Christmas, aerosols and COVID-19

Christmas a danger? Not if you ask Atze Boerstra, indoor environmental expert and director of bba indoor environment. The key is smartly avoiding breath aerosols, which float in the air and can contain virus particles. Six expert tips for an aerosol-poor Christmas. Also handy after the holidays!

Tip 1. Buy a bizarrely large Christmas tree

The larger the Christmas tree, the less reverberation in the room, and the softer we automatically talk to each other. As you have probably already learned, there is a direct link between voice volume and contamination risk. Talking and shouting loudly produces a factor of 30 more viruses than being quiet or whispering. So fill the room with Christmas tree.

Tip 2. Use the anti-COVID button in your car during transport

Hero of private transport: the ventilation knob. Set the ventilation to high, and open a window every half an hour (in the back, please, so that we don’t catch a cold). An alternative for two people in one car, not belonging to one family:

  • Driver front left, guest rear right (one and a half meter rule).
  • Window (partially) open front right and rear left (air flow prevents breath communication between the two occupants).

With an additional mouth mask, the risk of infection in the car is nil, according to Australian research by Knibbs & Morawska.

Tip 3. Make it uncomfortable for aerosols

Aerosols find it most pleasant when they all hang together in a stuffy, unventilated room with stagnant air. Then they can survive for a few hours. So ventilate a lot if there have been visitors: open windows against each other for 10 minutes. By the way, keeping all windows ajar is the best.

Tip 4. Don’t tidy up!

Viruses can survive on some surfaces, but the longer you leave them there, the less is left. They are the cotton balls among the micro-organisms: wait a (long) while, then they will automatically become inactive, very different from fungi, for example. See the famous American study by Doremalen and co. Our advice: do not clear the table for the first 24 hours. If all goes well, any viruses on spoons and glasses will not survive the night.

Tip 5. Give instant useful gadgets as a gift

There are plenty of handy gadgets that contribute to an aerosol-poor Christmas: the electric body warmer or of course the “fun” face mask. But the very best (and most original) Christmas gift is of course the CO2 meter. If it becomes too stuffy and the virus concentration may build up, the meter will give an alarm: ventilate, now! Handy, because you forget to ventilate when it is cozy. Unpack immediately and put it on the table during Christmas dinner.

Tip 6. Size matters

Maybe you already figured this out… but: if you have doubts about where you will be celebrating Christmas this year, choose the largest house, or at least the largest living room. With more space, aerosols are blown away more, which saves a lot of contamination risk. If the living rooms are the same size, go for the house where you can best open the windows against each other.

Merry Christmas everyone!

And stay healthy.