11-10-2020, 10:46 AM
The study spoke of the mandates for indoor mask wearing.
As I indicated earlier, at walking pace & quiet breathing, you exhale the volume of a 4" diameter sphere of air every 18' (exhalation spread over about 9'). In cooler weather, I believe this air quickly rises above your head before it moves away from your head. If exercising, you'll blow a larger volume of air forward and down but I didn't estimate how much or how often.
I've mostly focused on the aerosol particles, but it has been demonstrated the droplets can go much further than even 10' with the right breeze (whether from a fan or nature). While the volume in which they exist rises as the cube of the distance, I believe they tend to remain a cloud of droplets. (I recently put a blue-colored liquid chemical in a pool with a decent flow of water from the pump. I could still see the blue (very diluted, but visible) as it circulated around the diameter of the pool and came back to me after traveling 30 yards, in a minute or two.)
While you may not need your mask if you are outdoors, remember that its purpose is to block the virus particles, not disinfect them. Every time you take it off or put it on, you will flex the material and wave it in the air or drop it on a surface, possibly raising a cloud of what is on the inside or outside surface, plus the possibility of touching the surface. I've not seen anyone study the surface of masks, except one study that showed virus was found on the outside of masks of infected persons who had coughed in their mask. I'd worry about that if I were eating at a restaurant and repeatedly putting on & off my mask.
I normally wear a KN95 mask, but recently used a surgical mask for a day. I found it to feel like no mask at all. Air could find its way around the mask as I breathed in and out. I have done manual labor in a KN95 mask in 100F weather and found that I had to take mask breaks (in my car) to catch my breath and let the moisture (which impedes air flow) evaporate from the inside of the mask.
As I indicated earlier, at walking pace & quiet breathing, you exhale the volume of a 4" diameter sphere of air every 18' (exhalation spread over about 9'). In cooler weather, I believe this air quickly rises above your head before it moves away from your head. If exercising, you'll blow a larger volume of air forward and down but I didn't estimate how much or how often.
I've mostly focused on the aerosol particles, but it has been demonstrated the droplets can go much further than even 10' with the right breeze (whether from a fan or nature). While the volume in which they exist rises as the cube of the distance, I believe they tend to remain a cloud of droplets. (I recently put a blue-colored liquid chemical in a pool with a decent flow of water from the pump. I could still see the blue (very diluted, but visible) as it circulated around the diameter of the pool and came back to me after traveling 30 yards, in a minute or two.)
While you may not need your mask if you are outdoors, remember that its purpose is to block the virus particles, not disinfect them. Every time you take it off or put it on, you will flex the material and wave it in the air or drop it on a surface, possibly raising a cloud of what is on the inside or outside surface, plus the possibility of touching the surface. I've not seen anyone study the surface of masks, except one study that showed virus was found on the outside of masks of infected persons who had coughed in their mask. I'd worry about that if I were eating at a restaurant and repeatedly putting on & off my mask.
I normally wear a KN95 mask, but recently used a surgical mask for a day. I found it to feel like no mask at all. Air could find its way around the mask as I breathed in and out. I have done manual labor in a KN95 mask in 100F weather and found that I had to take mask breaks (in my car) to catch my breath and let the moisture (which impedes air flow) evaporate from the inside of the mask.