Since writing the previous blog entry (“What is my risk?”) I have encountered additional information to refine the risk calculation I outlined. I found a reference that provides a better value for the relative intensity of aerosol generation between the activities of talking and passive breathing: approximately 10X (compared to my placeholder value of 2). When this weighting is applied to the social interaction duration histogram, the critical exposure is reduced from four person-intensity-hours to three.
This does not seem like a large impact on critical exposure but the intensity level associated with talking now requires that all of those short interactions become shorter. If the critical exposure is 3 hours at level 1 (silent breathing in the same room), and talking is 10 times more intense, then an exposure of 0.3 hours (18 minutes) in conversation with an infectious person will deliver the critical dose of virus-laden aerosols. This suggests a limit of 15 minutes in any interaction with a stranger: the 15-minute rule.
Ever since the covid19 stay-at-home orders were relaxed for my state, I have been struggling to find some rules to guide me as we try to safely host small gatherings with qualified friends (today’s rules: outdoors, safe-distancing, maximum of two guests–who have also been in semi-quarantine).
I’d like to know “what is my risk?” after encountering N people in a day and spending a certain amount of time with each. In particular, if I interact with store clerks for a few minutes each, walk or bicycle past maybe a hundred people, or sit in a (sparse) movie theater with a few dozen others for two hours, what risks am I taking? I want to put it in relative terms with the risk I willingly accept when I drive a few miles for an everyday errand.
While in Sweden over the Christmas season, we noticed the popularity of candelabras placed in the windows of people’s homes. In these northern latitudes where the darkness of the winter night dominates the few hours of daylight, the distinctive chevron of lights provided a cheery greeting from the windows of the traditional-styled Swedish houses.
I thought it would be a nice accent to our own home with its not-so-traditional windows cut into a mansard roof. Surely Ikea would have such an item, with some suitable unpronounceable name, but I was disappointed. Perhaps I needed to shop the Ikea stores in Sweden rather than our Americanized versions of them.
Today was my last day of employment, and I will now be exchanging
the two major foci of my creative time.
My interests in photography and astronomy and art was always secondary to my full-time work as a color scientist, an occupation that has provided a long and fulfilling career.
But this particular outcome was something of a fluke; the
education I pursued was a hodge-podge of art, science, and engineering, and my
early career was filled with jobs at not-quite-successful entrepreneurial startups
that caused my dad to inquire where I was working next, because he wanted to
avoid investing there!
After years of fearing the consequences of corporate RIFs (“reduction in force”), aka layoffs, and having survived a dozen or more of them, I had finally reached the point where losing my job would have a lesser consequence. I had built up my savings in anticipation of some future retirement and was now working for the sheer pleasure of it.