Read on Twitter
1/ Back to basics (focus on the source)
“If there is a pile of manure in a space, do not try to remove the odor by ventilation. Remove the pile of manure.” (Max von Pettenkofer, 1858.)
More ...
“If there is a pile of manure in a space, do not try to remove the odor by ventilation. Remove the pile of manure.” (Max von Pettenkofer, 1858.)
More ...
2/ When we think about transmission of COVID-19 by SARS-CoV-2 in aerosols we ought to think of Pettenkofer's words.
How do we remove the source from buildings?
It's difficult to remove sources entirely unless everyone who would have been in the building stays remote.
More
How do we remove the source from buildings?
It's difficult to remove sources entirely unless everyone who would have been in the building stays remote.
More
3/ But it is possible to reduce the magnitude of source emissions by various means, including testing to identify infectors (in a perfect world this can dramatically reduce sources in buildings). More.
4/ Source reduction can also occur by lowering occupant density (having some work or learn remotely). Halving the # of occupants lowers the potential for sources by a half.
More ..
More ..
5/ Source reduction can also include specific high source- emission activities no longer being allowed indoors, e.g., singing, heavy aerobic activities, etc.
More...
More...
6/ Source reduction also includes universal MASK wearing indoors, so that masks worn by infectors can capture a fair fraction of particles that contain SARS-CoV-2, thus reducing emissions.
More ...
More ...
7/ All of the aforementioned approaches go to the heart of Pettenkofer's point that the 1st rule of sustaining good indoor air quality is to get rid of sources, whether an infector emitting SARS-CoV-2, cigarette smoke, NOx from a gas burner, particles from candles, ..
More ....
More ....
8/ Of course, it is difficult to feel confident that the sources of SARS-CoV-2 in particles have been removed from building. We must try to reduce sources and source emissions as much as possible and layer on additional precautions to reduce the impacts of emissions.
More ...
More ...
9/ These include improved ventilation (greater outdoor air supply to indoor environment), improved filtration (including use of HEPA portable air cleaners), UV, greater physical distancing, less time indoors, activities outdoors when possible, & again, EVERYONE wearing masks!
