This project is based on measurements of the parameter relative humidity, RH (%), in two buildings: one with natural ventilation and one with mechanical ventilation. Both buildings are located in central Sweden, which...This project is based on measurements of the parameter relative humidity, RH (%), in two buildings: one with natural ventilation and one with mechanical ventilation. Both buildings are located in central Sweden, which constitutes a representative climate zone with respect to Swedish conditions. An important factor for the indoor environment, which affects human health and well-being, is the level of the relative humidity, RH (%). Research studies show that the healthiest level should be in the range of 40% - 60%. Surveys have revealed that about 70% of the employees at Swedish offices, schools and kindergartens experience that the air is too dry during the winter season. Previous studies show that the level of relative humidity in the indoor environment influences the prevalence of respiratory infections and allergies. The purpose of this study is to investigate how the relative humidity differ between the two buildings, and if this may be a cause of the health problems that users are affected by. During many years, users have complained about the environment in the building with mechanical ventilation and that they suffer from health problems. The method used in the study is air measurements of the two parameters, relative humidity and air temperature in the two buildings using data loggers. The indoor environment is affected by the outdoor climate and therefore instruments are placed outdoors to record seasonal variations. The measurements were carried out during the period October 2014 to September 2015 to include all of Sweden’s four seasons with completely different climatic conditions. The results of this study show that the relative humidity in the mechanically ventilated building is consistently significantly lower than in the building with natural ventilation whatever the time of year and temperature indoors. This study shows that mechanical ventilation in buildings affects the indoor environment negatively with respect to human health during most time of the year and this fact must be taken into consideration for the existing as well as the planning of new ventilation systems.展开更多
Poor indoor air quality is a large problem in Swedish schools, since the health of occupants may be affected. The building itself is often in focus and other building-related problems may be neglected. The hypothesis ...Poor indoor air quality is a large problem in Swedish schools, since the health of occupants may be affected. The building itself is often in focus and other building-related problems may be neglected. The hypothesis of this study is that factors other than the building itself have decisive influence on indoor environment. An assessment of these nonspecific building-related reasons for bad indoor environment has been made in the present work using surveys combined with particle measurements and comfort measurements (air humidity and air temperature). People are experiencing poor indoor air quality, the air is too dry and the temperature is uneven and uncomfortable indoors in the winter. It is important to highlight the problem of indoor environments with high particulate emissions especially in the range from 5.0 microns and larger since they are conveyers of allergens and bacteria, combined with dry air. An interesting observation regarding the ventilation system is that mechanical systems are tending to generate drier indoor air than the natural ventilation system. Results show that it is possible to decrease emissions through eliminating activity-related sources of airborne contaminants and better the comfort indoors with relatively simple measures.展开更多
An important factor for comfort ratio in the indoor environment and affecting human health and well-being is the relative humidity. Studies have shown that about 70% of the staff at Swedish offices, schools and kinder...An important factor for comfort ratio in the indoor environment and affecting human health and well-being is the relative humidity. Studies have shown that about 70% of the staff at Swedish offices, schools and kindergartens experiences that the air is too dry during the winter season. Studies show that the relative humidity in indoor environments influences the incidence of respiratory infections and allergies. Important factors for the air environment indoors is to limit the number of airborne particles, since these are conveyors of both bacteria and viruses, and to keep the humidity at a level above 40% and below 70%, making the survival of viruses and bacteria minimized. Measurement results show that there is significant difference in the relative humidity during the winter season between the mechanically ventilated buildings with relative humidity levels below 10% than in buildings with natural ventilation. An important issue is how human health is affected by during longer periods and during much of the day live in environments with low relative humidity. Several researchers have noted that the incidence of respiratory infections increase during the winter when people are exposed to long periods of low humidity indoors. This means that the consequences of low humidity in the indoor environment should be considered and evaluated in a completely different way than is done today.展开更多
文摘This project is based on measurements of the parameter relative humidity, RH (%), in two buildings: one with natural ventilation and one with mechanical ventilation. Both buildings are located in central Sweden, which constitutes a representative climate zone with respect to Swedish conditions. An important factor for the indoor environment, which affects human health and well-being, is the level of the relative humidity, RH (%). Research studies show that the healthiest level should be in the range of 40% - 60%. Surveys have revealed that about 70% of the employees at Swedish offices, schools and kindergartens experience that the air is too dry during the winter season. Previous studies show that the level of relative humidity in the indoor environment influences the prevalence of respiratory infections and allergies. The purpose of this study is to investigate how the relative humidity differ between the two buildings, and if this may be a cause of the health problems that users are affected by. During many years, users have complained about the environment in the building with mechanical ventilation and that they suffer from health problems. The method used in the study is air measurements of the two parameters, relative humidity and air temperature in the two buildings using data loggers. The indoor environment is affected by the outdoor climate and therefore instruments are placed outdoors to record seasonal variations. The measurements were carried out during the period October 2014 to September 2015 to include all of Sweden’s four seasons with completely different climatic conditions. The results of this study show that the relative humidity in the mechanically ventilated building is consistently significantly lower than in the building with natural ventilation whatever the time of year and temperature indoors. This study shows that mechanical ventilation in buildings affects the indoor environment negatively with respect to human health during most time of the year and this fact must be taken into consideration for the existing as well as the planning of new ventilation systems.
文摘Poor indoor air quality is a large problem in Swedish schools, since the health of occupants may be affected. The building itself is often in focus and other building-related problems may be neglected. The hypothesis of this study is that factors other than the building itself have decisive influence on indoor environment. An assessment of these nonspecific building-related reasons for bad indoor environment has been made in the present work using surveys combined with particle measurements and comfort measurements (air humidity and air temperature). People are experiencing poor indoor air quality, the air is too dry and the temperature is uneven and uncomfortable indoors in the winter. It is important to highlight the problem of indoor environments with high particulate emissions especially in the range from 5.0 microns and larger since they are conveyers of allergens and bacteria, combined with dry air. An interesting observation regarding the ventilation system is that mechanical systems are tending to generate drier indoor air than the natural ventilation system. Results show that it is possible to decrease emissions through eliminating activity-related sources of airborne contaminants and better the comfort indoors with relatively simple measures.
文摘An important factor for comfort ratio in the indoor environment and affecting human health and well-being is the relative humidity. Studies have shown that about 70% of the staff at Swedish offices, schools and kindergartens experiences that the air is too dry during the winter season. Studies show that the relative humidity in indoor environments influences the incidence of respiratory infections and allergies. Important factors for the air environment indoors is to limit the number of airborne particles, since these are conveyors of both bacteria and viruses, and to keep the humidity at a level above 40% and below 70%, making the survival of viruses and bacteria minimized. Measurement results show that there is significant difference in the relative humidity during the winter season between the mechanically ventilated buildings with relative humidity levels below 10% than in buildings with natural ventilation. An important issue is how human health is affected by during longer periods and during much of the day live in environments with low relative humidity. Several researchers have noted that the incidence of respiratory infections increase during the winter when people are exposed to long periods of low humidity indoors. This means that the consequences of low humidity in the indoor environment should be considered and evaluated in a completely different way than is done today.
