@renevanbelzen I did not! We’re pretty clean prom pollutants (comparatively speaking) up where I live, so that’s surprising.
@jarrod It’s the sulphuric oxides, causing beautiful reds when sunlight has to pass through at dusk or dawn. Most is expelled by traffic nowadays, since industry had to clean up their act because of acid rain, far away in rain forests that were being destroyed. Levels are low enough to prevent acid rain, but it’s still there, across the globe.
@jarrod I suppose this how we might discovover civilizations on exoplanets, by the exhaust gasses in the atmosphere, both sulphuric and nitrous oxides, but mostly ozon, since that’s very shortlived and has to be replenished by living organisms. The SOx and NOx are evidence for industrialization (and volcanism).