Lufthygiene in Unterrichtsräumen unter SARS-CoV-2-Bedingungen

摘要

Contrary to real-life conditions, previous assessment methods used for mobile air purifiers (MAP) were based on the instant removal of high particle concentrations from a homogeneous distribution. Furthermore, the reduction of parameters as well as the balancing of additional virus loads in the room were not taken into account, which are the result of continuous MAP noise levels and consequently forced louder speech. In the simulation model of a typical classroom, the MAP distance to the (unknown) virus source proved to be a significant determining factor of the purifier function. A concentration gradient built up, which at a distance of 8 m caused a retention time of 10 min, after which virus particles first reached the MAP in a strongly diluted form. By balancing the continuous noise being emitted from the MAP in operation, the virus load in the classroom increased and could only be completely removed again in a few conformations (small distance to the source, high volume flow) or reached a minimal reduction compared to the load without an MAP operating.