Air purifiers not enough to prevent Covid-19 transmission

Mobile air purifiers can help remove allergens and viral particles from indoor air, but they do not protect fully against coronavirus spread. — dpa

Despite the ongoing Covid-19 pandemic, many people don’t want to stop seeing friends and family.

Portable air purifiers seem to be a good solution here for indoor gatherings.

However, they can easily give a false sense of security, warns a German consumer advice centre.

Although the devices can reduce the number of allergens and viruses in the air in a room, they cannot prevent transmission when in close contact with someone (i.e. less than 1.5m apart).

Therefore, they are only one of a number of protective measures that should be taken to reduce aerosols indoors, according to the consumer advice centre.

Other measures such as opening windows and physical-distancing remain essential.

To reduce the concentration of allergens and viruses in the air, it’s best to ventilate for five minutes with the window(s) wide open.

Cross-ventilation, which involves opening windows at opposite sides of a home and keeping internal doors open, is also good for letting stale air out.

Windows that are designed with hinge technology and can be left open at a tilt, on the other hand, are less effective.

If you’re looking to buy an air purifier for your home, you should consider the following points.

Firstly, particulate filters can hold back virus-containing particles from the air, but not all filters are created equally.

According to the Association of German Engineers, devices should have High Efficiency Particulate Air (HEPA) filters of class H13 or equivalent.

In addition, the filters must be replaced after a certain operating time, as the filter performance decreases over time.

Secondly, the amount of air to be filtered changes depending on the size of the room and the number of people.

The performance of the device must be adjusted accordingly, which can lead to higher power consumption and noise levels.

If several rooms are being used at the same time, each room needs its own air purifier.

Finally, ozone air purifiers can add harmful ozone gas to the air in the room.

Some devices ionise the air in the room, but this alone does not remove any offending viral particles.

In addition, ozone can also form during ionisation.

Air purifiers with ultraviolet-C (UV-C) light should only be used if it is certain that no UV radiation is released from them, as the radiation can cause damage to the skin and eyes. – dpa