If the Pixel has no ability to store data on an SD or microSD card, and it has neither Bluetooth nor Wifi as the product page seems to indicate, what is the purpose of plugging it into an AC adapter at all? Does it have some internal flash memory that it’s logging to?
Hard to say what the decision process was re: battery vs no battery (which is what i think you’re asking) but size/space, weight, cost and reliability were probably in the equation. These days, USB outlets are ubiquitous and relatively unobtrusive, so the space consideration (i.e., making it smaller) would become more compelling.
No I was talking about something else.
I figured it out, the only reason to connect it in the manner shown is to view the multicolor LED light’s color, green for healthy etc.
@alveolus as others have said above, power for the Pixel is provided through the USB plug on the end. USB power sources are everywhere as shown (not explained) in the photos in the product description.
As you correctly said there is no WiFi, bluetooth to output any data. However,
“The multi-colored led lights {part of the pixel} illuminate with the color of the AQI providing immediate and at a glance particulate (PM2.5) air quality readings.”