New sensors provide clarity on the dispersion of aerosols indoors

The Sars-CoV 2 virus illustrates that ventilation systems play a special role in the spread of pathogenic germs. Most of the germs are transported in the aerosol of the air we breathe, when we cough or sneeze.


In recent years, ventilation systems have been designed with a focus on comfort and energy efficiency, which tends to be at the expense of hygiene. In order to investigate the current state of indoor air, sensors for determining aerosol dispersion were developed at the IET. In combination with an artificially generated aerosol, different dispersion scenarios are investigated by means of a "spreader" simulated in an experiment and then analysed. The data allow a situation-specific assessment of the ACTUAL state in both large and small rooms, such as entrance areas, cinemas, offices and the like. Based on the results, suggestions for improvement of the prevailing situation can be made, if necessary. Three basic methods can be summarised here:

  • The reduction of aerosol through targeted exhaust air routing.
  • Dilution of the aerosol to low concentrations
  • Disinfection of the aerosol via chemical or physical mechanisms

Figure 1: Artificially produced aerosols


Figure 2: Time dispersion behaviour of an exhaled aerosol in the direction of 10 sensors with distance in the Y- and X-axis in metres to the source (yellow). The concentration of the aerosol is highlighted in colour starting with green, orange, red and ending with the maximum value in purple.


Low-cost procedures such as adjusting the ventilation setting can already be effective and physical procedures such as "upper room disinfection" with UVC light prove to be very effective. If you are interested or have any questions, our team will be happy to support you!