Last November, at the La Marañosa Campus, which is home to INTA’s technology center and the headquarters of the General Subdirectorate of Ground Systems, the Hispacold air treatment system based on UVC lamps was subjected to a series of tests, in accordance with strict safety procedures and a very demanding test protocol.

The tests were aimed at analyzing the biological decontamination capacity of an HVAC unit designed to provide climate control and germicidal air treatment in a railway vehicle, with a specific view to eliminating any SARS-CoV-2 virus present in the passenger compartment. The goal was to evaluate the reduction in viral load in an aerosol of the MS2 bacterial virus treated using a system based on UVC lamps, located inside the aforementioned HVAC unit in the railway vehicle.

The tests were carried out in a Class II Biosafety Cabinet (BSCII).

Given the impossibility of carrying out the tests on SARS-CoV-2 safely, the decision was made to use the MS2 bacterial virus. The MS2 bacterial virus is more resistant to UVC radiation than SARS-CoV-2, as its inactivation energy is 64 mJ/cm² compared to 6.7 mJ/cm² for the latter. Because its inactivation energy requirements are around 10 times greater than SARS-CoV-2 under UVC radiation, the use of this virus made it possible to draw conclusions with a high degree of confidence. 

From the results obtained, it can be deduced that after one air treatment cycle, the reduction of infectivity in the bioaerosol stands at 1.18 orders of magnitude (log R = 1.18). This represents a 93.4% reduction in viral load after exposure to UVC light from the air treatment system.

We can therefore conclude that the air treatment system in question was effective in reducing the viral load in the air under the test conditions.