The assessment of air quality in unprotected hospital areas: an opinion paper.

Regarding air quality, modern hospitals include both 'protected' and 'unprotected' areas. Although recommendations exist for maintaining good air quality in protected zones, guidance for unprotected areas remains limited. This gap poses a significant risk, particularly for immunocompromised patients, who are more susceptible to acquiring potentially life-threatening healthcare-associated infections (HAIs) transmitted through the air in these settings. The aim of this review was to review existing evidence on indoor air quality in unprotected (IAQ-U) hospital areas and identify current knowledge gaps. Additionally, some proposals for assessing and maintaining optimal indoor air quality (IAQ) in these settings are presented. A narrative review of the literature on IAQ was conducted, covering the period from 2015 to 2025, and selected available recommendations on IAQ in the healthcare setting were examined. The paper is structured in two sections. The first section reviews the existing evidence on IAQ, while the second presents perspectives and proposals. Specifically, the European Society of Clinical Microbiology and Infectious Diseases could co-ordinate a pilot multi-centre study among selected European hospitals to develop guidelines for assessing IAQ-U hospital areas. Implementation of these proposals could reduce the incidence and associated costs of air-transmitted HAIs and strengthen preparedness for future pandemics.