Indoor relative humidity levels and perceived symptoms in elderly homes in Sweden during winter season

Abstract: For the sense of well-being and human health, a pleasant indoor environment is essential. Today, people spend about 90 % of their time indoors, meaning that they can be significantly affected by the buildings in which they spend most of their time. Older people are bound to spend more time indoors and also as they belong to the most sensitive age group, their indoor environments as elderly homes must be given attention. Previous studies have shown that the survival of some viruses and bacteria in indoor environments is mainly dependent on the temperature and the relative humidity that can affect the human health. Symptoms as dry eyes and dry throat have been reported in physically dry indoor conditions with RH levels below 20%. This study will be conducted in three elderly homes located in different parts of Sweden (North, South and in between). The major objective was to analyse how much time people stay under lower relative humidity levels during the winter months and to compare with levels reported in other studies that may lead to various health symptoms. The work was carried out in five steps. The first step was the literature study that was done to establish a base for work and to compare its outcomes for later steps. The second step was the analysis of physical measurements by gathering live data from elderly´s homes about indoor relative humidity, temperature, and CO2 levels. All the data was provided by Hemsö (management company of elderly´s homes). Factors as the indoor relative humidity, the moisture difference between indoors and outdoors and the water content in the air were analysed. As a third step questionnaires were sent to elderly´s homes on weekly basis to get the responses of experienced health symptoms from staff and about their elderly through an online application form. In the fourth step, efforts were put to find a relationship between the physical measurements and perceived indoor symptoms. The last step was further divided into two steps, one was the comparison between different locations based upon indoor relative humidity and vapour content and the second step was to compare three buildings based upon perceived health symptoms and their severity. It was found that people living in an elderly home north of Sweden, Luleå, spend a larger percentage of time under very low relative humidity levels compared to people living in the southern part of Sweden. It can be concluded that the people in the elderly home in the north of Sweden spent considerable time (78% of the time below 20% RH) during the studied winter period in relative humidity levels that have been reported in the literature to may imply symptoms. One objective was to examine the correlation between the physical measurements and perceived indoor health symptoms, but due to the limited number of responses from two buildings, it was not possible to find correlations between perceived symptoms and a dry indoor environment. Also, there could be potentially more factors which were possible for health problems for example chronic diseases, stress levels, sick building syndromes and many more, that were not covered in this diploma work.