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Wildland firefighters are exposed to airborne particulates, polycyclic aromatic hydrocarbons (PAHs), and other hazardous substances. Respiratory protection is indicated, but information is lacking on the tasks and conditions for which mask wearing should be advised. Studies to assess respiratory protection in wildland firefighters were carried out in western Canada in 2021 and 2023. Sampling pumps measured airborne exposures and urinary 1-hydroxypyrene (1-HP) was assayed to indicate PAH absorption. Participants in 2021 reported the time for which they wore the mask during each task. In 2023, the use of masks was reported, and firefighters rated the smoke intensity. In 2021, 72 firefighters were monitored over 164 shifts and, in 2023, 89 firefighters were monitored for 263 shifts. In 2021, mask wearing was highest for those engaged in initial attack and hot spotting. Urinary 1-HP at the end of rotation was highest for those reporting initial attack, working on a prescribed fire and mop-up. In 2023, firefighter ratings of smoke intensity were strongly associated with measured particulate mass and with urinary 1-HP, but masks were not worn more often when there was higher smoke intensity. The data from the literature did not provide a clear indication of high-exposure tasks. Better task/exposure information is needed for firefighters to make informed decisions about mask wearing.

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AIM/OBJECTIVES: Fit testing of N95/FFP2 respirators is universally recommended before exposure to airborne infectious diseases such as COVID-19. Respirator supply shortage in the COVID-19 pandemic encouraged extended-use for up to 4 h, despite uncertainty about seal integrity over time. The aim of our study was to assess N95 seal integrity after at least 2 h of continuous clinical use in the intensive care unit (ICU). We hypothesised that seal integrity would deteriorate over time, with variability between respirator shapes. METHODS: A prospective cohort study of healthcare workers in a metropolitan ICU setting in Australia between April 2021 and August 2022. Following consent and screening, participants underwent qualitative fit testing in the ICU, and fit tests were repeated following a continuous period of at least 2-h usage. The primary outcome was N95 fit-test failure rate measured by qualitative fit testing of >2 h compared to baseline. Secondary outcomes evaluated effects of respirator shape, demographic characteristics, and duration of respirator use on respirator fit after 2 h use. RESULTS: Fifty-one participants were recruited and consented. Six participants were excluded; four failed baseline fit test, one could not taste saccharin, and one did not complete 2 h of usage. Fourteen of 45 participants (∼31%) failed the extended-use fit test (median duration: 2 h 10 min [interquartile range: 2:07-2:20]). Fit-test rates differed between respirator shapes; three-piece flat-fold respirators had lower failure rates (6/32; 19%) than duckbill-shaped respirators (6/11; 55%) p = 0.046. No other demographic characteristic or respirator shape was significantly associated with increased failure rate. CONCLUSIONS: Following 2 h of use, approximately 30% of participants failed repeat fit testing, suggesting incomplete respiratory protection. Three-piece flat-fold respirators outperformed duckbill respirators. Extended use of respirators, even without respirator reuse, may put healthcare workers at risk of inadequate respiratory protection, in particular when using duckbill-shaped respirators.

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BACKGROUND: New elastomeric half-mask respirator (EHMR) models without exhalation valves (EVs) or with exhalation valve filters (EVFs) are facilitating expanded use in health settings to reduce workers' exposure to airborne hazards while acting as source control to prevent pathogen spread. The physical comfort of new models has not been assessed in comparison to previously used EHMRs with EVs. METHODS: Researchers assessed 1,962 health care and emergency medical service personnels' self-reported adverse experiences from 2 cohorts while wearing EHMR models with EVs (cohort 1, n = 1,080) and without EVs or with EVFs (cohort 2, n = 882). Fisher exact test identified differences between the cohorts accounting for organizational factors when possible. RESULTS: Cohort 1 respondents experienced communication challenges and discomfort when wearing the EHMR > 1 hour statistically significantly more often than cohort 2. Cohort 2 respondents reported statistically significantly more instances of difficulty breathing, moisture buildup, being uncomfortable to wear < 1 hour, and being uncomfortably warm. CONCLUSIONS: Discomfort is prevalent among end users and more often among those wearing EHMRs without an EV/with an EVF. As EHMR research and development advances, prevalence in use may increase for emergency and routine situations. Organizations may not only need guidance about respirator selection but also model-specific selection.

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In Europe, respiratory protective devices must be certified before they can be marketed. Among the parameters of interest, inward leakage (IL) characterizes the tightness between the face seal and the face, to verify that the device is well-designed. European standard EN 13274-1 (2001) and International Organization for Standardization (ISO) standard ISO 16900-1 (2019) specify that IL should be measured using sodium chloride (NaCl) aerosol or sulfur hexafluoride (SF6) gas. For reusable masks made of nonporous materials, both test agents are considered equally acceptable. However, the few studies that have compared IL values measured with various aerosols and gases have come to divergent conclusions. This work then aimed to measure IL with the test agents recommended by the standards to determine whether they are really equivalent. Since krypton (Kr) is an interesting candidate for replacing SF6 in standard tests, IL was assessed with SF6 and Kr simultaneously, and with NaCl aerosol using various calculation methods. Tests were carried out on 5 models of full-face masks donned on a headform connected to a breathing machine simulating 3 sinusoidal breathing rates of various intensities. The respirator fit on the headform was evaluated using a controlled negative pressure method to determine a manikin fit factor. Four scenarios were then tested to represent very poor, bad, good, and excellent fit. Gas concentration was measured using a mass spectrometer, and IL was calculated for SF6 and Kr. A combination of 3 devices allowed the determination of the number-based concentration of particles with diameters between 20 nm and 2 µm, and IL was calculated for each of the 33 channels, as well as using a cumulative number concentration. In addition, to comply with standards, a conversion was carried out to calculate IL using a cumulative mass concentration. The results of this work evidenced that the IL values measured with NaCl were systematically lower than those determined with gases. IL was also shown to vary with particle size, with a maximum value exceeding that calculated with cumulative concentrations (in number or mass). As part of the revision of the standards, protocols for measuring inward leakage should be redefined. On the one hand, acceptability thresholds should be re-evaluated according to the nature of the test agent (gas or aerosol), as it is clear that the 2 options do not give the same results for a given configuration. On the other hand, the aerosol leakage measurement protocol needs to be reworked to enable the measurement of a well-defined, robust, and reproducible inward leakage value.

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BACKGROUND: Facial-protective equipment (FPE) use increased during the SARS-CoV-2 pandemic. This study explored factors influencing home care personal support workers' (PSWs) and nurses' self-reported adherence to FPE. METHODS: A cross-sectional, electronic, survey was distributed to PSWs and nurses (1,108 complete responses) at 3 home care agencies in Ontario, Canada, in May to June 2022. Descriptive, bivariate, and multivariable analysis were used to assess individual, environmental, and organizational factors influencing adherence. RESULTS: Among participants (786 PSWs, 322 nurses), 64% reported being adherent to both respiratory and eye FPE (Respiratory: 96%, Eye: 64%). Higher adherence was associated with facility-based work; better knowledge of FPE; prepandemic FPE use; good availability and convenient access; strong organizational support for health and safety; and Caribbean identity. Lower adherence was found for men; nurses with 2-year diplomas; shorter length of employment; communal transportation; and experiencing negative mental health effects from workplace infectious disease exposure. DISCUSSION: Agencies should prioritize increasing providers' knowledge of FPE, supporting mental well-being, fostering a supportive culture, and ensuring availability of FPE. The influences of gender, ethnicity, and role require further exploration. CONCLUSIONS: FPE adherence may be improved by addressing modifiable factors and developing population-specific strategies.

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This study compared the effectiveness of N95 FFRs in providing respiratory protection for healthcare staff in a residential aged care facility (RACF) and tertiary teaching hospital (TTH) who had previously passed their occupational respiratory protection program fit test. A total of 126 healthcare workers who were regularly using N95 FFRs and who had previously passed a fit test participated in this comparative study. In this study, participants were again fit tested with the PortaCount machine, and their self-assessed tolerability of wearing an N95 FFR was assessed using a standardized questionnaire. The main outcome measures included the pass rate of the fit test and the assessment of tolerability and comfort of the N95 FFR. Across all participants, the fit test pass rate was low (27%), indicating persistent gaps in respiratory protection programs for healthcare workers during the ongoing COVID-19 pandemic. Hospital workers were 3.7 times more likely to pass the test compared to their counterparts in RACFs (p < 0.001). It was also found that workers in RACFs reported higher levels of discomfort and overall dissatisfaction with N95 FFRs compared to hospital staff. These findings highlight the need for targeted interventions and improvements in respiratory protection practices beyond annual fit testing, particularly in RACFs, to ensure the safety of healthcare workers and the vulnerable population they serve.

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The COVID-19 pandemic has transformed our understanding of aerosol transmissible disease and the measures required to minimise transmission. Anaesthesia providers are often in close proximity to patients and other hospital staff for prolonged periods while working in operating and procedure rooms. Although enhanced ventilation provides some protection from aerosol transmissible disease in these work areas, close proximity and long duration of exposure have the opposite effect. Surgical masks provide only minimal additional protection. Surgical patients are also at risk from viral and bacterial aerosols. Despite having recently experienced the most significant pandemic in 100 yr, we continue to lack adequate understanding of the true risks encountered from aerosol transmissible diseases in the operating room, and the best course of action to protect patients and healthcare workers from them in the future. Nevertheless, hospitals can take specific actions now by providing respirators for routine use, encouraging staff to utilise respirators routinely, establishing triggers for situations that require respirator use, educating staff concerning the prevention of aerosol transmissible diseases, and providing portable air purifiers for perioperative spaces with low levels of ventilation.

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BACKGROUND: Reusable elastomeric half-mask respirators (EHMR) are an alternative to address shortages of disposable respirators. While respirator discomfort has been noted as a barrier to adherence to wearing an N95 filtering facepiece respirator (FFR) among health care personnel (HCP), few have examined EHMR comfort while providing patient care, which was the purpose of this study. METHOD: Among a cohort of 183 HCP, we prospectively examined how HCP rated EHMR tolerability using the Respirator Comfort, Wearing Experience, and Function Instrument (R-COMFI) questionnaire at Study Week 2 and Week 10. At the completion of the study (Week-12), HCP compared EHMR comfort with their prior N95 FFR use. Overall R-COMFI scores and three subscales (comfort, wear experience, and function) were examined as well as individual item scores. FINDINGS: The HCP reported an improved overall R-COMFI score (lower score more favorable, 30.0 vs. 28.7/47, respectively) from Week 2 to Week 10. Many individual item scores improved or remained low over this period, except difficulty communicating with patients and coworkers. The overall R-COMFI scores for the EHMR were more favorable than for the N95 FFR (33.7 vs. 37.4, respectively), with a large proportion of workers indicating their perception that EHMR fit better, provided better protection, and they preferred to wear it in pandemic conditions compared with the N95 FFR. CONCLUSION/APPLICATION TO PRACTICE: Findings suggest that the EHMR is a feasible respiratory protection device with respect to tolerance. EHMRs can be considered as a possible alternative to the N95 FFR in the health care setting. Future work is needed in the EHMR design to improve communication.

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Halfmask air-purifying respirators are used by millions of workers to reduce inhaling air contaminants, both chemical (e.g., asbestos, styrene) and biological (e.g., SARS-CoV-2, Mycobacterium tuberculosis). In 2006, the federal Occupational Safety and Health Administration (OSHA) promulgated a standard that gave halfmask respirators an assigned protection factor (APF) of 10. This signified that OSHA assumes a fit-tested and trained wearer will experience a 10% maximum total inward leakage of contaminated air into the facepiece. To derive APF = 10, OSHA analyzed data from 16 workplace studies of the efficacy of halfmask respirators worn against particulate contaminants. In this commentary, I contend that, in considering the data, OSHA made several errors that overstated halfmask respirator efficacy. The errors were (i) failing to properly account for within-wearer and between-wearer variability in respirator efficacy; (ii) ignoring the effect of particle deposition in the respiratory tract; (iii) aggregating unbalanced data within and between studies, and effectively double-counting the data in some studies; and (iv) ignoring the effect that particle size exerts in penetrating respirator facepiece leak paths. The net result is that OSHA's APF = 10 can lead to excessive toxicant exposure for many workers.

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BACKGROUND: A rapid large-scale evaluation of a newly available duckbill style P2/N95 respirator, the Care Essentials (CE) MSK-003, was required to determine its suitability for deployment into the Victorian healthcare service. The aims of this study were to assess the feasibility of establishing a rapid, multi-organisational and multi-modal evaluation of the respirator, and to investigate whether this respirator would meet the needs of healthcare workers. METHODS: The evaluation was a collaboration among three healthcare organisations - two tertiary hospitals in metropolitan Melbourne and a rural-based hospital. Participants were healthcare workers undertaking their routine fit tests. They were required to complete quantitative fit testing and a usability assessment survey on the CE MSK-003 respirator. The a priori performance criteria were set as fit test pass rate of >70%, plus satisfactory subjective overall comfort and performance assessments, defined as a rating of adequate, good, or very good in >90% of the cohort. RESULTS: A total of 1070 participants completed the multi-modal assessment within a month. Seventy-eight percent of participants passed their quantitative fit test. Over 90% of survey respondents reported that the CE MSK-003 was adequate, good or very good in terms of its overall comfort and performance assessments. CONCLUSION: We demonstrated that a multi-modal evaluation of a new respirator can be rapidly conducted with a high level of participation in a controlled, consistent manner across multiple organisations. The evaluation results of the CE MSK-003 respirator exceeded our predetermined (a priori) minimal criteria, making it suitable for broad distribution to healthcare organisations.

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N95 respirators are the core equipment used by healthcare workers to prevent the spread of respiratory diseases. The protective effect of N95 against infection spread depends on the fit of the N95 to the wearer, which is related to the wearer's facial dimensions. The purpose of this cross-sectional study was to assess the relationship between the fit of three types of N95 and facial dimensions. A total of 305 healthcare workers from ten hospitals in Beijing were recruited for this study. Facial dimensions of workers were measured using Intel RealSense Depth Camera D435. Fit testing was conducted on three types of N95 using the TSI-8038 Porta Count Pro + Respirator Fit Tester. Possible associations between the fit test results and facial dimension data were examined. A Porta Count reading of 100 was used as the criterion for an acceptable fit. The fit of the folding respirators was positively correlated with nose length (r = 0.13, p = 0.02), nose height (r = 0.14, p = 0.02), and face width (r = 0.12, p = 0.03), whereas that of flat respirators was correlated with nose width (r = 0.16, p < 0.01), chin length (r = 0.18, p < 0.01), and pro-face width (r = 0.13, p = 0.02), and that of arched respirators was correlated with the nose length (r = 0.13, p = 0.03). The fit of N95 for wearers depends on their facial features. The results of this study can provide advice for medical workers to choose the appropriate N95. Medical staff should fully consider their facial dimensions when choosing an appropriate N95 to improve the protective efficacy of respirators and to reduce the risk of infection by respiratory diseases.

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BACKGROUND: During public health emergencies, demand for N95 filtering facepiece respirators (N95 FFRs) can outpace supply. Elastomeric half-mask respirators (EHMRs) are a potential alternative that are reusable and provide the same or higher levels of protection. This study sought to examine the practical aspects of EHMR use among health care personnel (HCP). METHODS: Between September and December 2021, 183 HCPs at 2 tertiary referral centers participated in this 3-month EHMR deployment, wearing the EHMR whenever respiratory protection was required according to hospital protocols (ie, when an N95 FFR would typically be worn) and responding to surveys about their experience. RESULTS: Participants wore EHMRs typically 1 to 3 hours per shift, reported disinfecting the respirator after 85% of the removals, and reported high confidence in using the EHMR following the study. EHMRs caused minimal interference with patient care tasks, though they did inhibit communication. DISCUSSION: HCP who had not previously worn an EHMR were able to wear it as an alternative to an N95 FFR without much-reported interference with their job tasks and with high disinfection compliance. CONCLUSIONS: This study highlights the feasibility of the deployment of EHMRs during a public health emergency when an alternative respirator option is necessary.

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BACKGROUND: One of the main infection prevention and control measures introduced during the COVID-19 pandemic was the focused application of respiratory protection to ensure health worker safety and the effective use of personal protective equipment. However, user acceptance of these strategies is paramount in sustainable compliance. This study explores various aspects of respirator use and provides recommendations to improve and maximize health worker safety. The aim of this study was to understand the relationship between respirator (P2/N95) comfort and user experience toward respiratory protection. The aim of this study was to understand the relationship between respirator (P2/N95) comfort and user experience toward respiratory protection. METHODS: The nonexperimental cross-sectional design study was conducted in New South Wales, Australia between November and December 2022 using an anonymous self-administered online questionnaire in Microsoft Forms. RESULTS: Of 2,514 respondents, 65% reported to have used a respirator every working day with only a few using a respirator once weekly or less (9%). Almost all respondents had completed at least one quantitative fit test (96%) prior to the survey. Fifty-nine percent reported to have experienced discomfort from wearing a respirator and the most reported adverse effect was difficulty communicating (64%), followed by skin irritation or acne (62%) and headache (56%). CONCLUSIONS: Despite somewhat less favorable ratings on comfort and communication, health workers are in favor of respiratory protection. However, a focus on tolerance of respirators and strategies to address adverse effects from prolonged respirator use must be considered when implementing policies and procedures. Moreover, resources must be allocated to improve the design, breathability, and sustainability of a respirator along with education and training on how to use respiratory protection safely and effectively.

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Editor's Note: This is a response to "Why a Workplace Barrier Face Covering is a Bad Idea" by Mark Nicas. DOI: 10.1177/10482911231193771.

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Editor's Note: This is a commentary on "Barrier Face Coverings for Workers" by Lisa Brosseau and Jeffrey Stull, which appeared in NEW SOLUTIONS 32(3).

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Objective To understand the respiratory protection competency of staff in hospitals.Methods Staff from six hospitals of different levels and characteristics in Beijing were selected,including doctors,nurses,medical technicians,and servicers,to conduct knowledge assessment on respiratory protection competency.According to exposure risks of respiratory infectious diseases,based on actual cases and daily work scenarios,content of respira-tory protection competency assessment was designed from three aspects:identification of respiratory infectious di-seases,transmission routes and corresponding protection requirements,as well as correct selection and use of masks.The assessment included 6,6,and 8 knowledge points respectively,with 20 knowledge points in total,all of which were choice questions.For multiple-choice questions,full marks,partial marks,and no mark were given respective-ly if all options were correct,partial options were correct and without incorrect options,and partial options were correct but with incorrect options.Difficulty and discrimination analyses on question of each knowledge point was conducted based on classical test theory.Results The respiratory protection competency knowledge assessment for 326 staff members at different risk levels in 6 hospitals showed that concerning the 20 knowledge points,more than 60％participants got full marks for 6 points,while the proportion of full marks for other questions was relatively low.Less than 10％participants got full marks for the following 5 knowledge points:types of airborne diseases,types of droplet-borne diseases,conventional measures for the prevention and control of healthcare-associated infec-tion with respiratory infectious diseases,indications for wearing respirators,and indications for wearing medical protective masks.Among the 20 knowledge questions,5,1,and 14 questions were relatively easy,medium,and difficult,respectively;6,1,4,and 9 questions were with discrimination levels of ≥0.4,0.30-0.39,0.20-0.29,and ≤0.19,respectively.Conclusion There is still much room for hospital staff to improve their respiratory protection competency,especially in the recognition of diseases with different transmission routes and the indications for wearing different types of masks.

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Both respirators and surgical masks (SM) are used as source control devices. During the COVID-19 pandemic, there was much interest in understanding the extent of particle total outward leakage (TOL) from these devices. The objective of this study was to quantify the TOL for five categories of devices: SMs, National Institute for Occupational Safety and Health (NIOSH) Approved N95 filtering facepiece respirators (FFRs) without exhalation valves, NIOSH Approved N95 FFRs with exhalation valves (N95 FFRV), NIOSH Approved elastomeric half-mask respirators (EHMRs) with exhalation valves, and NIOSH Approved EHMRs with an SM covering the exhalation valve (EHMRSM). A benchtop test system was designed to test two models of each device category. Each device was mounted on a headform at three faceseal levels (0% faceseal, 50% faceseal, and 100% faceseal). At each faceseal level, the TOL was assessed at three flow rates of minute ventilations of 17, 28, and 39 L/min. The experimental design was a split-split-plot configuration. Device type, faceseal level, flow rate, and the interaction of device type and faceseal level were found to have a significant effect (p-value < 0.05) on the TOL. This study found that the N95 FFRs without exhalation valves had the lowest mean TOL. The SMs had about three times higher TOL than the N95 FFRs without exhalation valves. The TOL of the N95 FFRV was comparable to that of the SM at 0% and 50% faceseal on average overall conditions, but the N95 FFRV had a significantly higher TOL than the SM at a 100% faceseal. The EHMRs had the highest TOL because of the exhalation valve. Using an SM to cover the exhalation valve did not improve the EHMRs' efficiency in mitigating the TOL. Caution should be exercised when using N95 FFRVs as a source control measure against respiratory activities with heavy work rates, such as performing CPR. Results of this study showed that reduced faceseal leakage for N95 FFRs and SMs improves source control.

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Loose-fitting powered air-purifying respirators (LF-PAPRs) are increasingly used in hospitals and coal mines because of their high comfort and protection level, but the utilization faces the challenges of 8-hr continuous high protection requirements in the hospital environment and the coupling effects of high temperature, high humidity, high dust concentration in coal mines. Based on the self-developed powered air-purifying respirator simulation test system, this study explores the 8-hr changes of supplied airflow, the relative air pressure inside the inlet covering (ΔP), and total inward leakage (TIL) of four models of LF-PAPRs in simulated hospital and coal mine environments. Results show that: (1) In a simulated hospital environment, all four LF-PAPRs showed filter cartridge blockage within 5 ∼ 6 hr of continuous operation; while in the simulated coal mine, three models of LF-PAPRs showed filter cartridge blockage within 3 hr. (2) In both the hospital and coal mine environments, there are cases where the supplied airflow of LF-PAPRs dropped below 170 L/min within 3 hr. (3) In a simulated hospital environment, the ΔP of all LF-PAPRs maintained positive within 5-6 hr; while in the simulated coal mine, the ΔP of two LF-PAPRs, respectively, appeared negative after 1 hr and 1.6 hr operation. (4) The maximum TIL of the tested LF-PAPRs, respectively ranged from 0.5-0.9% and 1.4-3% in simulated hospital and coal mine environments. (5) In both hospital and coal mine environments, the supplied airflow and ΔP of each LF-PAPR showed a decreasing trend with increasing test duration, while the TIL significantly increased with testing time. (6) The supplied airflow, ΔP, and TIL of each LF-PAPR in the simulated hospital environment performed better than those in the coal mine. This study evaluated the performance of PAPR under the most severe operating conditions, and respirator performance may differ under in-situ conditions.

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BACKGROUND: Wearing respiratory protective masks (RPMs) has become common worldwide, especially in healthcare settings, since the onset of the COVID-19 pandemic. Hypotheses have suggested that sound transmission could be limited by RPMs, which possibly affects the characteristics of acoustic energy and speech intelligibility. The objective of this study was to investigate the effect of RPMs on acoustic measurements through a systematic review with meta-analysis. METHODS: Five database searches were conducted, ranging from their inception to August 2023, as well as a manual search. Cross-sectional studies were included that provided data on widely used gender-independent clinical acoustic voice quality measures (jitter, shimmer, HNR, CPPS, and AVQI) and habitual sound pressure level (SPL). RESULTS: We found nine eligible research studies with a total of 422 participants who were compared both without masks and with different types of masks. All included studies focused on individuals with vocally healthy voices, while two of the studies also included those with voice disorders. The results from the meta-analysis were related to medical/surgical and FFP2/(K)N95 masks. None of the acoustic measurements showed significant differences between the absence and presence of masks (p > 0.05). When indirectly comparing both mask types, statistical significance was identified for parameters of jitter, HNR, CPPS and SPL (p < 0.001). CONCLUSIONS: The present meta-analysis indicates that certain types of RPMs have no significant influence on common voice quality parameters and SPL compared to recordings without masks. Nevertheless, it is plausible that significant differences in acoustic parameters might exist between different mask types. Consequently, it is advisable for the clinical practice to always use the same mask type when using RPMs to ensure high comparability and accuracy of measurement results.