I always figured the increase in asthma cases in recent decades was fueled comparably to the increases in polio cases years ago.
A lot of asthma may be tied to the hyper-vaccination schedule, but back in the day, when they cleaned up the water systems (and not using public well pumps which wound up contributing cholera outbreaks), they also eliminated a lot of the polio virus that was commonly found in water.
Early introduction to small amounts of polio virus allowed folks to develop some immunity. However, when they cleaned up the water, polio cases exploded.
I suspect a lot of asthma comes from cleaning up indoor air. Humans, after all, spent tens of thousands of years warming themselves with indoor fires. In fact, if you recollect the Otzi the Iceman, his dissection showed that his lungs were heavily blackened.
So it’s likely that a little bit of pollution can be good for you.
I also suspect all the fragrances in EVERYTHING and the wide spread use or *air fresheners in plug ins or sprays, contributes to the rise in asthma cases and breathing problems.
My 3 daughters currently aged 45, 38 and 30 had one vax for all three.
My wife dummied up the paperwork for school but during an office visit they weighted my youngest daughter in another room and gave her an injection. I don’t know which one but 3 days later she had an asthma attack, which she never had before that.
She has had breathing issues ever since.