Air quality sensor

Here are 2 nice ones I found in my research:

• Airthings:
  • https://www.amazon.com/Airthings-2930-Quality-Detection-Dashboard/dp/B07JB8QWH6 - Wave Plus looks good for $192.
• 2nd choice would be Purpleair: https://www2.purpleair.com/products/purpleair-zen for $300.