Is reducing CO2 alone enough to
protect people from Airborne viruses?

Ventilation is one of the most important factors affecting indoor air quality. Low ventilation rates, as well as carbon dioxide (CO2) concentration indoors, are associated with poor air quality which impacts health. Besides airborne pathogen transmission, ventilation rate has also been associated with reduced performance for office workers and academic performance of school children. With the pandemic, everyone emphasises CO2 as the most important factor for improved indoor air quality and advises people to reduce it, but low CO2 levels do not mean you don’t have any viruses lingering in the air you breathe.

HEPA Air Purifier School

CO2 is not an indicator of virus load indoors

 The amount of CO2 exhaled by humans whilst breathing is about the same whether speaking or singing/yelling. However, the amount of aerosols and viruses in the air varies with the number of infected people in the room and what they are doing, talking, singing, coughing, etc. This means the viral load in a room can increase much faster than the CO2 value. Therefore CO2 measurement value is not directly related to the amount of aerosol and virus particles in the air.

A high concentration of CO2 means that the indoor is not ventilated properly which increases the risk of infection.

For example, If there are 30 healthy students in a classroom, the CO2 concentration increases at a certain rate depending on the ventilation. If none of the students is infected, the number of viruses will be is low or zero. But if some of the students are infected with SARS-CoV-2, even if the concentration of the CO2 value in the room is low, there is still a high risk of infection because ventilation is not the only important factor.

Air Purifiers provide more effective protection against Coronavirus than open windows.

In a comparison test conducted by Dutch researchers at Delft Technical University, it was determined how quickly the number of virus particles in the room could be reduced using different types of ventilation and air purifiers.

In almost all test setups, air purifiers with high-grade HEPA filters gave the best results.

Air Purifier units that combine a HEPA filter with a powered fan system are a preferred option for auxiliary air cleaning, especially in higher-risk settings such as health clinics, vaccination and medical testing locations, workout rooms, or public waiting areas. Other settings that could benefit from portable HEPA filtration can be identified using typical risk assessment parameters, such as community incidence rates, facemask compliance expectations, and room occupant density.

While these systems do not bring in outdoor dilution air, they are effective at cleaning air within spaces to reduce the concentration of airborne particulates, including SARS-CoV-2 viral particles. Thus, they give effective air exchanges without the need for conditioning outdoor air.

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