Powered Air-purifying Respirators Research Articles

Personal protective equipment for preventing asbestos exposure in workers.

Personal protective equipment for preventing asbestos exposure in workers.

The Influence Of Knowledge Towards Physicians’ Intention To Use Powered Air-Purifying Respirators As Advanced Personal Protective Equipment Mediated By Health Belief Model During Covid-19 Pandemic

The COVID-19 has become a devastating occurrence and an urgent intervention for public health in Indonesia. Until the beginning of 2021, Indonesia has the highest number of healthcare workers deaths in Asia and fifth in the world. One of the reasons that resulted in a high number of deaths is due to the lack of personal protective equipment (PPE) to be worn in high-risk environments. Powered Air-Purifying Respirator (PAPR) is one of the most advanced protective equipment and recommended by many countries for their healthcare workers in handling COVID-19 pandemic. This research is conducted to predict Indonesian physicians’ intention to use PAPR as advanced PPE using the Health Belief Model. This research is a correlational study and a quantitative research using statistical tests in processing the data collected from online questionnaires. The findings collected from 163 respondents demonstrated that physicians in Indonesia have the intention to use PAPR as advanced PPE against COVID-19 based on their knowledge, perceived susceptibility, perceived severity, and perceived benefits of using PAPR. Perceived barriers do not have a significant influence towards physicians’ intention to use. The impact of knowledge to intention to use mediated by perceived benefits has the strongest correlation. This empirical model has moderate predictive accuracy with medium predictive relevance, therefore it could be developed and tested on an extended population. There are few managerial implications that could be recommended for hospital managers, public health administrators, and medical device suppliers to encourage physicians’ behavior. Several recommendations are given for further research development.
 Keywords: Health Belief Model, Knowledge, Perceived Susceptibility, Perceived Benefits, Perceived Severity, Perceived Barriers, Powered Air-Purifying Respirator, Protective Personal Equipment

Optimization of Impeller Structure Parameters of a Centrifugal Fan in a Powered Air-Purifying Respirator Power System

As the core power element of a centrifugal fan, the impeller’s structural parameters are important factors affecting the aerodynamic performance of the fan. Therefore, to improve the aerodynamic performance of centrifugal fans, in this study, we take the Powered Air-Purifying Respirator (PAPR) power system as the object of research and use a combination of computational fluid dynamics (CFD) and experimental validation to investigate the effects of the number of blades, blade inlet angle, blade outlet angle, blade height, and blade thickness on the aerodynamic performance of the fan. A five-factor, four-level orthogonal test table L16 (45) was selected to obtain the optimal combination of structural parameters for the impeller. In addition, in order to identify and visualize the features of the vortex, Q Criterion Normalized is applied to the simulation on the basis that the minimum pressure appears in the vortex core. In this study, Q Criterion Normalized is used to compare the internal vorticity of the prototype with that of the optimized prototype. The results show that (i) the order of influence of each parameter on the aerodynamic performance of the centrifugal fan is blade height > blade outlet angle > blade inlet angle > number of blades > blade thickness; (ii) the optimal combination of the structural parameters is number of blades 48, blade inlet angle 80°, blade outlet angle 120°, blade thickness 0.6 mm, and blade height 23 mm; the optimized prototype has an increase in air pressure of about 10%, an increase in air volume of about 31%, and an increase in efficiency from 49.61% to 53.57%; (iii) the intensity of internal vortices in the optimized prototype is weakened, the size of vortices and the number of vortices are reduced, and the homogeneity of the flow field is also improved.

Real-Time Tracheal Ultrasound vs. Capnography for Intubation Confirmation during CPR Wearing a Powered Air-Purifying Respirator in COVID-19 Era.

This study aimed to compare the accuracy of real-time trans-tracheal ultrasound (TTUS) with capnography to confirm intubation in cardiopulmonary resuscitation (CPR) while wearing a powered air-purifying respirator (PAPR). This setting reflects increased caution due to contagious diseases. This single-center, prospective, comparative study enrolled patients requiring CPR while wearing a PAPR who visited the emergency department of a tertiary medical center from December 2020 to August 2022. A physician performed the TTUS in real time and recorded the tube placement assessment. Another healthcare provider attached waveform capnography to the tube and recorded end-tidal carbon dioxide (EtCO2) after five ventilations. The accuracy and agreement of both methods compared with direct laryngoscopic visualization of tube placement, and the time taken by both methods was evaluated. Thirty-three patients with cardiac arrest were analyzed. TTUS confirmed tube placement with 100% accuracy, sensitivity, and specificity, whereas capnography demonstrated 97% accuracy, 96.8% sensitivity, and 100% specificity. The Kappa values for TTUS and capnography compared to direct visualization were 1.0 and 0.7843, respectively. EtCO2 was measured in 45 (37-59) seconds (median (interquartile range)), whereas TTUS required only 12 (8-23) seconds, indicating that TTUS was significantly faster (p < 0.001). No significant correlation was found between the physician's TTUS proficiency and image acquisition time. This study demonstrated that TTUS is more accurate and faster than EtCO2 measurement for confirming endotracheal tube placement during CPR, particularly in the context of PAPR usage in pandemic conditions.

Development of Antibacterial Hood and Filter for Medical Powered Air Purifying Respirators (PAPR)

Development of Antibacterial Hood and Filter for Medical Powered Air Purifying Respirators (PAPR)

Toward an engineering alternative to lockdown against COVID-19 and other airborne infectious diseases (Preprint)

Toward an engineering alternative to lockdown against COVID-19 and other airborne infectious diseases (Preprint)

Research on the air supply adjustment technology of breath-following powered air-purifying respirators

In the hope of reducing the air supply flow of the powered air-purifying respirator (PAPR) and extending the service life of the filter, a breath-following powered air-purifying respirator (BF-PAPR) that can dynamically adjust the air supply flow according to the breathing flow is proposed. The BF-PAPR changes the air supply flow by adjusting the speed of the variable-frequency centrifugal fan according to the air velocity at the half mask outlet (vhm) monitored by the modular wind speed transmitter. In the study, the air supply flow adjustment model of the BF-PAPR is developed. It is found that the filtration resistance barely influences vhm. In addition, under the same mean inhalation flow, the minimum outlet air velocity increases first and then decreases with the increase of the duty cycle variation coefficient (λ), while the maximum outlet air velocity decreases first and then increases. Moreover, the minimum air supply flow of the BF-PAPR is achieved when the standard value of the air velocity is 13.4 m/s and the value of λ is 1. The BF-PAPR can reduce the air supply flow by 6.5%-8.6% and the energy consumption by approximately 20% compared with the PAPR, which is beneficial for reducing the usage cost and extending the continuous working time.

Welding Fume: A Comparison Study of Industry Used Control Methods

Welding fume is generated during welding activities and is a known cancer-causing hazard for those working in the welding industry. Worker exposure has been shown to regularly exceed the applicable workplace exposure standard, and control measures are required to reduce worker exposure. The aim of this study is to compare the effectiveness of control measures to prevent welding fume exposure to workers. To achieve this aim, three common welding fume control measures (local exhaust ventilation (LEV), powered air purifying respirators (PAPRs) and on-gun extraction) were used during four different welding tasks. Compared to using no controls, LEV hood capture is likely to reduce welding fume concentrations in the breathing zone of a welder by up to a factor of 9. The use of on-gun LEV is likely to reduce welding fume concentrations in the breathing zone of a welder by up to a factor of 12. The 5th percentile effective protection factors of the PAPR for all sampled welding activities were considerably greater than the required minimum protection factor of 50 specified in AS/NZS 1715:2009 for powered air purifying respirators (PAPRs) with class PAPR-P3 particulate filters with any head covering.

A manikin-based assessment of loose-fitting powered air-purifying respirator performance at variable flow rates and work rates

Loose-fitting powered air-purifying respirators (PAPRs) are used in healthcare settings, although barriers to routine, everyday usage remain, including usability concerns and potential interference with work activities. Loose-fitting PAPRs are approved by the National Institute for Occupational Safety and Health (NIOSH) and must meet minimum performance requirements, including a minimum airflow requirement of 170 L/min. One course of action to address usability concerns is to allow for the use of PAPRs designed with reduced airflow rates. The primary objective of this study was to assess the effect of PAPR flow rate and user work rate on PAPR performance, using a manikin-based assessment method. PAPR performance was quantified using the “Manikin Fit Factor” (mFF), a ratio of the challenge aerosol concentration to the in-facepiece concentration. Flow rates from 50–215 L/min and low, moderate, and high work rates were tested. Two models of NIOSH Approved loose-fitting facepiece PAPRs were tested, both having an Occupational Safety and Health Administration Assigned Protection Factor (APF) or expected level of protection, of 25. A two-way analysis of variance with an effect size model was run for each PAPR model to analyze the effects of work rate and flow rate on PAPR performance. Flow rate and work rate were found to be significant variables impacting PAPR performance. At low and moderate work rates and flow rates below the NIOSH minimum of 170 L/min, mFF was greater than or equal to 250, which is 10 times the OSHA APF of 25 for loose-fitting facepiece PAPRs. At high work rates and flow rates below 170 L/min, mFF was not greater than or equal to 250. These results suggest that some loose-fitting facepiece PAPRs designed with a flow rate lower than the current NIOSH requirement of 170 L/min may provide respirator users with expected protection at low and moderate work rates. However, when used at high work rates, some loose-fitting facepiece PAPRs designed with lower flow rates may not provide the expected level of protection.

Ultrasound-Guided Percutaneous Dilatational Tracheostomy for Critically Ill Patients With COVID-19

Background and Objectives The global coronavirus disease 2019 (COVID-19) pandemic has had a major impact on healthcare, especially in the area of critical care due to the longer period of mechanical ventilation. Ultrasound-guided percutaneous tracheostomy (US-PDT) is considered a safe alternative method.Materials and Method Patients with severe COVID-19 hospitalized in the intensive care unit (ICU) who were on mechanical ventilation for 5 days or longer were evaluated for percutaneous dilational tracheostomy. The procedure was performed with personal protective equipment with powered air purifying respirator (PAPR) in the ICU isolated by negative pressure. Parameters such as mortality, incidence of infection to medical staff, major and minor complications were observed.Results The average time taken for US-PDT was 6.4 minutes. Five patients (27.8%) showed oxygen saturation of less than 90% due to apnea during tracheotomy, but there was no case of severe hypoxemia that required discontinuation or re-intubation. There was no COVID-19 infection of medical staff related to the procedure. A total of 9 patients (50%) died from COVID-19 pneumonia, and 1 patient (5.6%) was decannulated. There was no death due to US-PDT and no serious complications such as pneumothorax or accidental decannulation were observed.Conclusion As patients eligible for tracheostomy increased significantly due to the COVID-19 epidemic, US-PDT can be considered to be a useful technique for COVID-19 patients who require long-term mechanical ventilation. This technique can lower the risk of transmission to medical staffs who are at the forefront of being exposed to the risk of infection when an epidemic breaks out.

Determination of the model of a powered air-purifying respirator for researching its operational modes

Purpose. Justification of technical decisions when creating an experimental equipment of a powered air-purifying respirator (PAPR), development of a research system, planning and conducting an experiment, determining the structure of the object and its parameters, confirming the adequacy of the obtained simulation model of the PAPR to the control object in accordance with the conditions of the technological process. Methodology. The research was carried out on experimental equipment by means of an active experiment. It is proposed to use a sensor with an analog output and a controller for data registration to control the pressure. By varying the rotation speed of the fan, the value of the pressure in the respirator mask was determined. Structural and parametric identification and verification of the obtained model for adequacy to the control object according to the Fisher criterion were carried out on the basis of the obtained data. Findings. Based on the results of the study, it was established that the PAPR is an asymmetric object according to the "fan rotation speed - pressure in the mask" channel. The processes of pressure increase and decrease correspond in form to exponential functions and can be described by aperiodic links of the first order with different time constants. Based on the analysis of the structure of the control object, a corresponding asymmetric model was created in which aperiodic links are represented in the state space. Theprocess time constants and amplification factor of the model were determined by parameter estimation. The adequacy of the obtained simulation model to the control object was confirmed by Fisher's criterion. Originality. For the first time, a continuous transfer function of a PAPR was obtained in the form of a complex of two firstorder aperiodic links with different time constants. Practical value. A universal method of obtaining simulated models of PAPRs by using the developed experimental equipment and simulation environment of the MATLAB. The obtained simulation model of the PAPR allows to research its operating modes in order to determine the requirements for the control system and its further synthesis using various regulators.

Validation of personal protective equipment ensembles, incorporating powered air-purifying respirators protected from contamination, for the care of patients with high-consequence infectious diseases

The UK High-Consequence Infectious Diseases (HCID) Network of high-level isolation units provides care for patients with contact- or airborne-transmissible highly infectious and highly dangerous diseases. In most HCID units, the healthcare workers (HCWs) wear personal protective equipment (PPE) ensembles incorporating a powered air-purifying respirator (PAPR) for head and respiratory protection. Some PAPRs have components worn outside/over other PPE, necessitating decontamination of re-usable elements. Two alternative PAPRs, with all re-usable elements worn under PPE, were trialled in this study. To undertake scenario-based testing of PAPRs and PPE to determine usability, comfort and ability to remove contaminated PPE without personal cross-contamination. Trained healthcare volunteers (N=20) wearing PAPR/PPE ensembles were sprayed with ultraviolet fluorescent markers. They undertook exercises to mimic patient care, and subsequently, after doffing the contaminated PPE following an established protocol, any personal cross-contamination was visualized under ultraviolet light. Participants also completed a questionnaire to gauge how comfortable they found the PPE. The ensembles were tested under extreme 'worst case scenario' conditions, augmented by physical and manual dexterity tests. Participating volunteers considered the exercise to be beneficial in terms of training and PPE evaluation. Data obtained, including feedback from questionnaires and doffing buddy observations, supported evidence-based decisions on the PAPR/PPE ensemble to be adopted by the HCID Network. One cross-contamination event was recorded in the ensemble chosen; this could be attributed to doffing error, and could therefore be eliminated with further practice.

Comparison of respiratory protection during exercise tasks between different methods of wearing replaceable particulate respirators and powered air-purifying respirators.

This study evaluated the differences in respiratory protection between replaceable particulate respirators (RPRs) and powered air-purifying respirators (PAPRs) based on different wearing methods during exercise tasks. Ten participants wore RPRs and PAPRs alternately in ways comparable to those adopted by workers in actual workplaces. We measured the fit factor of the respiratory protective equipment (RPE) during exercise tasks for each wearing variation. The exercise load was set to 80W using an ergometer. The exercise tasks comprised five actions described in the Japan Industrial Standard T8150 in 2018. We compared the results with experimental data obtained at rest in our previous studies. The fit factor of RPRs during exercise was significantly lower than (p<0.001) and about half that measured at rest, indicating inadequate respiratory protection. On the other hand, the fit factor of PAPRs during exercise tasks was also significantly lower than (p<0.001) and about half that at rest, but respiratory protection was maintained. This suggests that the protection provided by PAPRs is independent of wearing method during exercise. PAPRs may thus be better than RPRs for workers who have to wear RPE inappropriately due to health problems.

Potrebna lična zaštitna oprema za pružaoce prehospitalne zdravstvene zaštite u pandemiji kovida 19 - sistematski pregled

Aims. Coronavirus Disease 2019 (COVID-19) is a highly contagious disease, and a variety of personal protective equipment (PPE) has been recommended as preventive measures for prehospital emergency personnel, which has led to considerable challenges and a great confusion for the personnel. This review aims to identify different types of PPE required in the care of COVID-19 patients in prehospital emergency system. Material and methods. This study was carried out by searching through databases including: Pubmed, Proqust, Google Scholar, and Cinahl. All articles that recommended different types of PPE against COVID-19 and infectious diseases for prehospital emergency personnel were collected in a table. Results. After carrying out the initial search in the databases, 1,009 studies were obtained and then 16 articles were selected. The findings seem to suggest using equipment including: gloves, face shields (shield/goggles), protective clothes (medical jumpsuit/scrubs), surgical masks, N-95 masks, powered air purifying respirators (PAPR), hair covers, shoe covers and washing up the hands by the emergency medical service (EMS) personnel. Discussion. The scrutiny of the relevant studies showed that each of them advised the EMS personnel to use a number of PPE. The present study highlighted the fact that there are other components of the PPE which can be useful to them. Conclusion. This study identified the most appropriate PPE needed for prehospital emergency personnel against COVID-19, and it is believed that planning for adequate access to this equipment and training on how to use them can significantly help to reduce the infection among the personnel.

Perceived Workload Using Separate (Filtering Facepiece Respirator and Face Shield) and Powered Air-Purifying Respirator and Integrated Lightweight Protective Air-Purifying Respirator: Protocol for an International Multisite Human Factors Randomized Crossover Feasibility Study.

The design of personal protective equipment (PPE) may affect well-being and clinical work. PPE as an integrated item may improve usability and increase adherence by healthcare professionals. Human factors design and safety may reduce occupational-acquired diseases. As an integrated PPE, a lightweight protective air-purifying respirator (L-PAPR) could be used during health procedures where healthcare professionals are exposed to airborne pathogens. The human factors affecting the implementation of alternative PPE such as L-PAPR have not been thoroughly studied. The population of interest is health care professionals, the intervention is the performance by PPE during tasks across the three PPE types 1.) N95 respirators and face shields, 2.)traditional powered air-purifying respirator(PAPR), and 3.) L-PAPR. The outcomes are user error, communications, safety, and end-user preferences. This study will assess whether the L-PAPR improves health care professionals' comfort in terms of perceived workload and physical and psychological burden during direct patient care when compared with the traditional PAPR or N95 and face shield. This study also aims to evaluate human factors during the comparison of the use of L-PAPR with a combination of N95 respirators plus face shields or the traditional PAPRs. This is an interventional randomized crossover quality improvement feasibility study consisting of a 3-site simulation phase with 10 participants per site and subsequent field testing in 2 sites with 30 participants at each site. The 3 types of respiratory PPE will be compared across medical tasks and while donning and doffing. We will evaluate the user's perceived workload, usability, usage errors, and heart rate. We will conduct semistructured interviews to identify barriers and enablers to implementation across each PPE type over a single continuous wear episode and observe interpersonal communications across conditions and PPE types. We expect the research may highlight communication challenges and differences in usability and convenience across PPE types along with error frequency during PPE use across PPE types, tasks, and time. The design of PPE may affect overall well-being and hinder or facilitate clinical work. Combining 2 pieces of PPE into a single integrated item may improve usability and reduce occupational-acquired diseases. The human factors affecting the implementation of an alternative PPE such as L-PAPR or PAPR have not been thoroughly studied. PRR1-10.2196/36549.

How Are You Feeling? Interpretation of Emotions through Facial Expressions of People Wearing Different Personal Protective Equipment: An Observational Study.

(1) Background: The perception of others’ emotions based on non-verbal cues, such as facial expressions, is fundamental for interpersonal communication and mutual support. Using personal protection equipment (PPE) in a work environment during the SAR-CoV-2 pandemic challenged health professionals’ ability to recognise emotions and expressions while wearing PPE. The working hypothesis of this study was that the increased limitation of facial visibility, due to the use of a personal protective device, would interfere with the perception of basic emotions in the participants. (2) Methods: Through a cross-sectional descriptive study, the present research aimed to analyse the identification of four basic emotions (happiness; sadness; fear/surprise; and disgust/anger) through three types of PPE (FFP2 respirator, protective overall and powered air-purifying respirator (PAPR)), by using 32 photographs. The study was conducted using volunteer participants who met the inclusion criteria (individuals older than 13 without cognitive limitations). Participants had to recognise the emotions of actors in photographs that were randomly displayed in an online form. (3) Results: In general, the 690 participants better recognised happiness and fear, independently of the PPE utilised. Women could better identify different emotions, along with university graduates and young and middle-aged adults. Emotional identification was at its worst when the participants wore protective overalls (5.42 ± 1.22), followed by the PAPR (5.83 ± 1.38); the best scores were obtained using the FFP2 masks (6.57 ± 1.20). Sadness was the least recognised emotion, regardless of age. (4) Conclusions: The personal protective devices interfere in the recognition of emotions, with the protective overalls having the greatest impact, and the FFP2 mask the least. The emotions that were best recognised were happiness and fear/surprise, while the least recognised emotion was sadness. Women were better at identifying emotions, as well as participants with higher education, and young and middle-aged adults.

Exploring healthcare workers’ perspectives of video feedback for training in the use of powered air purifying respirators (PAPR) at the onset of the COVID-19 pandemic

BackgroundWith the advent of COVID-19, many healthcare workers (HWs) in Australia requested access to powered air purifying respirators (PAPR) for improved respiratory protection, comfort and visibility. The urgency of the response at our hospital required rapid deployment of innovative training to ensure the safe use of PAPRs, in particular, a video-feedback training option to prepare HWs for PAPR competency.AimTo explore the feasibility, acceptability, and utility of video-feedback in PAPR training and competency assessment.MethodsSemi-structured interviews were conducted with 12 HWs, including clinicians from Intensive Care, Anaesthetics and Respiratory Medicine, at a large teaching hospital in Australia.FindingsParticipants believed that the use of video-feedback in PAPR training was feasible, acceptable and useful. They described a variety of benefits to learning and retention, from a variety of ways in which they engaged with the personal video-feedback. Participants also described the impact of reviewing personalised practice footage, compared to generic footage of an ideal performance.ConclusionBy conceptualising video-feedback using a pedagogical approach, this study contributes to knowledge around optimising methods for training HWs in PPE use, particularly when introducing a new and complex PPE device during an infectious disease outbreak.

Pneumoconiosis prevention and personal protective equipment

Inhalation of mineral dust increases the risk of pneumoconiosis which is an incurable and irreversible occupational disease. If the concentration of fibrogenic dust significantly exceeds the occupational exposure limit (OEL), the risk of pneumoconiosis becomes unacceptably high. The disease prevention involves the use of the collective prevention equipment and medical control. If these measures are insufficient, the respiratory protective devices are used. But respirators lack reliability. For example, pneumoconiosis (the initial stages of the disease) was found in a miner who had worked in the mine for only about six months. The miners cannot use respirators for a long time: they complicate communication during work and excessively impair gas exchange when breathing. The average concentration of carbon dioxide in the air inhaled from a respirator mask may exceed the maximal allowable concentration (MAC) set for the working space air by more than 2 times. The article provides a brief overview of improving respiratory protective equipment (RPE) in the United States: development of different Powered Air Purifying Respirators (PAPR); implementation of a personal dust monitor for measuring the dust concentration in real time. PAPR improve gas exchange during breathing and reduce the risk of unfiltered air leakage through gaps in facial contact areas. The effectiveness of the collective prevention equipment depends on many factors. It can be significantly increased via efficient monitoring of dust concentration in the breathing zone of a miner. Russian MAC on air dustiness create favorable conditions for the development of personal dust meters for determining dust concentration in real time. The article provides recommendations for improving dust protection of miners with regard to the international experience.The study was carried out without support. The authors declare no conflicts of interests.

Personal Protective Equipment Efficiency in Healthcare Emergencies: A Single-Center Experience.

Coronavirus disease 2019 (COVID-19) has dramatically shifted the healthcare landscape since 2020. Measures against it includes universal masking in the healthcare areas and the community, viral testing before aerosolizing procedures, and ambulatory elective surgical procedures. Some hospitals have had mandated viral testing policies even before admission to the hospital. Healthcare workers (HCWs) have been cautiously modifying all pertinent practices to avoid the transmission of the virus.Personal protective equipment (PPE), including gowns, gloves, eye protection, and properly fitted N95 respirator or powered air-purifying respirators (PAPR) while treating the suspected and confirmed COVID-19 patients were made mandatory. Similarly, we changed our aerosol-generating procedures (AGPs) protocols based on available limited data. We amended our approach to in-hospital cardiopulmonary resuscitation (basic life support (BLS)/advanced cardiovascular life support (ACLS)), given the risk of aerosol generation and transmission during the process. This article shares our experience and outcomes of PPE use in healthcare emergencies at our tertiary care academic center.

Short-term effects of the toxic component of traffic-related air pollution (TRAP) on lung function in healthy adults using a powered air purifying respirator (PAPR)

Short-term exposure to traffic-related air pollution (TRAP) are associated with reduced lung function. However, TRAP is a mixture of various gaseous pollutants and particulate matter (PM), and therefore it is unknown that which components of TRAP are responsible for the respiratory toxicity. Using a powered air-purifying respirator (PAPR), we conducted a randomized, double-blind, crossover trial in which 40 adults were exposed to TRAP for 2 h at the sidewalk of a busy road. During the exposure, the participants wore the PAPR fitted with a PM filter, a PM and volatile organic compounds (VOCs) filter, or a sham filter (no filtration, Sham mode). The participants were blinded to the type of filter in their PAPR, and experienced three exposures, once for each intervention mode in random order. We measured two lung function measures (forced expiratory volume in 1 s [FEV1] and forced vital capacity [FVC]) and an airway inflammation marker (fraction of exhaled nitric oxide [FENO]) before and immediately after each exposure, and further measured them at different time periods after exposure. We applied linear mixed effect models to estimate the effects of the interventions on the changes of lung function from baseline values after controlling for other covariates. Compared to baseline, exposing to TRAP decreased FEV1 and FVC, and increased FEV1/FVC and FENO in all three intervention modes. The mixed models showed that with the sham mode as reference, lung function and airway inflammation post exposure were significantly improved by filtering both PM and VOCs, but marginally affected by filtering only PM. In conclusion, the VOCs component of TRAP is responsible for the reduction in lung function caused by short-term exposure to TRAP. However, the result needs to be interpreted cautiously before further verified by laboratory experiment using purely isolated component(s) of TRAP.