1/ Automobiles and Intake Fraction. Since cars are back in the news I thought I would retweet this model result I offered in early April 2020. I focused only on 1 micron particles & accounted for windows completely closed & cracked slightly open.

2/ Related air exchange rates were based on experimental results in literature for mid-sized sedans. Particle deposition to indoor surfaces were accounted for, as the surface to volume ratio in a 3 m3 cab is large. An important outcome was the intake fraction (IF)
3/ Here, IF is the number of particles (or virions in collective particles) inhaled by a receptor DIVIDED BY the number or particles (or virions in collective particles) emitted by an infector.
4/ Integrated over the two hour drive (in this example) the IF for all windows closed & a receptor at rest is 0.08 (8% of what comes out of the infectors respiratory system ends up in the respiratory system of the receptor). 8%! That is a very high intake factor.
5/ With additional ventilation from cracking a window open drops the IF to 0.012 (1.2%) still relatively high. Can get lower by opening more windows.
6/ An important point is that the intake fraction is not dependent on the amount emitted, and so the value is applicable to whatever the number of particles (or virions in particles) are being shed by an infector. Emission rate can be multiplied by IF to get at inhalation dose.
7/ In this analysis the IF ranges from approx 0.01 to 0.1. For a wide range of indoor spaces in buildings IF ranges from 0.0001 to 0.001. Intake fraction can be lowered w/ higher ventilation and/or better filtration (including portable HEPA filters), as well as UVGI for virions.
8/ Note that for large outdoor sources of pollution (think busy highways, power plants) with a receptor on the order of hundreds of meters to kilometers downwind the IF is typically on the order of 1 billionth to 1 trillionth.
9/ For the very special case of an inert pollutant (non-reactive and not removed by controls or surfaces) at steady-state IF = respiratory minute volume / volumetric flow of outdoor air through indoor space. IF = Qb/Qv
10/ I am working on a blog related to the use of intake fraction as a conceptual and quantitative tool for assessing indoor environments where exposure to SARS-CoV-2 may occur.
11/ Until then, I have posted some old handwritten course notes on intake fraction at https://t.co/iKuCeJKsrt

Apologies for sloppy writing. Enjoy the analogy of candles vs power plants in terms of inhalation of fine particles. Candles 👎. I know, different compositions.
12/ Also, if everyone in the vehicle wears masks the intake fraction is reduced on two fronts, less emissions from the infector and less inhalation of virus-laden particles by receptor. To be included in blog. Just do it!

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1. I find it remarkable that some medics and scientists aren’t raising their voices to make children as safe as possible. The comment about children being less infectious than adults is unsupported by evidence.


2. @c_drosten has talked about this extensively and @dgurdasani1 and @DrZoeHyde have repeatedly pointed out flaws in the studies which have purported to show this. Now for the other assertion: children are very rarely ill with COVID19.

3. Children seem to suffer less with acute illness, but we have no idea of the long-term impact of infection. We do know #LongCovid affects some children. @LongCovidKids now speaks for 1,500 children struggling with a wide range of long-term symptoms.

4. 1,500 children whose parents found a small campaign group. How many more are out there? We don’t know. ONS data suggests there might be many, but the issue hasn’t been studied sufficiently well or long enough for a definitive answer.

5. Some people have talked about #COVID19 being this generation’s Polio. According to US CDC, Polio resulted in inapparent infection in more than 99% of people. Severe disease occurred in a tiny fraction of those infected. Source:

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It was Ved Vyas who edited the eighteen thousand shlokas of Bhagwat. This book destroys all your sins. It has twelve parts which are like kalpvraksh.

In the first skandh, the importance of Vedvyas


and characters of Pandavas are described by the dialogues between Suutji and Shaunakji. Then there is the story of Parikshit.
Next there is a Brahm Narad dialogue describing the avtaar of Bhagwan. Then the characteristics of Puraan are mentioned.

It also discusses the evolution of universe.(
https://t.co/2aK1AZSC79 )

Next is the portrayal of Vidur and his dialogue with Maitreyji. Then there is a mention of Creation of universe by Brahma and the preachings of Sankhya by Kapil Muni.


In the next section we find the portrayal of Sati, Dhruv, Pruthu, and the story of ancient King, Bahirshi.
In the next section we find the character of King Priyavrat and his sons, different types of loks in this universe, and description of Narak. ( https://t.co/gmDTkLktKS )


In the sixth part we find the portrayal of Ajaamil ( https://t.co/LdVSSNspa2 ), Daksh and the birth of Marudgans( https://t.co/tecNidVckj )

In the seventh section we find the story of Prahlad and the description of Varnashram dharma. This section is based on karma vaasna.