What do you worry about more: Getting exercise, eating vegetables, or the air you breathe?
While most things that clearly improve health are well known, one is insanely underrated: Fixing your air. I suspect this is often the most effective health intervention, period. Nothing else is so important while also being so easy to address.
Let’s do a sanity check: Take the four biggest countries in the world and compare how many people died from various causes in 2019.