Keeping tabs on the air quality in your home is impossible to do without some sort of device, but it's important for your family's health. Eve Room is a smart device that tracks the air quality, temperature, and humidity in your home and offers a report via the Eve app or directly on the device.
Place Eve Room in whichever room you'd like to receive measurements for (it's portable, so it can be moved at any time), and precise measurements and historical data can be viewed on the app. Once you check out the report, you can make adjustments to the air as needed (add an air purifier, make it warmer, open a window, etc.).
The 1.54" E-Ink display has support for Siri and remote access via HomePod and Apple TV. The rechargeable battery lasts for up to six weeks, and if you forget to charge it, the device switches to a limited measurement mode until the next full charge. You can also just permanently plug it in.
Buy Eve Room here for $100.