Don’t have a definitive answer for you. Had a lobectomy 3/19 and like you recovering well. From what I can tell from my doctors is that the remaining part of the lung does it’s best to compensate for that part removed. My oncologist suggested breathing as deeply as possible and then blowing out that breath as forcefully as able. He suggests doing this several times daily. Am going to start doing this—did today and coughed, but Inthink it might help. Good luck to you.

@armstg- Good morning and welcome to Mayo Connect. I'm so happy that your recovery went well. You are now 2 years out. Have you gone to pulmonary rehab? It is the best way to regain as much breathing capacity as you can. I am guessing that you had a lobectomy. My first cancer, 22 years ago this October. It was also a 1b, NSCLC. I did not need chemo. As a matter of fact it wasn't recommended. What about you? Unfortunately lungs do nor regenerate but what is left of your lung will fill in. That doesn't mean that it will be like new but you will not have an empty space. Did you have a wedge or a lobectomy? What activities have you re-engaged in? Are you exercising? Are you using an inhaler? As the summer heats up and the humidity rises you might breathe with more difficulty so your pulmonolgist can prescribe one if you need it.
I'd like to share my blog with you that I have written about my long journey. https://my20yearscancer.com/
Please feel free to ask any questions that you might have.

@alamogal635 , @armstg- I have been doing some research so that all of us can see what happened inside our lungs before and after lung surgery. I wish that I had done this when I first had lug cancer but today's videos are great.
Please bear with anyone who sounds boring, it's still great info.

https://www.youtube.com/watch?v=kacMYexDgHg
what happens after lung segments are removed: https://www.youtube.com/watch?v=ZGE57Y_K8bc
https://www.youtube.com/watch?v=R6KAbpzKg38
https://www.youtube.com/watch?v=ad4f5AfCwls