I am agree with you, as the Healthy lifestyle is the best way to avoid all kinds of problems. While as you mentioned:
1) clean water - get enough
2) mild exercise - easy does it
3) enough rest and sleep - without the tv on
4) eat better - research and do
are great ways to avoid your health be affected by the air cleaning quality. On a further step, air purifiers are needed to solve the breathing problems that you already have.