A building must meet requirements related to energy usage and good indoor environment. The building ́s ventilation system aims to maintain optimal air quality, thermal condition, and efficient energy usage. By being able to control and adjust airflow as needed with a Variable Air Volume (VAV) system, energy usage of the ventilation system can be reduced without sacrificing indoor air quality. The VAV system operates with a variable airflow, so the accuracy of the VAV terminal at low flows is important. The study aims to verify the accuracy of three different methods for measuring airflow: iris damper, hot- wire anemometer, and volume flow hood. Data collection was carried out through measurements in a laboratory environment. The collected data were managed in the Excel spreadsheet program. The three methods were tested on a prototype consisting of a supply airline and an exhaust airline, each equipped with a VAV unit that varied the airflow through a potentiometer, allowing different airflow values to be obtained for the experiment. The results of the iris damper method were chosen as reference for the other methods due to its ability to predict results using manufacturer tables, which provide useful information about airflow values when varying pressure drop and the iris damper loss k-factor. In this way, set points were stablished for all tests. Two experiments were conducted with different set points. In retrospect it is acknowledged that an air flow meter of higher accuracy had been needed to ascertain the results of the study. That said, the attained results indicate the following: In the experiments, measurements were taken for 12 different airflow values, ranging from 200 l/s to 20 l/s. The test results showed that the most inaccurate method was the volume flow hood, with an average error ranging from ±19% to ±49%, followed by the hot wire anemometer, which had a measurement error between ±15% to ±18%. The high inaccuracy of the volume flow hood was due to a lack of instrument recalibration, resulting in highly inaccurate measurements. All methods showed lower uncertainty between 20 l/s and 50 l/s. Finally, it was verified that the iris damper method improved its average reading error by increasing the pressure drop across the damper and reducing its loss k-factor, achieving the lowest error of the entire experiment at ±12%.

京都大学 / 新制・課程博士 / 博士(医学) / 甲第25193号 / 医博第5079号 / 新制||医||1072(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 山本 洋介, 教授 中山 健夫, 教授 江木 盛時 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DFAM

Purpose To determine the relationship of chemosensory screening and nasal airflow tests among the same set of participants, and to determine other factors that are related to the outcomes of these tests. Methods Participants had no chemosensory complaints. Structured medical history was taken. Participants underwent 5 screening tests: q-sticks (orthonasal olfaction), q-powders (retronasal olfaction), trigeminal lateralization test, taste sprays, and peak nasal inspiratory flow (PNIF). Ratings of smell/taste ability and nasal airflow were obtained using visual analogue scales (VAS). Composite sinusitis symptoms and significance of olfaction questionnaire scores were also determined. Results Four hundred participants were included in the study, 156 men, 244 women; aged 18–82 years (mean: 46). The q-powders and taste spray scores were weakly positively correlated with all the other chemosensory tests and PNIF. However, chemosensory test scores were not correlated with VAS, composite sinusitis symptoms, and significance of olfaction questionnaire scores. Various tests showed significant decrease starting at specific ages (in years, PNIF and trigeminal lateralization: 40, q-powders: 60, and q-sticks: 70). Conclusion Chemosensory screening tests and self-rated chemosensory function showed no correlation in participants without chemosensory complaints. In addition, gustatory function appeared to be correlated with olfactory and trigeminal function but also with nasal airflow, and nasal airflow was related not only to olfactory but also to trigeminal and taste function. Over all, the results suggest that chemosensory functions (orthonasal olfactory, trigeminal, retronasal olfactory, gustatory) and nasal airflow are correlated with each other, which we propose may be possibly mediated, at least in part, through central nervous system interactions.

It is possible to simulate an airflow by additives to shoot images and records of such flowing. Additives can be in the form of particles or continuous filaments. A computer evaluation of such data differs depending on the kind of visualization method. This thesis deals with a number of different approaches to determine the airjet shape and airflow velocity in airflow images and records. Exact procedures area sed for these purposes as well as neural networks and genetic algorithms.

Doctor of Philosophy / Department of Mechanical and Nuclear Engineering / M. H. Hosni / B. W. Jones / This dissertation focuses on airflow distribution in the longitudinal direction of a wide-body mockup aircraft cabin, turbulence energy and dissipation rates, and the effect of thermal plumes, generated by passengers, on airflow distribution within the cabin. The mockup cabin utilized for this study mimics a Boeing 767 passenger cabin and includes 11 rows in the longitudinal direction with each row consisting of seven seats. Each seat is occupied by an inflatable manikin which is instrumented with a 10 meters long wire heater generating approximately 100 Watts of distributed sensible heat, representing heat load from a sedentary human being. In order to investigate the fluid dynamics characteristics of the airflow within the cabin, different experimental techniques were implemented. Smoke visualization was used to qualitatively visualize the general airflow pattern inside the cabin. A tracer gas composed mainly of carbon dioxide was used to track the airflow distribution inside the cabin. The tracer gas was released in several locations and then sampled at various locations throughout the mockup cabin. The release and sampling of the tracer gas allowed tracing the airflow inside the cabin using non dispersive infrared sensors. Combining results from different release-sampling scenarios gave better understanding of the chaotic and three-dimensional nature of the airflow behavior inside the cabin. Air speed and turbulence parameters were evaluated using omni-directional probes. Finally, the effect of the heat generated by the thermal manikins on the airflow behavior was investigated. The results from the airflow visualization and the tracer gas were complementary and showed that there were multiple air circulations along the length of the cabin. The dimension of the circulations were controlled by the minimum physical distance inside the cabin. The identified-isotropic turbulence were spread over the full width of the cabin in the front and middle sections of the cabin, whereas, multiple-smaller circulations were identified in the rear section. Cabin sections identified with high speed fluctuations were associated with higher turbulence kinetic energy levels and lower local dissipation rates. These sections served as driving forces to create the circulations identified in the tracer gas experiments. Furthermore, the heat generated by the thermal manikins was shown to significantly impact the behavior of the gaseous flow inside the cabin, the turbulence parameters, and speed fluctuations. Detailed uncertainty analysis was conducted to estimate the uncertainty limits for the measurements taken. The uncertainty estimates obtained for the tracer gas results ranged from ±14% for the test cases with the heated manikins to ±17% with the corresponding unheated manikins cases. The data uncertainty limits for the turbulence parameters were of higher levels due to limitations associated with the omni-directional probes used to measure the speed. With flow repeatability phenomena in same locations inside the mockup cabin during different days reaching up to ±10%, the uncertainty estimates were considered acceptable for these chaotic and highly random airflow conditions within the cabin.

Doctor of Philosophy / Department of Mechanical and Nuclear Engineering / M.H. Hosni / Z.C. Zheng / In order to study the capability of computational methods in investigating the mechanisms associated with disease and contaminants transmission in aircraft cabins, the Computational Fluid Dynamics (CFD) models are used for the simulation of turbulent airflow, tracer gas diffusion, and particle dispersion in a generic aircraft cabin mockup. The CFD models are validated through comparisons of the CFD predictions with the corresponding experimental measurements. It is found that using Large Eddy Simulation (LES) with the Werner-Wengle wall function, one can predict unsteady airflow velocity field with relatively high accuracy. However in the middle region of the cabin mockup, where the recirculation of airflow takes place, the accuracy is not as good as that in other locations. By examining different k-ε models, the current study recommends the use of the RNG k-ε model with the non-equilibrium wall function as a Reynolds Averaged Navier Stokes (RANS) model for predicting the steady-state airflow velocity data. It is also found that changing the cabin air-inlet nozzle height has a significant effect on the flow behavior in the middle and upper part of the cabin, while the flow pattern in the lower part is not affected as much. Through the use of LES and species transport model in simulating tracer gas diffusion, very good agreement between predicted and measured tracer gas concentration data is observed for some monitoring locations, but the agreement level is not uniform for all the sampling point locations. The reasons for the deviations between predictions and measurements for those locations are discussed. The Lagrange-Euler approach is invoked in the particle dispersion simulations. In this approach, the equation of motion for the discrete phase is coupled with the continuous phase governing equations through the calculation of drag and buoyancy forces acting on particles. The continuous phase flow is turbulent and RANS is employed in order to calculate the continuous phase velocity field. A complete study on grid dependence for RANS simulation is performed through a controllable regional mesh refinement scheme. The grid dependence study shows that using unstructured grid with tetrahedral and hybrid elements in the refinement region are more efficient than using structured grid with hexahedral elements. The effect of turbulence on the particle dispersion is taken into account by using a stochastic tracking method (Discrete Random Walk model). One of the significant features of this study is the investigation of the effect of the number of tries on the accuracy of particle concentration predictions when Discrete Random Walk is used to model turbulent distribution of particles. Subsequently, the optimum number of tries to obtain the most accurate predictions is determined. In accordance with the corresponding experimental data, the effect of particle size on particle distribution is also studied and discussed through the simulation of two different sizes of mono-disperse particles in the cabin with straight injection tube, i.e., 3µm and 10µm. Due to the low particle loading, neglecting the effect of particles motion on the continuous phase flow-field seems to be a reasonable, simplifying assumption in running the simulations. However, this assumption is verified through the comparison of the results from 1-way and 2-way coupling simulations. Eventually through the simulations for the particle injection using the cone diffuser, the effects of cabin pressure gradient as well as the particle density on particles dispersion behavior are studied and discussed. In the last part of this dissertation, the turbulent airflow in a full-scale Boeing 767 aircraft cabin mockup with eleven rows of seats and manikins is simulated using steady RANS method. The results of this simulation cannot only be used to study the airflow pattern, but also can be used as the initial condition for running the tracer gas diffusion and particle dispersion simulations in this cabin mockup.

Byggnadssektorn står för 36 % av utsläppen av CO2 till miljön och ungefär 40 % av världens totala energianvändning. Byggnader med större energieffektivitet och hållbarhet har potential att minska: den slutliga energianvändningen, utsläpp av växthusgaser, materialutvinning och användning av dricksvatten. Det är därför viktigt att utföra åtgärder för befintliga och blivande byggnader samt undersöka alternativa byggnadssätt och material som  kan innebära en minskad energianvändning och en begränsning av miljöpåverkan.   Syftet med denna rapport är att undersöka värmeflödesegenskaperna för sexton olika isoleringsmaterial, av vilka fjorton stycken är mindre vanliga i byggnadssammanhang, samt att undersöka hur luftflödet för ett väggparti förbättras av att den lerklinas på en respektive två sidor. Experimenten för värmeflöde utfördes med hjälp av Hotbox-Coldbox metoden. Boxen i studien hade en kammare som kyldes ner och därmed representerade utetemperatur medan den varma temperaturen i lokalen, som boxen stod i, fick representera ett varmt inneklimat. Väggarna undersöktes med hjälp av värmeflödesmätare och temperaturgivare som placerades på väggytorna. Temperaturgivare placerades även upphängd inuti och utanför boxen för att åskådliggöra luftens temperatur inuti boxen och i lokalen.   Samma box användes för lufttäthetsprovningen, då hopmonterad med en fläkt som drog ut luften med ett undertryck ur boxen och skapade en tryckskillnad som innebar att luftflödet genom väggpartiet kunde beräknas med hjälp av en strypfläns.   Den empiriska studiens resultat för värmeflödesmätningen visar och jämför R-värden, lambdavärden (λ) och U-värden för konventionella och alternativa material. De bästa värmeflödesegenskaperna fick cellplasten, följd av mjuk träfiberskiva och klippt halm. Det isoleringsmaterial som presterade sämst i mätningarna var lerhalmen, men då dess dåliga värden troligen härrör från ett konstruktionsfel bör det vara torv som egentligen har sämst värmeisolerande egenskaper.   Resultaten från luftflödesmätningen visar att en vägg med lerklining på båda sidorna av konstruktionen nästan är 2,5 gånger mer lufttät än en vägg med enbart en yta lerklinad och 3,3 gånger bättre än den vägg som inte alls lerklinats.   De slutsatser som kunde dras av arbetet är att en del av de alternativa materialen (klippt halm och mjuk träfiberskiva) har goda möjligheter att agera som substitut för mer konventionella material under förutsättning att det utförs ytterligare forskning av dem. Det som skulle behöva undersökas närmre är, till exempel, deras fuktegenskaper eftersom naturliga material har en högre fuktkänslighet. Vidare bedöms det att lufttätheten förbättras markant av både en- och tvåsidig lerklining, men att den tvåsidiga är att föredra. / The building sector produces 36 % of the CO2 emissions to the environment and claims approximately 40 % of the worlds total energy usage. Buildings have a potential of reducing the net usage of energy, emissions of greenhouse gases, material extraction and usage of drinking water if they were to have a bigger energy efficiency and be more sustainably built. This is why it is of importance to intervene and review alternative ways of constructing buildings and different materials which can result in a reduced energy usage and a limited environmental footprint.   The objectives of this report is to examine the properties of heat flow through sixteen different materials of insulation, fourteen of these are alternative, less conventional. It also investigates how the airflow of a wall will improve by using a technique of wattle and daub on its facade.   The heat flow experiments were conducted with the use of the Hotbox-Coldbox method. The box in the tests had one chamber, which were cooled and thereby representing an outer temperature and the warm temperature in the room surrounding the box represented an inner climate. The walls were studied using heat flow measurers (Hukseflux) and temperature sensors on the inner and outer surfaces of the wall. Temperature sensors were also placed inside and outside the box in order to show the temperature of the air inside the box and in the surrounding room. The same box were used for the investigation of airflow, but then rigged with a fan which blew out the air inside the box. The difference in pressure that was created meant that the airflow through the wall could be calculated by using an orifice plate.   The results of the empirical study visualizes and compares R - values, lambda values (λ) and U - values for conventional and alternative materials. The expanded polystyrene insulation had the best values, followed by the soft board of wood grain and the sheared straw. The material performed the poorest was the straw which was mixed with clay. Though, because its values probably were due to faulty construction of the insulation, the poorest achievement should belong to the peat insulation. The airflow measurement showed a wall with two sides prepared with wattle and daub performed almost 2.5 times better than a wall with only one side prepared and 3.3 times better than a wall with no surface treatment.   Conclusions can be made out of the study that some of the alternative insulation materials (sheared straw and soft board of wood grain) has potential for acting as a substitute for conventional materials, though further research is required. The amount of airflow is deemed to be improved by wattle and daub although it is best if it is applicated on two sides.

Introdução: A respiração oronasal pode impactar adversamente em pacientes com apneia obstrutiva do sono (AOS) pelo aumento da colapsabilidade da via aérea piorando as apneias ou por influenciar os desfechos de tratamento com a pressão positiva continua de vias aéreas (CPAP). Embora os autorrelatos de respiração oronasal sejam comumente utilizados como uma evidência para prescrição da CPAP oronasal, a associação entre o autorrelato e a mensuração objetiva da via preferencial de respiração ainda é desconhecida. Nós hipotetizamos que a respiração oronasal objetivamente mensurada seja mais comum em pacientes com AOS do que em controles, mas que não esteja associada com o autorrelato de respiração oronasal. Os objetivos do presente estudo foram, portanto, determinar: (1) a via preferencial de respiração em controles e pacientes com AOS na vigília e no sono, (2) a concordância entre a via preferencial de respiração mensurada objetivamente e a via preferencial de respiração autorrelatada, e (3) a associação entre a via preferencial de respiração mensurada objetivamente e os sintomas nasais e fatores em pacientes com AOS. Casuística e Método: Foram incluídos 26 indivíduos não tabagistas recrutados na FMUSP (funcionários) e no Ambulatório de Sono do InCor-HCFMUSP (indivíduos com suspeita de AOS). Para o diagnóstico de AOS os indivíduos foram submetidos a uma polissonografia (PSG). A AOS foi definida como índice de apneia-hipopneia (IAH) >= 15 eventos/hora e determinou a alocação dos indivíduos em dois grupos: grupo controle [idade: 40±10 anos, 4 (44%) homens, índice de massa corpórea (IMC): 25±5 kg/m2, IAH: 5±4 eventos/hora] e grupo AOS (idade: 52±14 anos, 10 (59%) homens, IMC: 31±5 kg/m2, IAH: 56 ± 21 eventos/hora). Para avaliar a via preferencial de respiração (nasal ou oronasal) os indivíduos foram submetidos a uma segunda PSG com uso de uma máscara com 2 compartimentos selados (nasal e oral) e conectados a pneumotacógrafos independentes. A via de respiração preferencial foi determinada durante a vígilia que antecedeu o início de sono e durante o sono. Avaliamos dados clínicos e de função pulmonar. Os indivíduos responderam a questionários sobre a percepção da sua via preferencial de respiração, os sintomas nasais (SNOT-20), a sonolência diurna excessiva (Epworth) e a qualidade do sono (Pittsburgh). Resultados: O grupo controle e AOS foram similares no sexo, co-morbidades e uso de medicamentos. Pacientes com AOS eram mais velhos, tinham maior IMC, pressão arterial sistêmica e circunferência do pescoço. A via preferencial de respiração foi similar na vigília e sono. Observamos que os respiradores oronasais foram mais frequentes nos pacientes com AOS se comparados aos controles (65-71% e 0-22%, respectivamente, p < 0,001). Os controles e pacientes com AOS autorrelataram respiração oronasal em 22% e 59% dos casos, respectivamente (p = 0,110). Entretanto, encontramos pobre concordância entre o autorrelato da via de respiração e a via de respiração identificada no grupo controle (Kappa = 0,36) e nenhum concordância nos pacientes com AOS (Kappa = -0,02). Não houve associação entre os sintomas nasais e a respiração oronasal quando considerados todos os indivíduos do estudo (p = ,267). A respiração oronasal foi associada ao aumento do IAH (r = 0,409 e p = 0,038), aumento da idade (r = 0,597 e p = 0,001) e aumento da circunferência do pescoço (r = 0,464 e p = 0,017). Além disso, mudanças na via de respiração após apneias obstrutivas foram incomuns. Conclusões: Em contraste com os controles, os pacientes com AOS sãos frequentemente respiradores oronasais. Contudo, a auto-percepção da via de respiração e de sintomas nasais não prediz medidas objetivas da via preferencial de respiração. Além disso, a respiração oronasal é associada à gravidade da AOS, ao aumento da idade e da circunferência do pescoço / Background: Oronasal breathing may adversely impact obstructive sleep apnea (OSA) patients either by increasing upper airway collapsibility or by influencing CPAP treatment outcomes. Although self-reported oronasal breathing is commonly used as evidence for oronasal CPAP prescription, the association between self-reported and objectively measured preferential breathing route is unknown. We hypothesized that objectively measured oronasal breathing is more common in OSA patients than in controls but is not associated with self-reported breathing route. The aims of this study were, therefore, to determine (1) the preferential breathing route in controls and OSA patients, (2) the agreements between objective analysis of breathing route and self-reports, and (3) the associations between preferential breathing route objectively measure and nasal symptoms and factors in OSA patients. Methods: We included 26 non-smokers enrolled at FMUSP (employees) and Sleep Laboratory at InCor-HCFMUSP (individuals with suspected AOS). For the diagnosis of OSA, the subjects were submitted a full polysomnography (PSG). OSA was defined as apnea-hypopnea index (AHI) >= 15 events/hour and determined the allocation of individuals in two groups: Control group [age: 40 ± 10 years, 4 (44%) men, body mass index (BMI): 25±5 kg/m2, AHI: 5 ± 4 events / hour] and OSA group (age: 52 ± 14 years, 10 (59%) men, BMI: 31±5 kg/m2, mean AHI: 56 ± 21 events / hour). To evaluate the preferential breathing route (nasal or oronasal) the subjects underwent a second overnight PSG with oronasal mask with 2 sealed compartments attached to independent pneumotacographs. The preferential breathing route was determined during wakefulness before sleep and during sleep. We evaluated clinical data and lung function. Subjects answered questionnaires about perceived preferential breathing route, nasal symptoms questionnaires (SNOT-20), excessive daytime sleepiness (Epworth) and sleep quality (Pittsburgh). Results: Controls and OSA patients were similar in sex, co-morbidities and use of medications. OSA patients were older, had higher BMI and blood pressure as larger neck circumference. Breathing pattern awake and asleep was similar. Compare to controls, oronasal breathers was more frequent in OSA patients (0-22% and 65-71%, respectively, p < 0.001). Controls and OSA patients self-reported oronasal breathing in 22% and 59% of cases, respectively (p = 0.110). There were poor agreements between self-reports and objective analysis in controls (Kappa = 0.36) and no agreement in OSA patients (Kappa = -0.02). No associations were found between nasal symptoms and oronasal breathing when all subjects were considered (p = 0.267). Oronasal breathing was associated with OSA severity (r = 0.409 and p = 0.038), increasing age (r = 0.597 and p = 0.001) and higher neck circumference (r = 0.464 and p = 0.017). Additionally, the changes of breathing route were uncommon during obstructive apneas. Conclusions: In contrast to controls, OSA patients are preferentially oronasal breathers. However, self-perception does not predict objectively measured preferential breathing route. Oronasal breathing is associated with OSA severity, increasing age and higher neck circumference

Este trabalho apresenta um estudo sobre o escoamento de ar em dutos com múltiplas saídas que são identificados como caixas sopradoras, quando instalados em máquinas desaguadoras de celulose. Estas caixas auxiliam o processo de secagem conduzindo ar aquecido até um conjunto de orifícios que produzem jatos que são impingidos sobre as folhas de celulose fabricadas. É realizada revisão bibliográfica abordando processos e equipamentos de secagem, com foco no escoamento de ar, métodos para solução numérica de escoamentos, seus modelos e parâmetros, e abordagem semi-empírica para fluxos de ar na saída de dutos. O escoamento do ar no interior da caixa sopradora e nos jatos de saída são estudados através de simulação numérica, e de modelo semi-empírico. São propostas duas alternativas de geometria para estes dutos de modo que se garanta a maior uniformidade possível na vazão e na velocidade média do ar que saí através dos orifícios Na primeira alternativa considera-se que a seção transversal da caixa sopradora se mantém constante. Na segunda se considera que a seção transversal seja reduzida de modo uniforme ao longo da caixa sopradora. Um estudo experimental sobre o comportamento do escoamento de ar para caixas sopradoras em escala reduzida apresenta resultados que possibilitam validar um conjunto de valores numéricos obtidos na simulação e também estabelecer características para o escoamento de modo a atender o processo de secagem. Para cada alternativa são adotadas duas condições de vazão de ar. Os resultados obtidos pela da simulação numérica e modelagem semi-empírica validam um perfil geométrico adequado para que a caixa sopradora produza um conjunto de jatos nas suas saídas com valores de velocidade média. Um dos principais resultados foi obtido para a caixa com 275 orificios, na qual as velocidades médias estiveram dentro do intervalo de 32,5 m/s e 33,1 m/s, que representou um ótimo resultado em termos de balanceamento e uniformidade das vazões de ar. / This study presents an analysis about airflow in ducts with multiple outlets that are identified as blow boxes, when installed in pulp dewatering machines. These boxes work in the drying process leading heated air to a set of nozzles that produce air jets that are impinged against the pulp sheet. It is performed literature review about drying processes and equipment, with a focus on air flow, methods for numerical solution of airflows, their models and parameters, and semi-empirical approach about airflow at the outlets of the duct. The airflow inside the blow box and the output jets are studied by numerical simulation, and semi-empirical model. It is proposed two alternative geometries for these ducts in order to guarantee the greatest possible uniformity in flow rate, and in the average velocity of air jets. In the first alternative is considered that the cross section of the blow box remains constant. In the second one it is considered that the cross section is reduced uniformly along the blow box. An experimental study about the behavior of the airflow in blow boxes, using scaled models, presents results that can validate a set of numerical values obtained in the simulation and also establish characteristics for the drying process. For each alternative two conditions of airflow are adopted. The results obtained through numerical simulation and semi-empirical modeling validates an appropriate geometrical profile for the blow box in order to set the values of average speed within the range required by the drying process. One of the principal results, obtained for the case of boxes with 275 holes, was the average speed within the range of 32,5 m/s and 33,1 m/s, this range represents a great result in tterms of balance and uniformity of air flow.

Introdução: A respiração oronasal pode impactar adversamente em pacientes com apneia obstrutiva do sono (AOS) pelo aumento da colapsabilidade da via aérea piorando as apneias ou por influenciar os desfechos de tratamento com a pressão positiva continua de vias aéreas (CPAP). Embora os autorrelatos de respiração oronasal sejam comumente utilizados como uma evidência para prescrição da CPAP oronasal, a associação entre o autorrelato e a mensuração objetiva da via preferencial de respiração ainda é desconhecida. Nós hipotetizamos que a respiração oronasal objetivamente mensurada seja mais comum em pacientes com AOS do que em controles, mas que não esteja associada com o autorrelato de respiração oronasal. Os objetivos do presente estudo foram, portanto, determinar: (1) a via preferencial de respiração em controles e pacientes com AOS na vigília e no sono, (2) a concordância entre a via preferencial de respiração mensurada objetivamente e a via preferencial de respiração autorrelatada, e (3) a associação entre a via preferencial de respiração mensurada objetivamente e os sintomas nasais e fatores em pacientes com AOS. Casuística e Método: Foram incluídos 26 indivíduos não tabagistas recrutados na FMUSP (funcionários) e no Ambulatório de Sono do InCor-HCFMUSP (indivíduos com suspeita de AOS). Para o diagnóstico de AOS os indivíduos foram submetidos a uma polissonografia (PSG). A AOS foi definida como índice de apneia-hipopneia (IAH) >= 15 eventos/hora e determinou a alocação dos indivíduos em dois grupos: grupo controle [idade: 40±10 anos, 4 (44%) homens, índice de massa corpórea (IMC): 25±5 kg/m2, IAH: 5±4 eventos/hora] e grupo AOS (idade: 52±14 anos, 10 (59%) homens, IMC: 31±5 kg/m2, IAH: 56 ± 21 eventos/hora). Para avaliar a via preferencial de respiração (nasal ou oronasal) os indivíduos foram submetidos a uma segunda PSG com uso de uma máscara com 2 compartimentos selados (nasal e oral) e conectados a pneumotacógrafos independentes. A via de respiração preferencial foi determinada durante a vígilia que antecedeu o início de sono e durante o sono. Avaliamos dados clínicos e de função pulmonar. Os indivíduos responderam a questionários sobre a percepção da sua via preferencial de respiração, os sintomas nasais (SNOT-20), a sonolência diurna excessiva (Epworth) e a qualidade do sono (Pittsburgh). Resultados: O grupo controle e AOS foram similares no sexo, co-morbidades e uso de medicamentos. Pacientes com AOS eram mais velhos, tinham maior IMC, pressão arterial sistêmica e circunferência do pescoço. A via preferencial de respiração foi similar na vigília e sono. Observamos que os respiradores oronasais foram mais frequentes nos pacientes com AOS se comparados aos controles (65-71% e 0-22%, respectivamente, p < 0,001). Os controles e pacientes com AOS autorrelataram respiração oronasal em 22% e 59% dos casos, respectivamente (p = 0,110). Entretanto, encontramos pobre concordância entre o autorrelato da via de respiração e a via de respiração identificada no grupo controle (Kappa = 0,36) e nenhum concordância nos pacientes com AOS (Kappa = -0,02). Não houve associação entre os sintomas nasais e a respiração oronasal quando considerados todos os indivíduos do estudo (p = ,267). A respiração oronasal foi associada ao aumento do IAH (r = 0,409 e p = 0,038), aumento da idade (r = 0,597 e p = 0,001) e aumento da circunferência do pescoço (r = 0,464 e p = 0,017). Além disso, mudanças na via de respiração após apneias obstrutivas foram incomuns. Conclusões: Em contraste com os controles, os pacientes com AOS sãos frequentemente respiradores oronasais. Contudo, a auto-percepção da via de respiração e de sintomas nasais não prediz medidas objetivas da via preferencial de respiração. Além disso, a respiração oronasal é associada à gravidade da AOS, ao aumento da idade e da circunferência do pescoço / Background: Oronasal breathing may adversely impact obstructive sleep apnea (OSA) patients either by increasing upper airway collapsibility or by influencing CPAP treatment outcomes. Although self-reported oronasal breathing is commonly used as evidence for oronasal CPAP prescription, the association between self-reported and objectively measured preferential breathing route is unknown. We hypothesized that objectively measured oronasal breathing is more common in OSA patients than in controls but is not associated with self-reported breathing route. The aims of this study were, therefore, to determine (1) the preferential breathing route in controls and OSA patients, (2) the agreements between objective analysis of breathing route and self-reports, and (3) the associations between preferential breathing route objectively measure and nasal symptoms and factors in OSA patients. Methods: We included 26 non-smokers enrolled at FMUSP (employees) and Sleep Laboratory at InCor-HCFMUSP (individuals with suspected AOS). For the diagnosis of OSA, the subjects were submitted a full polysomnography (PSG). OSA was defined as apnea-hypopnea index (AHI) >= 15 events/hour and determined the allocation of individuals in two groups: Control group [age: 40 ± 10 years, 4 (44%) men, body mass index (BMI): 25±5 kg/m2, AHI: 5 ± 4 events / hour] and OSA group (age: 52 ± 14 years, 10 (59%) men, BMI: 31±5 kg/m2, mean AHI: 56 ± 21 events / hour). To evaluate the preferential breathing route (nasal or oronasal) the subjects underwent a second overnight PSG with oronasal mask with 2 sealed compartments attached to independent pneumotacographs. The preferential breathing route was determined during wakefulness before sleep and during sleep. We evaluated clinical data and lung function. Subjects answered questionnaires about perceived preferential breathing route, nasal symptoms questionnaires (SNOT-20), excessive daytime sleepiness (Epworth) and sleep quality (Pittsburgh). Results: Controls and OSA patients were similar in sex, co-morbidities and use of medications. OSA patients were older, had higher BMI and blood pressure as larger neck circumference. Breathing pattern awake and asleep was similar. Compare to controls, oronasal breathers was more frequent in OSA patients (0-22% and 65-71%, respectively, p < 0.001). Controls and OSA patients self-reported oronasal breathing in 22% and 59% of cases, respectively (p = 0.110). There were poor agreements between self-reports and objective analysis in controls (Kappa = 0.36) and no agreement in OSA patients (Kappa = -0.02). No associations were found between nasal symptoms and oronasal breathing when all subjects were considered (p = 0.267). Oronasal breathing was associated with OSA severity (r = 0.409 and p = 0.038), increasing age (r = 0.597 and p = 0.001) and higher neck circumference (r = 0.464 and p = 0.017). Additionally, the changes of breathing route were uncommon during obstructive apneas. Conclusions: In contrast to controls, OSA patients are preferentially oronasal breathers. However, self-perception does not predict objectively measured preferential breathing route. Oronasal breathing is associated with OSA severity, increasing age and higher neck circumference