Indoor air quality in schools plays a crucial role in children’s health and ability to learn. Poor air quality, caused by pollutants such as fine particles (PM2.5) and volatile organic compounds (VOCs), can negatively impact respiratory health, concentration, and cognitive development. Given that children spend a significant portion of their day in classrooms, ensuring a safe and healthy learning environment is essential. 

The aim of the LEARN study is to gain a better understanding of indoor air quality and its effects on the health and well-being of school children, better ways to characterise air quality and ways to improve it. The LEARN project evaluates the indoor air quality and exposure levels of children in schools across Belgium, Denmark and Greece. For this purpose, cohorts of children between 9 and 12 years old are recruited through their schools, and certified (biomedical) researchers from UHASSELT (Belgium), Aarhus Universitet (Denmark) and Envirometrics (Greece) are performing the clinical measurements, which may include measuring blood pressure, collecting blood and urine samples, and performing cognitive tests. In addition, an air purification intervention is conducted with advanced filtering equipment from MANN&HUMMEL in children’s classrooms to see if it leads to improvement in air quality and health and well-being parameters. 

Since children are a vulnerable population, conducting research with them requires strict ethical guidelines to ensure their protection, comfort, and rights.

 

A three-step approach to informed consent 

The LEARN project prioritises children’s safety and well-being by implementing strict ethical measures. These measures ensure that children and their families are well-informed, and that participation is entirely voluntary. Informed consent is gathered at three levels:

• School consent: Depending on geographical location, schools are contacted for participation. The headteacher is informed about the purpose of the study, who discusses the feasibility of the study with the teachers. Consent is sought from the headteacher before starting the study.   
• Parental or guardian consent: Before any child participates in the LEARN project, their parents or legal guardians must provide written consent. This ensures that families understand the research objectives, procedures, and any potential risks. Information meetings are therefore organised at the start of the study to inform parents or legal guardians.  
• Child assent: In addition to parental consent, verbal consent is also sought from the child at all times when measurements and samples are taken. If the child does not give verbal consent, a measurement or sample will not be taken. Both the child and the parent(s)/legal guardian may decline participation at any time.  

 

In advance of the study, the parents and children receive easy-to-understand explanations about the study. This includes what will be measured (such as air quality, cognitive tests, and health assessments), how the data will be stored and used, and their right to withdraw at any time without consequences. An information brochure was developed both for parents and children to inform them about the study. This information was adapted to their level of readability and designed in an appealing format. The brochure is available at: 

• Dutch joint version (for parents and children) 

• Danish version for parents and Danish version for children 

• Greek version (work in progress) 

Protecting Children’s Rights and Well-being

Before the start of the LEARN study, all researchers are briefed about the standard operating procedures. These operating procedures are designed to minimise potential risks, while maximising benefits. The researchers are responsible for following these strict procedures correctly, and recording the measurement in a legible way.  

Some clinical and molecular measurements, such as blood samples or cognitive assessments, might be unfamiliar to children. The local researchers make sure that the procedure is non-invasive and performed in a child-friendly way. As such, blood samples are only taken if specific consent was provided by both the guardian (through the consent form) and the child (verbally). To enhance the child’s comfort a local anaesthetic cream is applied that provides a local skin numbing effect. In this way, the skin is locally and temporarily numbed. 

Children participating in the study receive free health screenings, including blood pressure checks and assessments of their cognitive function. If any abnormalities are noted in the measurements, this will be further evaluated to decide whether it is necessary to notify a participant’s parent or guardian. The participant’s parent or guardian will then receive both verbal and written information with the recommendation to seek assistance from the attending physician. 

 

Privacy and Confidentiality

All information obtained is kept confidential and the data used for analysis does not contain any information about the identity of the participants. Participants’ contact information is stored in an encrypted form for privacy protection in accordance with GDPR standards. Temporary access to this file can only be obtained by the head of the research groups, and archiving notes are taken about the access to this file.  

The results of this study will be used anonymously for scientific purposes, and reported on group level. Clinically interpretable results will be communicated to the participants through a report/diploma, and blood results will be communicated to parents by e-mail.  

 

Ethical Oversight and Approval

Before the LEARN study begins, it undergoes rigorous ethical review and approval to ensure it meets all legal and ethical standards. The research is reviewed and approved by local ethics committees in Belgium, Greece, and Denmark, ensuring that the study aligns with national and international ethical guidelines. 

• Belgium: The study was approved by the Medical Ethics Committee of Hasselt University on October 18 2023 (B1152023000017). The person responsible for this study is Prof. Dr. Tim Nawrot (tim.nawrot@uhasselt.be). Each participant has the right to see their personal data and have them corrected, or deleted by contacting the data protection officer of the researcher centre (dpo@uhasselt.be). 

• Denmark: The Danish study protocol was approved by the Ethical Committee in Central Denmark Region on November 22nd 2023 (ref. no. 1-10-72-130-23) and reported to “Fortegnelsen” [the “Record” at Aarhus University] and the Danish Data Protection Agency (journal no. 2022-0367531/3134). The person responsible for this study is Prof. Dr. Torben Sigsgaard (ts@ph.au.dk). Each participant has the right to see their personal data and have it corrected or deleted. In the Danish cohort studies, only urine samples and other health-related measurements such as blood pressure, height, weight, etc. are collected. Blood samples are not collected.  

• Greece: The cohort study in Greece will start in autumn 2025. Ethical approval for the Greek study is in progress, and all necessary approvals will be obtained prior to study commencement. Envirometrics will ensure compliance with all national ethical standards and data protection regulations, prioritising the welfare and voluntary participation of all children involved. No blood or urine samples will be collected. The person responsible for this study is Chara Karakosta.

 

Conclusion

The LEARN project is committed to conducting research that not only advances scientific knowledge but also prioritises the health, rights, and dignity of children. By implementing strict ethical safeguards—such as a three-step consent and ethical oversight—the project ensures that participation is safe and respectful.  

The findings from this study will help improve indoor air quality in schools, ultimately benefiting children’s health and learning environments. It will help policymakers and health professionals to develop better strategies to improve indoor air quality in schools. Importantly, the study balances the risks and benefits to ensure that children are protected while contributing to valuable research and educational awareness.