You're absolutely right to look into this — YouTube ads showing on mobile apps (especially games and kid content) can burn your budget fast with poor quality traffic, high bounce rates, and low intent.
Here's exactly how to exclude low-quality mobile app inventory from your YouTube campaigns in Google Ads:
Option 1: Exclude mobile app categories manually
Go to your Google Ads account
Navigate to your YouTube campaign → Placements → Exclusions
Click "Edit Exclusions"
Select "App Categories" under "Placements"
Choose to exclude:
This will block your ads from appearing in all mobile apps (Android & iOS), while keeping them on mobile web and desktop.
Option 2: Exclude by placement URL pattern (advanced method)
For older accounts or additional control:
Go to campaign or ad group level
Click on Placements → Exclusions
Use this domain-style exclusion: adsenseformobileapps.com
Note: This used to be a universal method, but Google has deprecated some of this functionality — still worth testing in some accounts.
Bonus Tip: Use device targeting filters
If app traffic is consistently poor, you can also:
Go to Devices under your campaign settings
Bid lower or exclude tablets/smartphones if needed
Or create a desktop-only campaign (though this limits reach)
Pro Tip: Monitor placements
After a few days of spending:
Go to Placements → Where ads showed
Export and review poor performers (e.g., kids’ apps, random games)
Manually add those as exclusions