Virus particles contaminate the mask’s surface, and may spread to you while handling the mask.
Is this a big deal, given that COVID doesn’t really spread via fomites? Or is the concern: The virus particles will be so close to your mouth that you’ll just inhale them off of the mask?
Thank you for the question. I’ll add my response to my answer.
Keep in mind that the filter surfaces (where the air flows through) of the mask may have spent hours collecting COVID particles from the atmosphere, since you’ve been continuously pulling contaminated air through the mask. The filter surfaces may have thousands of times the level of contamination typically seen in solid surfaces. It’s best to handle potentially contaminated masks by the straps, especially when removing the mask. If you absolutely must touch the mask itself, avoid touching filter surfaces, and instead touch a portion of the mask’s edge that’s away from your mouth and eyes. However, virus can still potentially transfer to your hands, even with proper handling (source). Thus, you should wash your hands after handling a potentially contaminated mask.
Reaerosolization of filtered particles is possible, but seems to only occur to a significant degree when the humidity is low and the particles in question are large and dry (source, source). Virus particles are typically either small and dry or large and wet (when suspended in water droplets), so I don’t think this is the primary concern. I guess avoid inhaling too close to the mask’s outer surface if you’re worried about this.
Keep in mind that the filter surfaces (where the air flows through) of the mask may have spent hours collecting COVID particles from the atmosphere, since you’ve been continuously pulling contaminated air through the mask.
How do you get into a threat scenario where you would assume constant exposure to COVID particles in the atmosphere?
In Germany, we have an app that measures whether or not I’m near people who then get tested positively with COVID-19. While only ~10% of infected people actually use it, that gives an idea of how much exposure there is. In all that time I traveled in public transportation I was never exposed to a person who then tested positively.
This suggest to me that exposing myself to multiple people with COVID-19 in a single day is very unlikely and I don’t spend more then 20 minutes exposed to the same person.
People rarely talk, laugh or scream on public transport, so the risk is much lower compared to somewhere like a bar or hospital. Also, I’m talking about relative contamination levels. Even if you’re only lightly exposed for 20 minutes, the concentration of virus on your mask is probably ~hundreds of times higher than the concentration on your clothes.
Consider the volume of air you breathe in 20 min. 95% of the virus in that air is now on your mask. Compare that to the volume of virus that settles out of the air onto your clothes. Considering COVID can remain in air for hours, that amount is likely much smaller.
Is this a big deal, given that COVID doesn’t really spread via fomites? Or is the concern: The virus particles will be so close to your mouth that you’ll just inhale them off of the mask?
As far as I understand there’s also something like a minimum effective dose for COVID-19, which I wouldn’t expect to be reached that way.
Thank you for the question. I’ll add my response to my answer.
Keep in mind that the filter surfaces (where the air flows through) of the mask may have spent hours collecting COVID particles from the atmosphere, since you’ve been continuously pulling contaminated air through the mask. The filter surfaces may have thousands of times the level of contamination typically seen in solid surfaces. It’s best to handle potentially contaminated masks by the straps, especially when removing the mask. If you absolutely must touch the mask itself, avoid touching filter surfaces, and instead touch a portion of the mask’s edge that’s away from your mouth and eyes. However, virus can still potentially transfer to your hands, even with proper handling (source). Thus, you should wash your hands after handling a potentially contaminated mask.
Reaerosolization of filtered particles is possible, but seems to only occur to a significant degree when the humidity is low and the particles in question are large and dry (source, source). Virus particles are typically either small and dry or large and wet (when suspended in water droplets), so I don’t think this is the primary concern. I guess avoid inhaling too close to the mask’s outer surface if you’re worried about this.
How do you get into a threat scenario where you would assume constant exposure to COVID particles in the atmosphere?
In Germany, we have an app that measures whether or not I’m near people who then get tested positively with COVID-19. While only ~10% of infected people actually use it, that gives an idea of how much exposure there is. In all that time I traveled in public transportation I was never exposed to a person who then tested positively.
This suggest to me that exposing myself to multiple people with COVID-19 in a single day is very unlikely and I don’t spend more then 20 minutes exposed to the same person.
People rarely talk, laugh or scream on public transport, so the risk is much lower compared to somewhere like a bar or hospital. Also, I’m talking about relative contamination levels. Even if you’re only lightly exposed for 20 minutes, the concentration of virus on your mask is probably ~hundreds of times higher than the concentration on your clothes.
Consider the volume of air you breathe in 20 min. 95% of the virus in that air is now on your mask. Compare that to the volume of virus that settles out of the air onto your clothes. Considering COVID can remain in air for hours, that amount is likely much smaller.