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Mathematical model to minimize the infection risk from respiratory viruses

ContagionDropletRelative humidityTemperaturevirus spread


The invention consists of a device that, based on the external temperature and relative humidity, calculates the correct interpersonal distance that must be kept to drastically reduce the chances of contagion from respiratory viruses, including coronaviruses. The device is based on a mathematical model that calculates the distance and lifespan of saliva droplets (virus vectors) based on external conditions.

Technical features

The main vehicle of infection of respiratory viruses, including coronaviruses, is represented by the diffusion into the air of the droplets of saliva emitted by normal human activities (breathing, speaking, coughing, etc.). To avoid contagion, one of the recommendations, especially when it is not possible to wear the mask, is to maintain a safe interpersonal distance. This is currently standard and decided a priori but it is not always sufficient: infact the lifespan and the distance travelled by droplets is not constant, but depend on their size and on evaporative processes.

An innovative mathematical model has been developed and is capable of calculating the maximum distance travelled and the maximum lifespan of the droplets based on their size and external conditions such as temperature, relative humidity and air speed. This model can be integrated into applications or software for the development of devices that automatically detect environmental conditions and immediately provide the recommended interpersonal safety distance.

Possible Applications

  • Limitation of infections in any room
  • Indications on how to structure the air conditioning system to avoid contagion
  • Development of individual or collective devices to reduce the risk of contagion in public places
  • Development of apps / software to reduce the risk of contagion in public places


  • The calculation of the correct safety distance to prevent virus infections is based on real external conditions.
  • Immediate result
  • Very simple and cheap device
  • It can be used indoor and outdoor
  • Applicable to all viruses carried by drops of saliva in the air.