Having a few internal and external sensors for various gasses could work, but it’s a surprisingly difficult problem.
My experience (and my nose) strongly disagrees with this assertion. YMMV.
The urban-vs-rural divide in my area is shockingly detectable just by the smell of combustion byproducts alone.
> you aren’t tracking [wind direction]
Who says I'm not? Tall flagpoles make for nice, ubiquitous windsocks. I wouldn't use it to land a plane, but for this purpose it works just fine.
And yes, it's absolutely a hard problem. Just look at all the ink I've spilled...
The human nose (especially mine) is still a remarkable chemical sensor, with only a few blind spots. In practice the major blind spots, namely CO, correlate well with detectable combustion byproducts. I appreciate your concern, but you worry for no good reason!
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I'll share one final trick, which should be pretty obvious: avoid sucking in the packet of air a bunch of cars (or one diesel truck) just accelerated through. In practice, usually this means turning on recirculate when stopping behind a line of cars, and then waiting to turn off recirculate until a short distance after going through the light.
Just to preempt the seemingly-inevitable negativity reflex: if you don't believe such hyper-local variations in pollution make a big difference, I guess you've never cycled before. ;)
To good air and good health! Cheers
https://en.wikipedia.org/wiki/Olfactory_fatigue
Urban/suburban areas provide a different variety of smells which is easy to confuse with overall toxicity levels. Chemical sensors will sometimes line up with your expectations and other times be very different.
Living outside the city, I'm not constantly fatigued to its odors. So that's not a factor.
But more to my original point, it disproves the "wind > location" idea (in my geography), since odor acts as a tracer for packets of air coming from the city.
I wish I could calm your anxiety, but on the bright side I am truly touched by your outpouring of concern for my respiratory well-being! Thank you, kind stranger.
