Type of study	Randomised controlled trial (RCT) Cluster randomised controlled trial (cluster‐RCT) Interrupted time‐series studies (ITS) ‐ clearly defined intervention point Cross‐over study ‐ order of intervention	Controlled before‐and‐after study (CBA) ‐ comparable control site Quasi‐randomised studies ‐ method of allocation Other type of controlled studies, specify:
	Does the study design meet the criteria for inclusion? Yes No: exclude Unclear
Type of participants	Describe the participants included: They belong to which group: ‐ Adult working population ‐ School setting: children, young adults Do the participants meet the criteria for inclusion? Yes No: exclude Unclear
Type of interventions	Is indoor air humidity assessed? Technique: Intervention in control group: Does the intervention meet the criteria for inclusion? Yes No: exclude Unclear
Type of outcome measures	List primary outcomes: List secondary outcomes: Does the study assess a single primary or secondary outcome, qualifying it for inclusion? Yes No: exclude Unclear