The funds will go to public institutions, museums, theaters, universities and schools and are intended for the modernization of air conditioning systems up to 100,000 euros. At the same time, they can be used to purchase sensors to measure the level of carbon dioxide, an indicator of stagnant air in an enclosed space. The money will be allocated starting Tuesday.

Schools that do not have centralized air conditioning systems are urged to use mobile air purifiers, depending on the possibility of natural ventilation obtained by simply opening the windows.

However, German experts warn that purifiers that rely on ultraviolet, ionization or ozone can be ineffective against coronavirus particles and in some cases can even worsen air quality.

Germany has introduced indoor ventilation in its national strategy to combat the transmission of SARS-CoV-2 coronavirus, with Germans advised to ventilate their homes at least twice a day.

Drops of saliva released by coughing or sneezing can survive in the air for at least 8 minutes, while fine drops of virus or aerosols last for several hours.