Sensitivity analysis of SARS-CoV-2 aerosol exposure

Area of Science:

• Environmental Health
• Epidemiology
• Aerosol Science

Background:

• The transition from pandemic to endemic SARS-CoV-2 necessitates understanding indoor airborne transmission.
• Pre-vaccination controls focused on avoiding indoor situations; mitigation is now advisable.
• Assessing SARS-CoV-2 aerosol exposure requires updated models for indoor environments.

Purpose of the Study:

• To develop and analyze a time-discrete model for SARS-CoV-2 aerosol exposure.
• To conduct a sensitivity analysis of indoor airborne transmission factors.
• To inform mitigation strategies for indoor settings during the endemic phase.

Main Methods:

• A new time-discrete model was developed to quantify infectious SARS-CoV-2 aerosol exposure.
• Sensitivity analysis was performed on various indoor exposure parameters.
• Ventilation effectiveness, including window opening and air supply, was modeled.

Main Results:

• Time limitations and mask usage are potent mitigation measures for aerosol exposure.
• Effective ventilation, especially in smaller rooms, is critical and requires higher fresh air rates than standard.
• Frequent, short window openings reduce exposure dose and offer thermal benefits; long openings and large surfaces are most effective.

Conclusions:

• Standard ventilation design may be insufficient for controlling airborne SARS-CoV-2; enhanced fresh air supply is needed.
• Further research into school ventilation models and daily, time-limited student attendance is recommended.
• Reducing control measures will increase exposure doses, necessitating studies on infection rates and fatality in partially immune populations, especially with variants like Delta.