I Am 76 Years Old And Have Been Asthmatic My

I am 76 years old and have been asthmatic my entire life. I am in remission for stage4 large b cell non-hodgkins lymphoma. Had chemo and radiation on my areas of chest and am lung damaged. I use inhaled steroids each day , budenside and brovanna. I seem to do poorly after flights although I take numerous cautions such as wearing a mask, bacterial hand solutions and many other.
I still get a pulmonary illness( bacterial) after half the flights.
Has anyone done research on this matter? If I have to stop flying I will but hate to have that conclusion and life restriction. However, living is better!