slantsixdan
=..=
I presume by "smog" Bewy means pollution that creates a visible haze rather than any specific chemical
Multiple things can cause visible haze. Particulates (smoke/soot) is one. Photochemical smog is another, and it doesn't just come out of tailpipes. It's the result of chemical reactions between sunlight and NOx (nitrogen oxides) and hydrocarbons. So yeah, this is a matter of specific chemicals.
I'll take his word for it that he's seeing more of that.
I won't. This isn't something that can be judged by declaring that what we think we see today is worse than what we think we remember we think we saw 35 years ago. It's also not something that can be judged by something OP got on ragebait talk radio or social media.
In the case of leaded gas, it (1) cuts out a rather nasty pollutant on its own, and (2) allows running catalytic converters, O2 sensors, and other emissions controls that create further pollution reduction, but won't do that on its own.
Even without a catalyst, the exhaust from an engine running on unleaded is significantly cleaner, both moment-to-moment and in the long run, than that same engine running on leaded. There's a mountain of data on this point, too.
So I could see a scenario where a switch to leaded gas on its own combined with an area ending up with more cars that do not have other emissions controls could end up with visible local smog levels rising even if the smog is less toxic.
A switch to unleaded fuel means less toxic pollution and less of it, even when some or all of the cars don't have catalysts. There are, however, more causes of smog and other kinds of air pollution, other than just motor vehicles. Wildfires (bushfires, in Australia), industrial emissions, etc. A thoughtless person goes "There! You see! It's not the cars, it's [whatever other source of air-crap]! Those do-gooders forced unleaded fuel on us fer no reazon!". A thoughtful person realizes that even if the air is still polluted, and even if it's worse than it was at some point in the past, if car exhausts hadn't been cleaned up, the air would be that much dirtier now.
Last edited:















