Virus Spread Resistance Indicator

August 2023

"Version 2023" (modified calculation based on RESET).

Virus transmission in indoor spaces is so complex and diverse that it can change significantly depending on the type of virus. There are several key parameters relevant to indoor spaces, such as temperature, relative humidity, ventilation efficiency calculated from CO₂ concentration, or suspended particles present in the indoor air.

My inBiot's new Virus Spread Resistance Indicator indicates the probability of airborne virus spread in an indoor space. Based on the RESET VIRAL INDEX, it shows on a scale of 0-100 the resistance offered by the air in a space to the spread of viruses.

The indicator calculates infection potential based on scientifically proven indoor air quality metrics, such as temperature, relative humidity, PM2.5 concentration and CO₂, assessed through inBiot's monitoring technology.

Although it is currently impossible to measure airborne viruses in real time, continuous monitoring of a building's ability to minimize the potential for airborne infection is possible through a series of parameters. To do this, it is necessary to combine scientific research with real-time results in a standardized and meaningful way. This has demonstrated the direct impact of humidity, temperature and airborne particles on the rate of viral infections.

Therefore, to know the risk of infection, it is necessary to know the survival of a virus, the impact of different indoor air quality parameters on the immune system and the dose of such exposure:

[Virus survival]+[Immune system]+[Dose] = [Risk of infection].

From this information, the algorithm resulting from RESET 's research work is applied to obtain the virus indicator, calculated in real time in My inBiot from the MICA monitoring data:

- VS: Virus survival

- ISPM: Impact of PM2.5 on the Immune System

- ISRH: Impact of relative humidity on the immune system.

- PVDr: Potential Viral Dose Risk

- AIP: Airborne Infection Potential

- RVI: RESET virus indicator


Impact of the different parameters of the virus indicator:


The infection rate of viruses is significantly reduced at room temperature (20°C), compared to colder temperatures at which viruses have greater persistence. On the other hand, at high temperatures, viruses are destabilized and their infectivity is generally reduced. High temperatures can reduce the activity of viruses and, in some cases, can even inactivate them. In addition, low temperatures reduce the efficiency of our innate defenses in the respiratory tract.

Relative humidity

A relative humidity between 40% and 60% is ideal from the point of view of thermo-hygrometric comfort, although in terms of virus inactivation, 50% is the optimum level, since viruses are less active.

At significantly low relative humidity (below 40%), the mucous membranes of the respiratory tract dry out, reducing their ability to protect against the entry of pathogens into the body. At high relative humidity (greater than 60%), the proportion of pathogens in the air increases and there is a greater likelihood of mold growth.


Ventilation is the key strategy to reduce the concentration of indoor air pollutants, be they chemical compounds or biological agents such as virus. High CO₂ levels indicate a poorly ventilated space and therefore an increased risk of virus concentration in the air.


Virus transmission and virulence also depend on the size and concentration of the aerosols breathed. With typical nasal breathing, aerosols can be deposited continuously in the respiratory system. And in particular, small aerosols (those smaller than 2.5 μmn - PM2.5) penetrate deeply into the respiratory tract and have the ability to remain longer in suspension than larger particles (PM10), which are deposited on surfaces more easily, due to gravity.

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