Abstract
Since people spend most of their time in indoor environments, the objective of this work was to study indoor air quality and its effects on users’ thermal comfort. Based on previous data from a building with a central air-conditioning system and two mixed-mode buildings located in the humid subtropical climate of Florianópolis, southern Brazil, statistical analyses were performed. Each user’s subjective answer obtained through a questionnaire was combined with the corresponding environmental conditions measured by instruments. Results showed that improvement in air quality was associated with the reduction of air temperature and humidity ratio. Also, there was a significant influence of thermal and humidity sensation on air quality satisfaction. Users felt more satisfied or neutral with air quality for being in thermal comfort, and not because of the CO2 concentration—which means that air quality perception is influenced by factors other than CO2. This study recommends implementing an air exchange device in split air-conditioners with air recirculation commonly used in mixed-mode buildings in Brazil. It is important to provide suitable indoor ventilation to reduce pollutant concentration, ensure good air quality and prevent respiratory diseases.
Highlights
The aim of this work is to assess the occupants’ perception related to indoor air quality and its effects on thermal comfort based on data from office buildings located in Florianópolis, southern Brazil
We considered the air temperature (Ta ), mean daily outdoor air temperature (Tout ), globe temperature (Tg ), air velocity (V a ), relative humidity (RH), mean daily outdoor relative humidity (RHout ), humidity ratio (W a ) and carbon dioxide concentration (CO2 ) (Table 2)
Higher relative humidity and humidity ratio were observed in natural ventilation mode compared to air-conditioning mode, because of the air humidity reduction due to the use of air-conditioning [36]
Summary
It is estimated that people spend 60% to 90% of their time in indoor environments such as residences, educational institutions and offices [1,2,3]. In this way, it is important to study indoor air quality and its effects on thermal comfort since they are related to users’ satisfaction, performance and health [4,5,6,7,8]. Research has shown that high concentrations of pollutants have direct and indirect adverse health effects since airconditioned environments can contribute to respiratory and cardiovascular diseases [9,10]
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