I recently bought one of these air quality monitors and got to take it out for some measurements!

I'll share some findings in this thread.

CCing @CO2Guerrillas here, in case they would like to share.

A very quick intro:

This device measures:

-CO2 concentration
-relative humidity
-atmospheric pressure
-temperature

I spent ~$200 on Amazon. It pairs with your phone and you can watch data come in every minute or so.

https://t.co/aoXjyq8kdu
A lot of covid transmission is airborne. So, having clean air is a must for reducing transmission.

A great way to see how much clean air you are getting is to measure CO2 concentration.

Too high -> you could use more ventilation -> open some windows!
So, I walked around town and took some measurements.

Outdoor CO2 concentration should be about 400 ppm. I haven't calibrated my device yet, so I measured ~470. Close enough.

<800 is good for indoors. Something like 2000 is very bad.

https://t.co/oZAkVnr9ts
For a reference: inside my apartment I quickly get ~1000 ppm if I don't have windows open. Maybe ~1500 if things get bad.

If I crack some windows, even just barely, it gets down to ~600 ppm very quickly, and my heater can keep the apartment ~70 F no problem.
First stop: a small shop in Harvard Square. It is about 60 ft long, 20 ft wide, and usually has ~3 people in there.

CO2: 937 ppm.

Not great, not horrible. Surprisingly (to me), this place had the highest CO2 on my trip. It did have a purifier, which was nice.
Next stop: a very similar store, but it has less business and only ~1 person in there most of the time.

~700 ppm. Still good.
Plant shop around the corner, which was a bit larger in size, maybe 2-3x, but also maybe ~4 people in there on average.

650 ppm. Not bad!

Fun fact: this shop is 103 years old now.
Next stop was interesting: a paper store that was split into two completely separate rooms. Both the same size, and both had ~2 people in there. One had the AC blasting, the other had it off.

Basically the same results in both: 650-700 ppm
Next stop, a 2-floor CVS which is usually pretty busy. Picked a spot near the center of the store:

620 ppm. Still not bad!

The doors open often, and the AC was on.
Next stop was the Harvard bookstore.

560 ppm.

Very nice! Especially since my device reads ~470 outside.

Took this sample in the essential ideology section.
I was skeptical about the low values, so I went to another section (science books now).

520. Still good!

The whole store had their AC up very high. I could see many of the signs shaking due to airflow inside. I assume they were piping in outdoor air.
Overall, I was impressed with most places! I expected worse, but I also didn't go into any of the more dangerous areas, like restaurants (we still have indoor dining in Boston).
A side note: CO2 concentration is just a proxy for air quality. Not perfect, and many other things matter too.

Follow these people instead of me to get some real science:

@kprather88 @jljcolorado @ShellyMBoulder @CO2Guerrillas @jksmith34

More from Tech

(1) Some haters of #Cardano are not only bag holders but also imperative developers.

If you are an imperative programmers you know that Plutus is not the most intuitive -> (https://t.co/m3fzq7rJYb)

It is, however, intuitive for people with IT financial background, e.g. banks

(2)

IELE + k framework will be a real game changer because there will be DSLs (Domain Specific Languages) in any programming language supported by K framework. The only issue is that we need to wait for all this

(3) Good news is that the moment we get IELE integrated into Cardano, we get some popular langs. To my knowledge we should get from day one: Solidity and Rust, maybe others as well?

List of langs:
https://t.co/0uj1eBfrYj, some commits from many years ago..

@rv_inc ?

#Cardano

(a) Last but not least, marketing to people with Haskell, functional programming with experience and decision makers in banks is a tricky one, how do you market but not tell them you want to replace them. In the end one strategy is to pitch new markets, e.g. developing world

(b) As banks realize what is happening they maybe more inclined to join - not because they would like to but because they will have to - in such cases some development talent maybe re-routed to Plutus / Cardano / Algorand / Tezos

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A brief analysis and comparison of the CSS for Twitter's PWA vs Twitter's legacy desktop website. The difference is dramatic and I'll touch on some reasons why.

Legacy site *downloads* ~630 KB CSS per theme and writing direction.

6,769 rules
9,252 selectors
16.7k declarations
3,370 unique declarations
44 media queries
36 unique colors
50 unique background colors
46 unique font sizes
39 unique z-indices

https://t.co/qyl4Bt1i5x


PWA *incrementally generates* ~30 KB CSS that handles all themes and writing directions.

735 rules
740 selectors
757 declarations
730 unique declarations
0 media queries
11 unique colors
32 unique background colors
15 unique font sizes
7 unique z-indices

https://t.co/w7oNG5KUkJ


The legacy site's CSS is what happens when hundreds of people directly write CSS over many years. Specificity wars, redundancy, a house of cards that can't be fixed. The result is extremely inefficient and error-prone styling that punishes users and developers.

The PWA's CSS is generated on-demand by a JS framework that manages styles and outputs "atomic CSS". The framework can enforce strict constraints and perform optimisations, which is why the CSS is so much smaller and safer. Style conflicts and unbounded CSS growth are avoided.