Indoor air pollutant sources are crucial in assessing IAQ, especially when outdoor air pollutant concentrations are low. In the present study, PM mass concentrations in a range of five sizes; CO, CO2, O3, NO, NO2, and TVOC concentrations; along with temperature and relative humidity were monitored in three indoor locations of a university. The monitoring took place in a building dedicated to teaching undergraduates. The first two locations, a professor’s office and a computer centre (laboratory), were not refurbished. The classroom under study is refurbished and now is airtight, as are all of the classrooms in this building. Air purifiers were installed in all of the classrooms to prevent the transmission of infectious pollutants. In all monitored locations, people were the main indoor source of PM, CO2, and TVOC. The operation of twelve computers in the small laboratory did not contribute to the air pollution, at least for the examined pollutants. The air purifier decreased the PM concentrations, but not the gaseous air pollutants.

Energy efficiency in museums and buildings that house works of art or cultural heritage appears to be a difficult achievement if indoor air quality has to be kept at appropriate levels for artefacts’ long-term sustainability. There is a gap in our scientific literature on the relationship between indoor air quality and energy efficiency, meaning that there are no numerical data that examine both of them simultaneously, although this is a theme that is broadly discussed by museum managers, curators, and scientists. It is certain that the two parameters, indoor air quality (IAQ) and energy efficiency (EEF) are conflicting and difficult to reconcile. Furthermore, IAQ is not only the determination of temperature, relative humidity, and CO2, as is usually presented. Using green or renewable energy does not make a building “energy efficient”. Hence, in the manuscript we review the literature on IAQ of museums and exhibition buildings, in conjunction with the consideration of their EEF. Hopefully, reviewing the literature for this problem may lead to carefully designed monitoring experiments. The selection, application, and testing of appropriate technological measures can lead to a new balance between the two conflicting parameters. Not only must solutions be found, but these solutions are necessary in the mitigation battle against climate change.