ImpAQS (Improving Air Quality in Schools): Long-term study on ventilation and indoor air quality in Austrian classrooms 


ImpAQS (Improving Air Quality in Schools) aims to evaluate the benefit of installing CO2 monitors in Austrian school classrooms as means of improving ventilation practices, enhancing indoor air quality and reducing the risk of airborne disease transmission.

It is hypothesised that the use of CO2 monitors (with visible traffic-light displays), together with basic instruction on appropriate ventilation procedures, can reduce the mean CO2 concentration and quantifiably improve the air quality in classrooms. 

ImpAQS aims to answer the following research questions:

1.    Do classrooms equipped with CO2 monitors, and basic ventilation guidance, achieve better ventilation outcomes (reduced CO2 concentration) than those without monitors or training?
2.    Does improving indoor air quality (in classrooms equipped with CO2 monitors) provide a statistically significant advantage in terms of reducing the risk of airborne disease infection?
3.    What percentage of Austrian classrooms are adequately/inadequately ventilated according to existing norms and emerging guidance regarding airborne disease infections?
4.    Are the results for the CO2 concentration and ventilation practices dependent upon the season and/or other local environmental factors (e.g. noise, thermal comfort, air pollution etc)?
5.    Do teachers perceive the installation and use of CO2 sensors positively, negatively, or indifferently? And if positively or negatively, what are the greatest drivers and barriers to the use of CO2 monitors and achieving appropriate ventilation practices in classrooms? 

Project outline and duration

ImpAQS is an empirical study using a match-paired research design, involving a random sample of 1,200 school classrooms in 120 schools selected from across the nine states of Austria.  This is to compare the effects of interventions such as the use of CO2 sensors and ventilation guidance against a paired control sample (where CO2 is monitored but not displayed and no ventilation guidance is provided). In this way the study will capture the effect of the intervention in comparison to an equally sized control sample drawn from the same school.

ImpAQS will run for a period of around one and a half years (2.1.2023 - 31.09.2024), with the CO2 monitoring period lasting an entire year (September 2023 - September 2024). Our aim is to understand the ventilation practices of each classroom across every season of the year. Interim results will be provided to the Federal Ministry of Education, Science and Research of Austria.  The final report will include a comprehensive statistical analysis of the entire dataset, including hypothesis testing to establish whether clear statistical inferences can be drawn in relation to the ventilation practices of classrooms using visible CO2 monitoring compared to those that do not.  In addition, analytical infection risk models will be used to establish the corresponding differences in airborne viral infection risk transmission between the two groups. Based on brief qualitative feedback, provided by the school directors involved in the study, a summary of the key barriers to the provision of good indoor air quality, in each school, will add a qualitative (social) dimension to the findings. Collectively, this data will enhance our understanding of ventilation practices in Austrian schools, whilst identifying the challenges and responses needed to further improve indoor air quality.

Primary researchers involved

Univ.-Prof. Dr Robert S. McLeod, CEng – Professor of Building Physics and Sustainable Engineering at TU Graz

Univ.-Prof. Dr DI Christina J. Hopfe – Professor of Building Physics and Head of the Institute of Building Physics, Services and Construction at TU Graz

Contact Address

TU Graz
Institute for Building Physics, Services and Construction
Lessingstraße 25/III
8010 Graz

Job offers

Link to the Job Offers page

Project funding and support

Bundesministerium für Bildung, Wissenschaft und Forschung