Could you eliminate or greatly minimize the COPD causing agents in the smoke?

Yes. Unfortunately, when it was tried with filtered cigarettes and low tar cigarettes, people smoked more cigarettes. So lower per cigarette exposure was offset by an increased total exposure.
No. (almost) the entire reason for COPD is located in the cigarette smoke...So the best way to minimize those agents is to stop delivering them to your lungs. That means to stop smoking. Yes, easier said than done, but it is essential.