Changes in Concentration of Carbon Dioxide and Temperature in University Classrooms

Abstract

This study aims to observe variations in temperature, relative humidity, and carbon dioxide concentrations in university classrooms without mechanical ventilation throughout the day. Over three days, two classrooms in Riga Stradiņš University, equipped solely with natural ventilation, were evaluated for variations in indoor air quality. Observations were recorded using the Aranet4 sensor during actual study sessions with varying numbers of occupants, and ventilation periods marked by window operations. The recorded parameters were compared with established indoor air quality guidelines. The results showed that the relative humidity remained within the ideal range (40%-60%) throughout the observation period. Indoor temperature varied between 18 °C to 26 °C, with noticeable increases during practical study sessions and decreases during ventilation periods. The carbon dioxide levels consistently exceeded the safe limit of 1000 ppm during all study sessions, with the time taken to exceed this threshold being directly proportional to the number of occupants. The findings underline the need for strategic ventilation interventions and classroom arrangements, considering occupancy and room size to promote healthier learning environments. Further research incorporating occupant surveys and including diverse educational settings is recommended. Keywords: indoor air quality; natural ventilation; classroom environment; carbon dioxide; relative humidity; temperature.