Role of ventilation in airborne transmission of infectious agents in the built environment ? a multidisciplinary systematic review

Abstract

There have been few recent studies demonstrating a definitive association between the transmission of airborne infections and the ventilation of buildings. The severe acute respiratory syndrome (SARS) epidemic in 2003 and current concerns about the risk of an avian influenza (H5N1) pandemic, have made a review of this area timely. We searched the major literature databases between 1960 and 2005, and then screened titles and abstracts, and finally selected 40 original studies based on a set of criteria. We established a review panel comprising medical and engineering experts in the fields of microbiology, medicine, epidemiology, indoor air quality, building ventilation, etc. Most panel members had experience with research into the 2003 SARS epidemic. The panel systematically assessed 40 original studies through both individual assessment and a 2-day face-to-face consensus meeting. Ten of 40 studies reviewed were considered to be conclusive with regard to the association between building ventilation and the transmission of airborne infection. There is strong and sufficient evidence to demonstrate the association between ventilation, air movements in buildings and the transmission/spread of infectious diseases such as measles, tuberculosis, chickenpox, influenza, smallpox and SARS. There is insufficient data to specify and quantify the minimum ventilation requirements in hospitals, schools, offices, homes and isolation rooms in relation to spread of infectious diseases via the airborne route. PRACTICAL IMPLICATION: The strong and sufficient evidence of the association between ventilation, the control of airflow direction in buildings, and the transmission and spread of infectious diseases supports the use of negatively pressurized isolation rooms for patients with these diseases in hospitals, in addition to the use of other engineering control methods. However, the lack of sufficient data on the specification and quantification of the minimum ventilation requirements in hospitals, schools and offices in relation to the spread of airborne infectious diseases, suggest the existence of a knowledge gap. Our study reveals a strong need for a multidisciplinary study in investigating disease outbreaks, and the impact of indoor air environments on the spread of airborne infectious diseases.

Changing ventilation rates in U.S. offices: Implications for health, work performance, energy, and associated economics

“…These estimates have higher uncertainty than those described above because of the reliance on the results of a single study; however, supportive findings are available from a study of VRs and absence in classrooms [6] and there is a body of evidence [7] indicating that lower VRs may increase respiratory infections, which are a major cause of absence. For the analyses of scenarios 1 through 3, the fraction of time that economizers in existing buildings increase VRs was needed, because we assume these scenarios have no impact on VRs when economizers are activated.…”

“…In offices, for which the largest amount of data are available, higher VRs are associated with greater satisfaction with indoor air quality, fewer SBS symptoms, and improved work performance [2][3][4]. Limited research also indicates that higher VRs are associated with reduced absence rates in offices [5] and schools [6], possibly because providing more ventilation may reduce transmission of infectious respiratory illnesses [7].…”

Comparing the Markov Chain Model with the Eulerian and Lagrangian Models for Indoor Transient Particle Transport Simulations

“…The transmission of airborne infectious diseases, such as influenza (Moser et al 1979), tuberculosis (Menzies et al 2000), and severe acute respiratory syndrome (SARS; Olsen et al 2003), has become a major public concern in recent decades (Li et al 2007). Exhalation activities by an infected person, such as breathing, coughing, and sneezing, can generate particles carrying infectious viruses (Nicas et al 2005).…”

Effect of enhanced ultraviolet germicidal irradiation in the heating ventilation and air conditioning system on ventilator-associated pneumonia in a neonatal intensive care unit

“…Multiple studies have documented pathogenic bacteria, fungi, viruses and mold present in the air. [6][7][8][9][10][11][12] The HVAC itself is colonized with common nosocomial pathogens, and may constitute a significant reservoir. 9,13,14 Ventilator-associated pneumonia (VAP) is a nosocomial infection of the lung in intubated patients, including neonatal intensive care unit (NICU) patients.…”