Influenza (which causes ‘the flu’) and the coronavirus SARS-CoV-2 (which causes COVID-19) are ‘Respiratory Viruses’. ‘Respirare’ is the latin word for ‘breath’. A ‘Respiratory Virus’ infects you when you breath in. These viruses – more often then not – ‘get you’ in your lungs. Always Remember That…
That’s why it bugs me that so many ‘experts’ are downplaying the role of airborne spread – through aerosols – these days. It’s just ludicrous to deny that a respiratory virus does not ‘fly’ into and infect your lungs.
Is this the only way you can get infected with a respiratory virus? NO! Without getting too much into the details, a virus can infect you through any of your ‘mucous membrane’. Which is basically tissue on any of your orifices (mouth, eyes, nose, etc…). But it’s not called a ‘orifice virus’. So for Pete’s sake let’s just agree that COVID-19 hits you through your lungs.
What are aerosols?
Aerosols are not magical creatures. We encounter these little rascals every day. If you smell perfume, that’s an aerosol. If you smell someone’s breath, that’s an aerosol. When your fan cools you down, that’s an aerosol. If you’re using deodorant, that’s an aerosol. If you see someone smoking, that’s an aerosol. If you smell a fart, that’s an aerosol. Allow me to explain how respiratory viruses work…
Scientists actually prefer not to use the term aerosol. Because the definition of an aerosol can be explained as “a substance enclosed under pressure and released as a fine spray by means of a propellant gas”. In other words: “a substance that is enclosed under pressure and released as a fine mist by means of a propellant gas”. That’s your deodorant. Your deodorant canister contains a liquid, but as soon as you press on the nozzle, because of the pressure in the bottle, this liquid is ejected from the bottle at high speed, making it a mist.
I prefer the term “non-sedimenting droplets” or “droplet nuclei”. Sedimentation means as much as “landing”. So aerosols are basically droplets that never land and keep floating. They float into your LUNGS. Once the virus gets in your lungs and attaches to your mucous membrane (which – for the record – is the worst mucous membrane your body has) the virus does its magic. I’ll explain the magic in a different blogpost.
How do aerosols form?
First off, you have to understand the following; every time you exhale, sneeze, cough, talk, sing or scream, you are exhaling ‘water vapor’. Your lungs are filled with very, and i mean VERY, humid air. Whatever comes out of your mouth contains so-called ‘respiratory droplets’. This is why – during the COVID-19 pandemic – We have to do ‘Social Distancing‘. The theory behind social distancing is that these respiratory droplets will hit the ground before hitting you in the face. A respiratory droplet is basically a grenade. It contains a lot of things, including an amount of viral particles.
An aerosol is basically a respiratory droplet that has lost its “water weight”, making it light enough to float under the right circumstances. That “water weight” is, in the case of respiratory viruses (Influenza and Sars-CoV-2), really water.
Evaporation; “the water diet”
Evaporation is an expensive word for “drying up”. If you look at from a molecular level; Evaporation is the – through vibrations – flying apart of water molecules that otherwise stayed together (hydrogen bonds). That evaporation only happens on the surface. There are four things that affect the rate of evaporation:
- Adding energy (example; a kettle on the fire);
- Turbulence (example; the wind drying your clothes).
- Increasing or decreasing the surface area (example; a pool evaporates more then a tea cup);
- Air pressure (example; water boils sooner at a higher altitude);
Do you want your clothes dry quickly? Use a blow-dryer (heat and turbulence). Hang them outside your window when you drive on the highway (a lot of turbulence). Why do you think your dryer spins and blows warm air? EVAPORATION!
Can we protect ourselves against aerosols?
- ABSOLUTELY! JUST ADD WATER AGAIN! (Humidification)
It’s that simple. Try drying your clothes quickly in a damp room with the doors and windows closed. Not really possible, is it? Well the same applies to aerosols. By increasing the humidity, aerosols won’t form as easily. IT IS THE REASON WHY WE DON’T HAVE FLU SEASON IN SUMMER!
- ABSOLUTELY! SHOOT THEM OUT OF THE SKY! (Ionization)
We defend ourselves against an air force of aerosols with our own ACME LASER GUN. Remember ‘Marvin the Martian‘, who was always zapping Daffy Duck? That’s what ionization is, essentially zapping an aerosol.
- ABSOLUTELY! GIVE THEM A SUNSTROKE! (UV light)
Viruses are very sensitive to sunlight, more in particular, UV Light. Many Air Purifiers have built-in UVC Lights for that exact reason.
- ABSOLUTELY! LURE THEM INTO A BIG NET (HEPA Filters)
We defend ourselves against an air force of aerosols by making sure that they are sucked into a large net. That’s what an air purifier actually does. Once in the net, they get stuck and die. The best net is called a ‘HEPA Filter’ (High-Efficiency Particulate Air).
- Wear a freakin’ Mask. It’s a RESPIRATORY VIRUS!
Does humidifying the air have other benefits?
YES! YES! en YES!
- Numerous scientific studies all say the same thing; Respiratory Viruses like dry air. Not only do they float longer, they live longer! There are four theories on why this is. I’ll spare you those in this blogpost. But the bottom line is that respiratory viruses inactivate faster (expensive word for “die”) at high humidity. Every year, in January, we have the most infections with the flu, in The Netherlands. And guess what? January is the month with the lowest humidity and least sunshine. January is Respiratory Virus’ favorite month.
- The Mucous Membrane (Mucosa) is a natural barrier against viruses. Think of it as a “bunker” made of slime that kills viruses. The bigger and stronger the “bunker”, the better the protection. Slime, as you know, contains water. The more water, the more slime, the thicker and stronger our “bunker”. That is also why we are more susceptible to respiratory viruses in winter. Due to the low humidity, our “bunkers” are less strong. By increasing the humidity we also increase the walls of our bunker.