<div>Fig. 1 Schematic presentation of the 30 m<sup>3</sup> SARS-CoV-2
test room.</div><div>A venturi injector was used to mix the aerosolized virus into the air
with an airflow rate of 12 L/min via a compressor to deliver the mixture
to the test room for 20 minutes. The aerosolized virus was delivered
into the 30 m<sup>3</sup> test room through a leakproof plastic
pipeline controlled with a ball valve. In the meantime, the fan was
operated to ensure airborne virus homogenization. The humidifier fixed
the humidity of the test room to 40%, and the air conditioning system
set the temperature of the test room to 20<span class="ltx_Math math v1">\(\mp 1\)</span> <sup>o</sup>C
before turning the heater on.</div><div>A schematic presentation of
the electric heater used in the experiments is given in Fig. 3. The
electric heater consists of a fan and stainless steel electric tube
heating elements. The fan draws the air inside the air tunnel. While the
air passing through the heater gains heat energy by interacting with the
heating elements located perpendicularly to the airflow direction,
increasing the outlet air temperature of the heater within a few
seconds.</div>