The epicenter of the odor is where Market Street meets Third Street and Kearny. You can often see passersby making faces and holding their noses, especially the tourists.
I fear locals are aware the odor is there and have either become acclimated to the nasty smell or they just know they have to grin and bear it, although I am not sure about the grin part.
The best way to think of the odor is to think about coming across a homeless man who hasn't had a shower since the Bill Clinton administration and is still wearing what is left of clothes he put on during that period--and hasn't wiped his ass since that period.
I have never smelt such a foul odor anywhere, in any other city.
I suspect it's government regulations that are somehow behind the stink.
I'm told by one merchant that because of the phony water "shortage," shopkeepers are not allowed to clean the sidewalks with power water sprays unless the water is recycled water. Most of the actual physical sidewalks do look exceptionally dirty. I will see an occasional sidewalk being watered down but the sightings are few and far between.
Who really knows what is behind it? The city certainly isn't doing anything about it.
Fortunately, right now it is the heavy fog season, so the cold, the fog and the strong breeze make the odor less of a problem until the sun burns the fog off around noon. The stink rises with the clear sun.
In traveling various cities, I have come to appreciate mayors of Irish ancestry (#IrishMayorsMatter), they are crony but at least they keep their cities clean. Chicago's Mayor Daley was as crony as you could get but he had beautiful flowers planted in downtown Chicago. (Of course, it turned out his brother was somehow linked to the flower provider.)
In New York City, when the Jewish Mayor Ed Koch was in charge, he made a big stink (pun intended) and called loudly and often for residents to clean up after their dogs. And residents did. When Koch was mayor, you rarely saw a dog dump. Koch was followed by Mayor David Dinkins and because of some sort of disrespect for him or something, the dog dumps came back. I named them Dinkin's Dumps.
In San Francisco, the current mayor is Ed Lee. He is of Chinese ancestry.
He appears to be doing a fairly good job of getting building going in the city, despite objections from the wacko left. It is an exciting time to live in the city. But there is that stink.
The wikiepedia picture of Lee seems to show him posing through the stink.
I hope he gets the stink problem solved. I would hate to have to start calling him Stinky Lee.