Q. How many sensors are there in a particular area?

A. You can find out how many sensors are in a given area using the PurpleAir map.

  1. Zoom in on your desired area on the map.
  2. Open the javascript console - click here for instructions on how to open the javascript console based on what browser you’re using.
  3. Once the javascript console is open, toward the bottom you will see ‘Fetching’ followed by a URL. Below this, you’ll find the numbers you’re looking for.


(this is obviously an old picture)

You’ll want to focus on the Updated number of total features - this will give you the total number of sensors in the area you’ve zoomed in on. The Indoor and Outdoor numbers provide the breakdown of the total into the types of sensors in that area.