By Paul Kasler, director of Aura Air
The link between human respiratory health and air quality is well-proven and recent studies have now begun to examine the link between air quality and increased COVID-19 death rates.
Ventilation is described by the Department of Health & Social Care as a key mitigation when controlling the far-field (>2m) transmission of SARSCoV-2 spread by airborne transmission.
Research shows that fresh air in a room can reduce the risk of infection from particles by over 70 per cent, as fresh air dilutes the particles. Increasing the ventilation rate from one litre per second per person (very low ventilation rate) to 10 litres per second per person (recommended ventilation rate in standards for many buildings) can reduce the relative risk of infection with COVID-19 of between 68-86 per cent, depending on the viral emission rate and the duration of exposure.
Particulates commonly found in circulation include those at the lower size range, possibly produced by talking, and those produced by coughs and sneezes at the other end of the size spectrum (a particle size range of <5-10 microns). In still air, research finds that the former can remain airborne for several hours, while larger droplets can travel as far as eight metres, according to research published in medical journal The Lancet.
In situations where adequate ventilation is not easily possible, a filtration system can be used. The ideal positioning for this is the middle of the room where people gather and, ideally, at a height equivalent to the average seated human head height of 1-1.5m. According to one study, placement can affect device efficiency (particle removal) by a factor of 2.5. Power output is also a consideration to prevent unwanted droplet direction and device-induced inhalation.40
C-band ultraviolet light should be well-screened from view, as it can damage the skin and eyes.
Ozone ionisers should produce less than 50-70ppb (parts per billion) of ozone to avoid damage to health
Bipolar ionisation generates positive and negative ions to destroy coronavirus.