Earlier quoted context omitted.
Just to point out how why this is a fairly nuanced topic, a shepherd may be breathing clean air but they're also exposed to UV radiation all day. They may have a higher morbidity due to increased skin cancer rates.
I'm no way an expert on the matter but by pure logic it's still amazes me how we survived (and evolved!) as a species for thousand of years without almost no shelter from direct sunlight and yet now (too much) sunlight exposure is seen as a cause of death. I know we lost almost all the body hair we used to have but still, we usually wear clothes when under the sun.
If we pushed back the reproductive age we'd eventually evolve to live longer (though would have more people dying without reproducing first). This experiment has been successfully shown in fruit flies.