designed a simulated environment to measure the aerosol inhalation exposure of an HHW administering pressure-nebulized medications. We determined the relative contributions of different factors to aerosol reduction, namely, the room air exchange rate, proximity to the patient, and patient breathing rate, in an exposure chamber simulating a patient’s bedroom. Additionally, the performance of Respiratory protective devices worn by an HHW, a surgical mask and N95 filtering facepiece respirator (FFR), was evaluated using NaCl as a well-established surrogate. The particle concentration in the breathing zone of an unprotected worker ranged from 7,118 to 284,600 cm–3. The proximity to the aerosol source affected the aerosol concentration, but the influence of this factor diminished when the distance increased beyond 24 inches. For an unprotected HHW, ventilation was the most effective way to reduce exposure to nebulizer-produced medical aerosols. An increase in the air exchange rate from 0 to 5 h–1 significantly reduced the exposure; however, a further increase (to 17 h–1) produced only a small reduction in the particle concentration. Therefore, no evidence suggests that patient homes require extremely efficient ventilation to mitigate HHWs’ exposure to nebulizer-produced medications. Increasing the patient’s breathing flow rate reduced the aerosol inhalation exposure; however, this factor cannot be controlled, which weakens its practical viability. Wearing Respiratory Protection devices was found to be the most efficient way to reduce aerosol exposure (within the set of tested variables). As expected, an N95 FFR with a proper seal was about 20-fold more efficient than a surgical mask.
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surgical smoke simulation study physical characterization and Respiratory Protection
Aerosol Science and Technology, 2018Co-Authors: Yousef Elmashae, Tiina Reponen, Richard H Koehler, Michael Yermakov, Sergey A. GrinshpunAbstract:Exposure of operating room (OR) personnel to surgical smoke, a unique aerosol generated from the common use of electrocautery during surgical procedures, is an increasing health risk concern. The main objective of this simulation study was to characterize the surgical smoke exposure in terms of the particle number concentration and size distribution in a human breathing zone. Additionally, the performance of Respiratory protective devices designed for ORs was examined using two commercially available N95 facepiece filtering respirators (FFRs) as well as the same FFRs modified with new faceseal technology. The tests were conducted in an OR-simulating exposure chamber with the surgical smoke generated by electrocautery equipment applied to animal tissue and measured in the breathing zone with four aerosol spectrometers. The simulated workplace Protection factor of each tested respirator was determined for ten subjects by measuring the total aerosol concentrations inside and outside of a respirator. The peak of the particle size distribution was in a range of 60-150 nm. The concentration of particles generated during the simulated surgical procedure significantly exceeded the background concentration under all tested air exchange conditions. The data suggest that wearing N95 filtering facepiece respirators significantly decreased the human exposure to surgical smoke. The new faceseal technology provided significantly higher Respiratory Protection than the commercial N95 FFRs.
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how does breathing frequency affect the performance of an n95 filtering facepiece respirator and a surgical mask against surrogates of viral particles
Journal of Occupational and Environmental Hygiene, 2014Co-Authors: Tiina Reponen, Roy T Mckay, Sergey A. GrinshpunAbstract:Breathing frequency (breaths/min) differs among individuals and levels of physical activity. Particles enter respirators through two principle penetration pathways: faceseal leakage and filter penetration. However, it is unknown how breathing frequency affects the overall performance of N95 filtering facepiece respirators (FFRs) and surgical masks (SMs) against viral particles, as well as other health-relevant submicrometer particles. A FFR and SM were tested on a breathing manikin at four mean inspiratory flows (MIFs) (15, 30, 55, and 85 L/min) and five breathing frequencies (10, 15, 20, 25, and 30 breaths/min). Filter penetration (Pfilter) and total inward leakage (TIL) were determined for the tested Respiratory Protection devices against sodium chloride (NaCl) aerosol particles in the size range of 20 to 500 nm. “Faceseal leakage-to-filter” (FLTF) penetration ratios were calculated. Both MIF and breathing frequency showed significant effects (p < 0.05) on Pfilter and TIL. Increasing breathing frequency...
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do n95 respirators provide 95 Protection level against airborne viruses and how adequate are surgical masks
American Journal of Infection Control, 2006Co-Authors: Tiina Reponen, Anna Balazy, Mika Toivola, Atin Adhikari, Satheesh K Sivasubramani, Sergey A. GrinshpunAbstract:Background Respiratory Protection devices are used to protect the wearers from inhaling particles suspended in the air. Filtering face piece respirators are usually tested utilizing nonbiologic particles, whereas their use often aims at reducing exposure to biologic aerosols, including infectious agents such as viruses and bacteria. Methods The performance of 2 types of N95 half-mask, filtering face piece respirators and 2 types of surgical masks were determined. The collection efficiency of these Respiratory Protection devices was investigated using MS2 virus (a nonharmful simulant of several pathogens). The virions were detected in the particle size range of 10 to 80 nm. Results The results indicate that the penetration of virions through the National Institute for Occupational Safety and Health (NIOSH)-certified N95 respirators can exceed an expected level of 5%. As anticipated, the tested surgical masks showed a much higher particle penetration because they are known to be less efficient than the N95 respirators. The 2 surgical masks, which originated from the same manufacturer, showed tremendously different penetration levels of the MS2 virions: 20.5% and 84.5%, respectively, at an inhalation flow rate of 85 L/min. Conclusion The N95 filtering face piece respirators may not provide the expected Protection level against small virions. Some surgical masks may let a significant fraction of airborne viruses penetrate through their filters, providing very low Protection against aerosolized infectious agents in the size range of 10 to 80 nm. It should be noted that the surgical masks are primarily designed to protect the environment from the wearer, whereas the respirators are supposed to protect the wearer from the environment.
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Respiratory Protection provided by n95 filtering facepiece respirators against airborne dust and microorganisms in agricultural farms
Journal of Occupational and Environmental Hygiene, 2005Co-Authors: Atin Adhikari, Sergey A. Grinshpun, Roy T Mckay, Rakesh Shukla, Haoyue Zeigler, Tiina ReponenAbstract:An ew system was used to determine the workplace Protection factors (WPF) for dust and bioaerosols in agricultural environments. The field study was performed with a subject wearing an N95 filtering facepiece respirator while performing animal feeding, grain harvesting and unloading, and routine investigation of facilities. As expected, the geometric means (GM) of the WPFs increased with increasing particle size ranging from 21 for 0.7‐1 µm particles to 270 for 5‐10 µm particles (p < 0.001). The WPF for total culturable fungi (GM = 35) was significantly greater than for total culturable bacteria (GM = 9) (p = 0.01). Among the different microorganism groups, the WPFs of Cladosporium, culturable fungi, and total fungi were significantly correlated with the WPFs of particles of the same sizes. As compared with the WPFs for dust particles, the WPFs for bioaerosols were found more frequently below 10, which is a recommended assigned Protection factor (APF) for N95 filtering facepiece respirators. More than 50% of the WPFs for microorganisms (mean aerodynamic diameter <5 µm) were less than the proposed APF of 10. Even lower WPFs were calculated after correcting for dead space and lung deposition. Thus, the APF of 10 for N95 filtering facepiece respirators seems inadequate against microorganisms (mean aerodynamic size <5 µm). These results provide useful pilot data to establish guidelines for Respiratory Protection against airborne dust and microorganisms on agricultural farms. The method is a promising tool for further epidemiological and intervention studies in agricultural and other similar occupational and nonoccupational environments.
Sheng Chieh Chen - One of the best experts on this subject based on the ideXlab platform.
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alternative face masks made of common materials for general public fractional filtration efficiency and breathability perspective
Aerosol and Air Quality Research, 2020Co-Authors: Qisheng Ou, Sheng Chieh ChenAbstract:ABSTRACT As COVID-19 pandemic has caused more than 24 million confirmed cases globally (as of August 28th, 2020), it is critical to slow down the spreading of SARS-CoV-2 to protect the healthcare system from overload. Wearing a respirator or a mask has been proven as an effective method to protect both the wearer and others, but commercially available respirators and masks should be reserved for healthcare workers under a currently desperate shortage. The use of alternative materials becomes an option for the general public to make the do-it-yourself (DIY) masks, with their efficacy seldom reported. In this study, we tested commercial respirators and masks, furnace filters, vacuum cleaner filters, and common household materials. We evaluated the materials’ fractional filtration efficiency and breathing resistance, which are primary factors affecting Respiratory Protection. To compare the efficiency-resistance tradeoff, the figure of merit of each tested common material was also calculated. Filter media with electrostatic charges (electret) is recommended due to its high efficiency with low flow resistance; multiple-layer household fabrics and sterilization wraps are acceptable materials; a coffee filter is inadvisable due to its low efficiency. The outcome of this study can not only offer guidance for the general public under the current pandemic but also suggest the appropriate alternative Respiratory Protection materials under heavy air pollution episodes.
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alternative face masks made of common materials for general public fractional filtration efficiency and breathability perspective
Aerosol and Air Quality Research, 2020Co-Authors: Chenxing Pei, Sheng Chieh Chen, Seong Chan Kim, David Y H PuiAbstract:As COVID-19 pandemic has caused more than 24 million confirmed cases globally (as of August 28th, 2020), it is critical to slow down the spreading of SARS-CoV-2 to protect the healthcare system from overload Wearing a respirator or a mask has been proven as an effective method to protect both the wearer and others, but commercially available respirators and masks should be reserved for healthcare workers under a currently desperate shortage The use of alternative materials becomes an option for the general public to make the do-it-yourself (DIY) masks, with their efficacy seldom reported In this study, we tested commercial respirators and masks, furnace filters, vacuum cleaner filters, and common household materials We evaluated the materials’ fractional filtration efficiency and breathing resistance, which are primary factors affecting Respiratory Protection To compare the efficiency-resistance tradeoff, the figure of merit of each tested common material was also calculated Filter media with electrostatic charges (electret) is recommended due to its high efficiency with low flow resistance;multiple-layer household fabrics and sterilization wraps are acceptable materials;a coffee filter is inadvisable due to its low efficiency The outcome of this study can not only offer guidance for the general public under the current pandemic but also suggest the appropriate alternative Respiratory Protection materials under heavy air pollution episodes © The Author(s)
William Mueller - One of the best experts on this subject based on the ideXlab platform.
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the effectiveness of Respiratory Protection worn by communities to protect from volcanic ash inhalation part i filtration efficiency tests
International Journal of Hygiene and Environmental Health, 2018Co-Authors: William Mueller, Claire J. Horwell, Susanne Steinle, Andrew Apsley, John W. Cherrie, Stephanie Mcpherson, Karen S. GaleaAbstract:Abstract During volcanic eruptions and their aftermath, communities may be concerned about the impacts of inhaling volcanic ash. Access to effective Respiratory Protection (RP) is therefore important for many people in volcanic areas all over the world. However, evidence to support the use of effective RP during such crises is currently lacking. The aim of this study was to build the first evidence base on the effectiveness of common materials used to protect communities from ash inhalation in volcanic crises. We obtained 17 forms of RP, covering various types of cloth through to disposable masks (typically used in occupational settings), which communities are known to wear during volcanic crises. The RP materials were characterised and subjected to filtration efficiency (FE) tests, which were performed with three challenge dusts: ashes from Sakurajima (Japan) and Soufriere Hills (Montserrat) volcanoes and aluminium oxide (Aloxite), chosen as a low-toxicity surrogate dust of similar particle size distribution. FE tests were conducted at two concentrations (1.5 mg/m3 and 2.5 mg/m3) and two flow rates (equivalent to 40 and 80 l/min through 15.9 cm2 sections of each RP type). Each material was held in a sample holder and PM2.5 dust concentrations were measured both outside the mask material and inside the sample holder to determine FE. A limited number of tests were undertaken to assess the effect on FE of wetting a bandana and a surgical mask, as well as folding a bandana to provide multiple filter layers. Overall, four RP materials performed very well against volcanic ash, with median FEs in excess of 98% (N95-equiv., N99-equiv., PM2.5 surgical (Japan), and Basic flat-fold (Indonesia)). The two standard surgical masks tested had median FEs of 89–91%. All other materials had median FEs ranging from 23 to 76% with no cloth materials achieving >44%. Folding a bandana resulted in better FE (40%; 3× folded) than single-layered material (29%). Wetting the bandana and surgical mask material did not improve FE overall. This first evidence base on the FE of common materials used to protect communities in volcanic crises from ash inhalation has been extended in a companion study ( Steinle et al., 2018 ) on the total inward leakage of the best-performing masks when worn by human volunteers. This will provide a complete assessment of the effectiveness of these RP types.
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The effectiveness of Respiratory Protection worn by communities to protect from volcanic ash inhalation. Part II: Total inward leakage tests.
International journal of hygiene and environmental health, 2018Co-Authors: Susanne Steinle, Claire J. Horwell, William Mueller, Anne Sleeuwenhoek, Andrew Apsley, Alice Davis, John W. Cherrie, Karen S. GaleaAbstract:Inhalation of ash can be of great concern for affected communities, during and after volcanic eruptions. Governmental and humanitarian agencies recommend and distribute a variety of Respiratory Protection (RP), most commonly surgical masks. However, there is currently no evidence on how effective such masks are in protecting wearers from volcanic ash. In Part I of this study (Mueller et al., 2018), we assessed the filtration efficiency (FE) of 17 materials from different forms of RP against volcanic ash and a surrogate, low-toxicity dust, Aloxite. Based on those results, we now present the findings from a volunteer simulation study to test the effect of facial fit through assessment of Total Inward Leakage (TIL). Four different disposable RP types that demonstrated very high median FE (≥96% for Aloxite; ≥89% for volcanic ash) were tested without provision of training on fit. These were an industry-certified mask (N95-equiv.); a surgical mask from Japan designed to filter PM2.5; a flat-fold basic mask from Indonesia; and a standard surgical mask from Mexico, which was also tested with an added medical bandage on top, as an additional intervention to improve fit. Ten volunteers (6 female, 4 male) were recruited. Each RP type was worn by volunteers under two different conditions simulating cleaning-up activities during/after volcanic ashfall. Each activity lasted 10 min and two repeats were completed for each RP type per activity. Dust (as PM2.5) concentration inside and outside the mask was measured with two TSI SidePak aerosol monitors (Models AM510 and AM520, TSI, Minnesota, USA) to calculate TIL. A questionnaire was administered after each test to collect perceptions of fit, comfort, Protection and breathability. The best-performing RP type, across both activities, was the industry-certified N95-equiv. mask with 9% mean TIL. The standard surgical mask and the basic flat-fold mask both performed worst (35% TIL). With the additional bandage intervention, the surgical mask mean TIL improved to 24%. The PM2.5 surgical mask performed similarly, with 22% TIL. The N95-equiv. mask was perceived to provide the best Protection, but was also perceived as being uncomfortable and more difficult to breathe through. This study provides a first objective evidence base for the effectiveness of a selection of RP types typically worn around the world during volcanic crises. The findings will help agencies to make informed decisions on the procurement and distribution of RP in future eruptions.
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Short Communication: Health Interventions in Volcanic Eruptions—Community Wearability Assessment of Respiratory Protection against Volcanic Ash from Mt Sinabung, Indonesia
MDPI AG, 2018Co-Authors: Karen S. Galea, Judith Covey, Sari Mutia Timur, Claire J. Horwell, Fentiny Nugroho, William MuellerAbstract:Inhalation of ash can be of great concern for affected communities, during and after volcanic eruptions. Governmental and humanitarian agencies recommend and distribute a variety of Respiratory Protection (RP), commonly surgical masks but, also, industry-certified N95-style masks. However, there is currently no evidence on how wearable they are within affected populations or how protective wearers perceive them being against volcanic ash (which will influence the likelihood of uptake of recommended interventions). Volunteers living near Mt. Sinabung, Sumatra, Indonesia, participated in a field wearability study, which included a high-efficiency mask certified to industry standards (N95-equiv.); a standard, pleated surgical mask (Surgical); a Basic flat-fold mask (Flat-fold), and the surgical mask plus a scarf tied over the top (Surgical Plus) to improve fit. These types of RP had all performed well during earlier laboratory filtration efficiency tests. The N95-equiv. mask had performed significantly better than the other RP in the subsequent total inward leakage volunteer trials, whilst the Flat-fold and Surgical masks performed poorly, letting in a third of PM2.5 particles (data published elsewhere). Thirty volunteers wore each mask for a 15-min walk before being asked to rate the comfort, breathability and perceived Protection and fit of each. After wearing all of the masks, volunteers compared and identified their preferred type of Protection. The feedback received from the volunteers suggested that the Surgical Plus and N95-equiv. masks were rated as being significantly hotter and more humid than other masks. The Flat-fold was rated to have better breathability than the other masks. The N95-equiv. mask was ranked as providing the best level of effectiveness of the four masks tested. Ultimately, when asked which type of mask they would choose to wear during ashfall, 33% selected the Flat-fold mask due to its comfort and simplicity, with the Surgical Plus being the least likely to be chosen of the four tested. The study findings are of benefit to agencies who need to make informed decisions on the procurement and distribution of RP for use by those affected in future eruptions and the provision of advice to communities on their usage