Recommendation 4

For spaces where aerosol-generating procedures associated with pathogen transmission are conducted, the natural ventilation requirement should, as a minimum, follow Recommendation 2. Should the agent be airborne, Recommendations 2 and 3 should be followed.

Population: Health-care settings

Intervention: Room ventilation for spaces with aerosol-generating procedures

Quality of evidenceVery lowThere is indirect evidence available to show that aerosol-generating procedures are associated with an increased risk of infection and ventilation may play a role.
Benefits or desired effectsModerate (benefits sometimes outweigh disadvantages)Possibly reduced infection risk.
Disadvantages or undesired effectsReduces comfort level of occupants when hot, humid, or cold.
CostsMay be low and highLow cost if simple natural ventilation is used. Can be higher if a hybrid (mixed-mode) ventilation system or high-tech natural ventilation is used.
FeasibilityConditional to country settingsNatural ventilation is less feasible in extreme climates (extreme cold, hot, noisy, polluted).
Research gapThere is a need to determine the minimum ventilation requirements for natural ventilation in terms of variable ventilation rate and airflow direction control for aerosol-generating procedures.

From: Annex B, Recommendation GRADE appraisal tables (GRADE system)

Cover of Natural Ventilation for Infection Control in Health-Care Settings
Natural Ventilation for Infection Control in Health-Care Settings.
Atkinson J, Chartier Y, Pessoa-Silva CL, et al., editors.
Copyright © 2009, World Health Organization.

All rights reserved. Publications of the World Health Organization can be obtained from WHO Press, World Health Organization, 20 Avenue Appia, 1211 Geneva 27, Switzerland (tel.: +41 22 791 3264; fax: +41 22 791 4857; e-mail: tni.ohw@sredrokoob). Requests for permission to reproduce or translate WHO publications — whether for sale or for noncommercial distribution — should be addressed to WHO Press, at the above address (fax: +41 22 791 4806; e-mail: tni.ohw@snoissimrep).

NCBI Bookshelf. A service of the National Library of Medicine, National Institutes of Health.