Does AC Spread COVID? Air Conditioning and Virus Risk

Creator: Medica Health team
Published: 2026-10-28
Keywords: does AC spread COVID, air conditioning

medica-seed-editor · October 28, 2026, 7:37am

This article examines the question of does AC spread COVID and how indoor air quality influences the transmission of infection, providing guidelines for prevention within facilities.

How Does Infection Spread in Enclosed Spaces?

Most people spend approximately 90% of their time in indoor environments, where pollutant levels can be up to 100 times higher than in outdoor air. The virus spreads through several pathways:

Direct Contact: Via droplets larger than 10 micrometers, which travel between 1 to 2 meters during coughing, sneezing, or speaking.
Contaminated Surfaces: When droplets land on tables or control panels, and a healthy person touches them and then touches their eyes, nose, or mouth.
Airborne: Particles smaller than 5 micrometers can remain suspended in the air for hours or days without professional cleaning; the virus itself has a diameter between 80 and 160 nanometers.
Fecal-Oral Route: Some data suggest the possibility of transmission this way, so it is advised to cover the toilet before cleaning it.

Analyzing Does AC Spread COVID

There are no conclusive studies that definitively prove or disprove the role of cooling devices in spreading the virus, although some observations suggest a possibility. A study in a five-story restaurant equipped with a central air conditioning system observed several infected individuals sitting at adjacent tables. Although analyses did not show the virus inside the air exchange unit, researchers suggested that the airflow path from the exchange unit may have contributed to transporting the virus between tables.

The Role of Air Conditioning in Transporting Pollutants

The specifications of the system used affect the level of safety:

Filters: Filter quality plays a major role; some filters prevent the escape of impurities smaller than 5 micrometers. Since the virus is much smaller, it may remain trapped in the filter. However, the virus has been detected in air exchange units in some hospitals.
Gas Exchange: Systems that exchange air between the interior and exterior help reduce the risk of spread.
Temperature and Humidity: Opinions vary here; while low humidity and temperature contribute to the survival of the SARS virus, there is no conclusive evidence confirming the same applies to the coronavirus.

Groups Most Affected by Air Quality

Certain groups are more sensitive to air quality in enclosed environments, including:

Children up to 16 years old.
Older adults over 60 years old.
Pregnant women, those with compromised immunity, and people with chronic respiratory diseases.
Individuals who have recently undergone surgery.
Pet owners, such as those with dogs, cats, and birds.

Tips to Limit Infection Spread in Facilities

To ensure a safe environment, it is preferable to follow these steps:

Hire maintenance experts to inspect filters, gas exchange units, and humidity controls.
Ensure good ventilation via windows, even when air conditioning systems are in use.
Run ventilation devices at low speed two hours before starting work, and continue operating them at night and on weekends.
Keep restroom ventilation running constantly while keeping windows closed to ensure the correct airflow direction.
Clean or replace filters outside the building while wearing gloves and an FFP3 mask if possible.

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