Aerosol and COVID-19 infections

Aerosol and COVID-19 infections

One study from China says that, of 7,324 reported infections, only one case with two infections was traced back to an open-air setting (Indoor transmission of SARS-CoV-2, Hua QIAN1,*, Te MIAO2,*, Li LIU3, Xiaohong ZHENG1, Danting LUO1, and Yuguo Li2,4,*).

This means that COVID-19 is the first and foremost disease that transmits indoors. An aerosol is a suspension of fine solid particles or liquid droplets in air. During breathing, exhaled aerosol particles are generated. These aerosols particles usually range between 0.2 and 0.6 μm and can transport viruses out of the lungs and be present in the room air for hours.

When two people are talking At the typical conversational distance, exposure to aerosols is about 2000 times greater than exposure to droplets. (Chen 2020)

Even without communicating, If an infected person is present in the room long enough, it will saturate the air with infected aerosols and if healthy persons are present long enough in such an environment, they have a high risk to get infected by purely inhaling infected air. Aerosol particles are so small that is very difficult to filter (common face mask are not effective against aerosol particles) and new strategies must be developed to mitigate the risk of the infections.

For example, air-conditioning devices help to spread infections as aerosols are more effectively spread through the room within the air drought (especially rooms with poor ventilation).

Proper ventilation without recirculation will help decrease the risk of getting infected.

Depend on circumstances, normal ventilation rates might not be enough to mitigate the risk to be infected. UV-C technologies are perfect to lower the risk of getting infected within indoor space.

Devices like MUONIO UV-L 110 are installed in the room where potential infections could happen. With an airflow of 120 m3/h and 2 powerful UV-C lamps that are concealed within the unit (humans are safe to be present in the same space), it will continuously disinfect the room. COVID-19 and other potentially infectious microorganisms will be killed within one pass. Room with a size around 20-25m2 will be completely disinfected 2-3 times per hour.

Sizing the units to the room size matters. There are spaces with a lower and higher risk of infections (there are factors like the number of people, room size, ventilation rate, etc.)and in some cases, one unit will be enough for relatively large spaces and vice versa.

An excellent source on Aerosol and COVID-19 infections is here: https://first10em.com/covid-19-is-spread-by-aerosols-an-evidence-review/