30 years ago, a lot was written about Sick Building Syndrome (SBS). Groups of people got sick inside and the cause was not immediately clear. There were suspicions about the quality of the indoor climate in offices, poor air handling systems and lack of ventilation. SBS became the term for the entirety of health complaints (especially eye and respiratory complaints) that the users of a building say they experience in a long-term presence there and attribute to the building itself. Reported complaints are irritation of the mucous membranes of the eyes, nose and airways, redness of the skin, itching, headache, fatigue, listlessness and loss of concentration.

In an article from 1993, the authors wrote: “Aerogenic infections due to the spread of micro-organisms via the ventilation system are rare. Epidemics of tuberculosis, measles and virus pneumonias have been described. Usually, the ventilation system acts as a transport system and not as a source of the infection. . “ Note the word ‘transport system’. I was reminded of this when I watched a Business Class broadcast in March where Maurice de Hond sat at the table on my iPad.

Now I already hear you think “oh no, two crazy ones on TV”. But I think that is not right in this case. Maurice de Hond is media horny I know, but that does not mean that he would not be smart, or could not perform a good analysis. On the contrary, I find his story very plausible.

What is his story? The spread of the virus is (also) related to aerosols, small drops that float in the air. Contaminated aerosols can get stuck in buildings. Aerosols are formed when people talk, sing together, debate together. And the risk increases when many people come together who do that: carnival, church services, choirs, symposiums, bars. All indoor activities. But I wouldn’t like to sit on a stuffy plane now either.

A few days ago on Bloomberg.com: The new coronavirus appears to linger in the air in crowded spaces or rooms that lack ventilation, researchers found in a study that buttresses the notion that Covid-19 can spread through tiny airborne particles known as aerosols.

Also (media) virologist Ab Osterhaus nodded in agreement at Op1 (Dutch show):

The whole story of Maurice de Hond in which he also discusses climate and contamination can also be found here. He has now also written his blog. I believe that it is unjustified to put Maurice de Hond as a crazy kid. His analyzes are plausible. The question is therefore what – knowledge of aerosols as spreaders of the virus – that could mean for the 1.5 meter economy?

The virus will stay with us for a long time. With 6-8% contamination at the end of May (perhaps 15-20% at the end of July?), We have absolutely not yet achieved group immunity. And a vaccine (if it comes at all) that will last at least 8-12 months, I think. So we must learn to deal with this virus without increasing the risk of a second (and third) exponential curve. For the sake of convenience I now call that the 1.5 meter economy (where it is actually better to talk about 1.5 meter society, and even better about a Corona Society), I do not want that 1.5 meter take it too literally.

The objective of that 1.5 meter economy (The Corona Society) is:

• allow maximum economic and social activities again.
• Preventing Rt from exceeding 1 (and an exponential outbreak again)
• Our health system a) increase (so more IC capacity!) And b) no longer exceed capacity.

The main lines I wrote on April 20 “The exit strategy: What could a possible timetable look like, and what does a 1.5m economy mean for us? Now focus on our economy again, and prevent even greater damage to our social and economic system. “ But are there any additions needed to this piece? Perhaps.

IF aerosols in buildings are also a problem THEN:

• Do we have to ventilate a lot at home and in the office, or open all windows?
• Is singing or screaming or talking loudly together in a small space at risk.
• Are there really places where you better wear (correct) mouth masks.
  • So, wear face masks in public transport (and on the plane).
  • Do you visit large supermarkets? Just wear a mask too.
• Is not outside advice as much as possible. Find nature with your family!
• Should we take a closer look at the Hygienic design of our buildings:
  • Placing UV / pulsed light in air ducts?
  • Additional Airosol filtering (hepa filters)
• Event where large people come together inside, postpone this as long as possible, even if you could keep 1.5 meters away.
• Can small-scale outdoor events start slowly (if kept away), think of Formula 1 in Zandvoort. Or professional football without an audience in the stands (or half).
• Can open small terraces outside (if kept 1.5 meters away). I also see now problems when opening outside beach tents or campsites.
• Can all parks in the Netherlands open (if 1.5 meters away).
• Zoos and Amusement Parks will be open this summer (except for their indoor events, not entering a tropical greenhouse, for example).
• Team sports are allowed again in groups (but not with a large audience). And then take a shower at home (so no beer in the canteen).
• Within events where large groups of people come together, so preferably not:
  • No cinema
  • No indoor concerts
  • No large symposia inside.
• Keeping the elderly at home for as long as possible in a modern and well-ventilated house.
• Ventilating and modernizing air treatments in care homes

In short, the advice should be: go outside with your family (but keep your distance from third parties), avoid coming into contact with large groups of strangers where there is a lot of noise, especially if this group of people are indoors.