DAVIS, Calif. (KTXL) – The Centers for Disease Control and Prevention recommends people wear masks and adhere to social distancing to fight the spread of COVID-19.
But those precautions might not be enough to stop transmission through normal conversation, according to research coming out of the University of California, Davis.
Masks and keeping a 10-foot distance threshold are designed to protect against droplets let loose by a cough or sneeze, droplets that can be seen under the right lighting conditions.
UC Davis chemical engineering professor William Ristenpart studies microscopic aerosol particles produced in the lining of the lungs.
“You can’t see them with the naked eye but they are large enough to carry viruses including the virus responsible for COVID-19,” said Ristenpart.
And a cough or sneeze is not required for the virus to get airborne.
Just talking can put the virus in the air at about 10 particles per second, according to Ristenpart.
“So a 10-minute conversation leaves an invisible cloud of about 6,000 particles between you and your conversational partner,” explains Ristenpart.
Like a real cloud that stays airborne, virus-blasted aerosol particles float on currents of air, staying afloat for hours or more.
That means someone else can come along and get infected long after the both of you are done talking.
If you’re outside, the particles can dissipate quickly but if you’re inside they can travel from room to room.
Ristenpart compares the particle transfer to aroma particles from brownies his kids bake in the kitchen.
“They traveled on little currents of air all the way into my office here. So the same thing when someone speaks, those aerosol particles travel around just like that,” explains Ristenpart.
Ristenpart said these aerosol particles are so tiny they can actually squeeze through gaps of any masks and cause homemade masks to provide almost no protection at all.
“When you zoom in on them you can see it’s very easy for these very small 1-micron particles to make it through there,” said Ristenpart.
That’s not to say masks made of regular cloth are useless. Those masks can still protect against sneeze and cough droplets that can also carry the virus, according to Ristenpart.
Ristenpart told FOX40 that those masks are better than nothing, which is the same reasoning used by federal authorities in recommending the use of masks of any kind.
And those sneeze guards that are going up in retail stores also give limited protection.
“If you can smell what’s on the other side of the sneeze guard, then these 1-micron particles can make it around the sneeze guard as well,” said Ristenpart.
More studies have to be done to see how long viruses survive under different outdoor and indoor environmental conditions, according to Ristenpart.