If you aren’t sure whether an application is running natively on your new Intel-based Mac or is operating in the Rosetta emulation environment, there are a couple of ways to check.
Highlight the application icon in the Finder.
Choose File> Get Info, or press Command-I.
Look for “Kind” under the General section. If it says “PowerPC,” it runs in Rosetta. If it says “Universal Binary,” it runs natively.

You can also use System Profiler to check all of your applications at once.
Choose Apple menu> About this Mac.
Click the More Info button.
Select Applications in the left hand column. It’s under the Software heading.
Once System Profiler creates a list of every application on your hard drive, look for the Kind column. It shows if each application is PowerPC or Universal Binary.
You can click the heading in the Kind column to sort your applications so all of the Universal Binaries are grouped together.