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Toxic and Asphyxiating Hazards in Confined Spaces
Published in Neil McManus, Safety and Health in Confined Spaces, 2018
Mouth breathing bypasses the nose and its air conditioning structures. Resistance to airflow through the mouth is about half that of the nose. During quiet breathing, the nasal passages contribute nearly half the total resistance to flow in the respiratory system (Bouhuys 1974).
Airflow design and source control strategies for reducing airborne contaminant exposure in passenger aircraft cabins during the climb leg
Published in Science and Technology for the Built Environment, 2020
Hossam A. Elmaghraby, Yi Wai Chiang, Amir Abbas Aliabadi
Changing the cough to continuous mouth breathing (exhalation) led to an altered contaminant dispersion behavior in the cabin. For the steady level flight leg, the concentration of the contaminant in the cabin was usually higher than that during the climb leg. This was attributed to the well-mixed cabin condition created throughout the steady flight leg. As a result, the contaminant concentration increased substantially everywhere in the cabin as opposed to the lower concentrations noticed during the climb leg due to the absence of enough contaminant mixing in the cabin air. The passenger exposure to the contaminant released from the continuous exhalation in the cabin between the climb and steady flight legs was estimated at seats A7 and C7 to be 0.7:1 and 0.9:1, respectively.
“The Action Level®”
Published in Journal of Occupational and Environmental Hygiene, 2023
3. Which of the following best describes particle reduction from greatest to least? LVS airflow with background ventilation > manikin breathing zone re: background aerosol > mouth breathing and coughing simulationsManikin breathing zone re: background aerosol > mouth breathing and coughing simulations > LVS airflow with background ventilationMouth breathing and coughing simulations > manikin breathing zone re: background aerosol > LVS airflow with background ventilation
Acute responses to sprint-interval and continuous exercise in adults with and without exercise-induced bronchoconstriction
Published in Journal of Sports Sciences, 2019
Joshua Good, Eric Viana, Kirsten A Burgomaster, Shilpa Dogra
Having participants breathe through a mouthpiece, thus forcing mouth breathing, may be a limitation. Previous research has shown that mouth breathing may trigger a greater EIBC response compared to nasal breathing (Shturman-Ellstein, Zeballos, Buckley, & Souhrada, 1978). Participants in the current study therefore may have been more likely to experience EIBC during or following exercise; however, during intense exercise, mouth breathing is generally the dominant breathing strategy, so the impact was likely minimal. Secondly, the current study may have been underpowered to detect differences in secondary outcomes, such as sex-based differences in the response. Previously, sex-differences have been observed for the prevalence of expiratory flow limitation, work of breathing, and bronchoconstriction in women during exercise (Guenette, Witt, McKenzie, Road, & Sheel, 2007; Harms, 2006). Thirdly, the results are also limited to young adults who are currently active, and to adults with mild EIBC, therefore future research will also need to study the response among adults of different ages, fitness levels, and asthma severity levels. Fourthly, the EVH test used to confirm EIBC may be overly sensitive and therefore participants with mild EIBC may have been included (Hull, Ansley, Price, Dickinson, & Bonini, 2016). This could explain why some participants did not experience EIBC following SIE or CE and may also explain why nine individuals with no history of asthma had a positive response to the EVH. Fifthly, it is possible that some participants may have used a pacing strategy and may not have completed each sprint with an “all out” effort. However, PPOSIE did decrease across sprints. Finally, conclusions cannot be generalized to less vigorous CE protocols as the CE protocol used in the present study was high.