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Incredible video. I strongly recommend watching the whole thing. It changed my priors on the dynamics of micro-droplets. The part showing how a single cough can

Incredible video. I strongly recommend watching the whole thing. It changed my priors on the dynamics of micro-droplets. The part showing how a single cough can create a room-wide cloud of virus that lingers for 20+ minutes in spaces with poor circulation was especially enlightening. I won’t feel paranoid for vacating an area with a sick person anymore, unless it’s outside or in one of those premium buildings where you can feel the air flow. Shouldn’t the government subsidize good HVAC (not just energy efficient HVAC)? It already subsidizes green energy, which helps avert a far off semi-existential risk. Good HVAC could partially mitigate an existential risk in the near future, in addition to loss of productivity and life due to seasonal flus. Of course, we should all be wearing masks when we go out during a pandemic. Less intuitively for people, we should expect sick individuals to wear masks outside of home regardless of a pandemic, and we should never ever physically go to work or school sick.

vanniv 7y ago
To be fair, they were simulating an airtight room with zero movement. Even just people walking around would create some airflow -- an HVAC would create both airflow and temperature gradient. Blowing the droplets away is effective, but also blowing them in to either each other or a surface is also effective. Evaporation also occurs -- the smallest droplets likely would evaporate long before this model shows them hitting the ground or dissipating. To your final point, I direct you to the hygiene hypothesis -- you definitely want to periodically encounter low levels of non-lethal pathogens. Yeah, people should take reasonable precautions when they are sick, and you should wash your hands whenever they're dirty or before you eat/stick your fingers in your nose (or at least 5x per day just on general principle), but we shouldn't stop having human social contact, and you shouldn't live in a Cleanroom.
- keenmaster 7y ago
  Sure, we shouldn’t be extra paranoid and literally live in a clean room. Yes, the simulated room had zero circulation, which is unrealistic. However, the point stands that micro-droplets linger far more than you’d think. We should find ways to systematically improve the health of the population. Guidelines to cough into our elbows just don’t cut it. Flu vaccines are great but they’re not enough and they’re not universal. My logic for subsidizing good HVAC also applies to other pathogen mitigation technologies. No-touch sinks in public areas are one example.

vanniv 7y ago

To be fair, they were simulating an airtight room with zero movement. Even just people walking around would create some airflow -- an HVAC would create both airflow and temperature gradient. Blowing the droplets away is effective, but also blowing them in to either each other or a surface is also effective. Evaporation also occurs -- the smallest droplets likely would evaporate long before this model shows them hitting the ground or dissipating. To your final point, I direct you to the hygiene hypothesis -- you definitely want to periodically encounter low levels of non-lethal pathogens. Yeah, people should take reasonable precautions when they are sick, and you should wash your hands whenever they're dirty or before you eat/stick your fingers in your nose (or at least 5x per day just on general principle), but we shouldn't stop having human social contact, and you shouldn't live in a Cleanroom.

keenmaster 7y ago
Sure, we shouldn’t be extra paranoid and literally live in a clean room. Yes, the simulated room had zero circulation, which is unrealistic. However, the point stands that micro-droplets linger far more than you’d think. We should find ways to systematically improve the health of the population. Guidelines to cough into our elbows just don’t cut it. Flu vaccines are great but they’re not enough and they’re not universal. My logic for subsidizing good HVAC also applies to other pathogen mitigation technologies. No-touch sinks in public areas are one example.