This October, the eco3 air purifier was rigorously tested under strict safety conditions and according to stringent testing criteria, at La Marañosa Campus, INTA’s technology centre, where the headquarters of the Subdirectorate General, Land Systems, is based.

The trials aimed to evaluate the extent of the reduction of viral load in an aerosol of the bacterial virus MS2 when it is treated using Cold Plasma - a treatment involving ionisation.

The trials were carried out inside a 15-meter long coach equipped with eco-3 air purifiers.

Under current legislation regarding “the protection of workers from risks related to exposure to biological agents in the workplace”, the facility where such tests are carried out must be biosafety-level-equipped. SARS-Cov-2 is categorised as a Biosafety level (BSL) 3 risk (with BSL4 the highest risk category) and any tests involving this virus must therefore be carried out using biosafety cabinets, which use carefully controlled airflow or sealed enclosures to prevent infection.

Such an environment was impossible to replicate safely inside a vehicle using the SARS-CoV-2 so the MS2 virus was chosen instead as it is 10 times more resistant than SARS-CoV-2 and can only be inactivated with a 64mJ/cm² dose compared to the 6,7 mJ/cm²  dose needed to inactivate the Covid-19 virus. This means the effect of the eco3 air purifier on SARS-CoV-2 would be far more powerful than its effect on the MS2 virus.

The independent trials concluded that the air treatment systems - the eco3 air purifiers - installed in the bus’ HVAC systems - were effective in reducing the MS2 viral load by 99.7% under the test conditions.

How does eco3 work?

When HVAC systems are in operation, the eco3 air purifier emits ions into the air, creating an environment free of viruses, including SARS-CoV-2, microorganisms, bacteria, germs, allergens and dust particles.

In addition, during the ion-generation process, ozone is produced in very low concentration (<0.05 ppm), which is harmless to passengers. This eliminates unpleasant odours and increases the oxygen concentration in the passenger compartment, reducing feelings of tiredness among passengers and drivers.

The eco3 air purifier is sited inside the return air equipment where the cleaning and disinfection of the interior air takes place and where the HVAC equipment’s own vents distribute the treated air back into the vehicle interior.

Indoor air renewal

Constant interior air renewal is also key in protecting the health of passengers and drivers. Hispacold HAVC systems are designed to work with a mix of interior and replacement exterior air, which before being heat treated and introduced into the passenger cabin, passes through a filtering section, where most potentially harmful particles are removed, improving interior air quality.

Bioaerosols - airborne particles of biological origin or that are biologically active - can affect living beings through infections, allergies, pollution and irritation are a main cause of the transmission of infection. Therefore, indoor air quality, which is achieved through ventilation and filtration, is crucial in preventing the transmission of pathogens among passengers.

Indoor air quality is affected by occupancy levels. Minimum fresh air ventilation requirements are about 2.5 to 4 l/s per person, so at least 10 to 16 complete air supply renewals inside the vehicle must be guaranteed every hour. Therefore, complete air renewal must take place inside the vehicle every 4 to 6 minutes.

Hispacold's HVAC systems guarantee an outside air flow of between 800 and 1000 m³/h at all times with interior air being renewed every 3 or 4 minutes, exceeding regulation requirements of the regulations, as long as 0% to 100% of external air is being renewed by the HVAC system.

Proven effective against bacteria and fungi by SGS and Seville University

eco3 has proved to be highly effective in vehicles in which it has been fitted. SGS, the world leader in inspection, verification, testing and certification, has also tested it and certified its efficacity.

According to the UNE 100012:2005 standard for indoor air, the maximum recommended count for mesophilic aerobic flora is considered to be less than 800 CFU/m³ of the total - above which it recommends corrective measures being taken.

The Department of Chemistry Analysis at Seville University’s Chemistry Faculty tested the eco3 air purifier in buses and coaches. Bacterial and fungal cultures taken from vehicles with, and without the air purifier, were laboratory-tested. Results showed the total number of units formed by bacterial colonies (CFU/m³) was reduced by 93% in samples taken from vehicles equipped with the eco3 air purifier.