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It's difficult to understand a threat we can't see. So, to visually illustrate the risk of coronavirus airborne transmission in real time, we used a military-grade infrared camera capable of detecting exhaled breath. @DDaltonBennett @thatdarongirl https://www.washingtonpost.com/investigations/2020/12/11/coronavirus-airborne-video-infrared-spread/?arc404=true
First thing to note, the footage is an underrepresentation. Those particles capable of carrying a virus spread farther and linger longer than the visible exhalation plume, which dissipates quickly to a level that the camera can't see.
The carbon dioxide that the camera can capture is used to map the partial path of these nearly invisible airborne particles - including droplets that can carry a virus and travel within our exhaled breath. Thanks to @MrErinO for modeling!
Here are two people talking inside without a mask. The models were in the same household. “You can see clearly how the exhaled air from one person reaches the other,” said Prof. Chemistry at CU-Boulder @jljcolorado while reviewing the footage.
The camera detects variations in infrared radiation that are not visible to the naked eye. It was fitted with a filter that specifically targets the infrared signature of CO2, the gas we exhale. A high-sensitivity digital filter is applied here to emphasize airflows.
Masks can limit the transmission of virus. “You have 100 droplets coming out from the mouth by the time they get past the mask, maybe there's only eighty...it's going to reduce to some degree the number of droplets coming out." - Rajat Mittal prof mech engineering at John Hopkins
Masks can limit the transmission of the virus but you don't "want to be behind a person whose mask is not fitting well, because if there are viruses, that's where the viruses are going to be. “ - @jljcolorado
Here's a person with a well-fitted KN95 mask. Most of the airflows actually leaking up.
When not wearing a mask, the droplets capable of transporting a virus project forward. Here's a woman laughing inside without a mask.
It's winter and people are moving indoors. The virus can build up inside when windows are closed and there isn't proper ventilation. And if it does, Virologist at Leicester Royal Infirmary Julian Tang said, "you can actually start to get concentrations that cause infection."
