Just saw a show on PBS American Experience called "Cleaning the Air: The War on Smog
Very informative on the Smog problem in LA and why it was so different to most other parts in the country. The science behind the discovery of what the cause was and the science behind how they cleaned it up and the start of Nixon’s Clean Air Act.
‘Air Pollution Linked to Cancer-Causing Gene Changes in Nonsmokers’
‘For nonsmokers, air pollution may be an even greater risk factor for lung cancer than secondhand tobacco smoke, a study published in Nature suggests.’
https://www.nature.com/articles/s41586-025-09219-0
Some small cities have terrible air pollution problems, even today. Logan Utah sits in a bowl. During an inversion pollution is trapped under a warm layer of air. They have bad air days despite being far from any big city.
I moved to Pasadena in 1971 - I remember the terrible smog. Many days we couldn’t see the San Gabriel mountains. I remember seeing the limited visibility just looking down California boulevard. It seems ‘American experience’ will be a casualty of PBS cutbacks. https://www.nytimes.com/2025/08/27/arts/television/american-experience.html
We used to drive through Logan enroute to Bear Lake in the 70s. Do they still have Spudnuts?
Even growing up in Syracuse NY in the 50’s and 60’s. I remember driving into Syracuse from where we lived north of Syracuse on a clear sunny day and NOT being able to see the skyline because of smog. Then a few years after the clean air act you could see the skyline miles away. It was amazing how much cleaner the air became.
I grew up in Dayton Ohio…. A bowl where smog decided to rest! Noticeable on sunny days.
But my parents smoked, cars stunk in traffic so we didn’t smell the smog as much as we saw it.
Much better today because cars have cleaner exhaust, people smoke far less and the population of Dayton is half what it was when I was a kid.
A few years after the advent of PCV systems on cars, I began to realize just how much blow-by we always smelled when we were stopped in traffic. Obviously, the automotive emissions controls that came later were even more significant, but just adding PCV systems actually made a noticeable difference.
No. There are four and they are all in WA.
The oldest cars had draft tubes thst vented the crankcase vapors to the road. It made a distinctive black path down the middle of all roads.
Ah, too bad, we had a small shop in Ogden, but I was transferred out of Utah in 1976.
I remember them very clearly.
The first car I bought with a PCV system was a 1965 Rambler U purchased in 1965. The service manager explained to me that the PCV system was to control polution to prevent smog. I said smog wasn’t a problem in our area. He replied “Works pretty good, doesn’t it”?
I well remember the blow-by coming out the tube under the engine of earlier cars. I think even lawn mower engines have a system to control for emissions from the crankcase.
After putting some restrictions on cars in Central Paris, as well as installing more bike lanes, the progressive reduction in air pollution since 2007 has been impressive.
That show, like most American Experience shows, was very engaging social history. It focused on business, politics and science/engineering. It seemed to point to the introduction of the catalytic converter as a major turning point in the quest for healthy air quality: compared to earlier steps like PCV systems, much more expensive, and with much greater positive effect.
Around then, I bought a 1976 Honda Civic CVCC from a friend. Unlike just about everything else of its era, it met tailpipe standards without a catalytic converter. I didn’t know much about cars at the time, but I now think it had a much more complex system of pollution controls than would have been necessary if Honda had just used a converter.
It seems like Honda decided that the CVCC system cost less to use than a catalytic converter.
And after they switched to cats, they kept using carbs for several years to avoid paying license fees to Bosch for fuel injection, resulting in a rat’s nest of vacuum hoses.
I remember a former colleague had a 1989 Honda Accord
It was a pretty nice car . . .
Until you popped the hood and all you saw was untold miles of vacuum hoses
Who the heck wants to work on that?
I could kind of understand it on a late 1970s car
But there was absolutely no excuse for it on a 1989 Accord, imo
My buddy drug a 1984(?) out of a field a few years back and towed it to my house so I could help him bring it back to life, after we got it running and drove it around a little bit, one of then 1st thing we did was to remove those crazy 100 vacuum lines and cvcc carb and replace it with an old school Webber carb, big difference in drivability…
Next up will be a later model (1993) engine and trans swap with fuel injection, gonna build the engine and re-gear (close ratio gear set) the transmission…
At 1st though he asked me to help (he’d watch me) him rebuild that cvcc carb, I said holler at me when you need something simple rebuilt like a transmission!!.. 
That is why the Webber was installed… lol
5:51 pm cst
Computerized emission controls would replace the snake pit of hoses by the early to late 1990s.
