Will this read ambient air

Hi, no it won't read ambient air humidity. You would need a humidity meter for that. Here is an example: https://www.lowes.com/pd/General-Tools-Instruments-Digital-Multimeter/50102614. Hope this helps! Please give us a call at 844-841-9878 if you have further questions regarding your application. One of our product specialists will be more than happy to assist you. Thanks!