If you're unsure, the best way to know is to:
* Check the owner's manual: This will specify if your vehicle was equipped with a cabin air filter and where it's located if so.
* Look for the filter location: The filter (if present) is typically located behind the glove box, under the dashboard, or near the blower motor. Searching online for "2002 Chrysler PT Cruiser cabin air filter location" with images may help you identify the possible spot.
If you can't find it and your manual doesn't mention it, it's highly likely your particular vehicle wasn't equipped with one from the factory.