Instant disproof
An interesting hypothesis: The east side of cities is poor because prevailing winds carry industrial pollution eastward.
Could be valid for NY and Paris, which are the examples mentioned, but I can immediately offer a perfect counterexample. Ponca. Refineries covered the south edge of town and made a BIG stink. Okla has constant prevailing wind from the southwest, so the smelliest parts of town are toward the northeast. Where is the richer part of town? Toward the northeast.
The poor parts of older cities were located close to the industries where poor people worked. In other words, the poor were close to the SOURCE of the pollution regardless of wind, not close to the OUTFLOW of the pollution.
I'm more inclined (literally) to use
Sailer's rule. High land = high status. At least in the central third of the US, between the Miss and the Rockies, altitude steadily increases westward. The west side of town is usually higher than the east, thus usually richer than the east. Secondarily: Because rivers gradually work their way downward, rivers prefer to meander eastward, which means the flood plain (former river) tends to be between the river and the west-high-land. Industries began in the flood plain to get close to hydropower and shipping. Settlement then advanced westward and uphill, not across the river. The up=west gradient would also be true east of the Appalachians, but not between the Miss and the App. In that zone downward is less predictable. Often but not always it's northward toward the lakes.
Labels: Heimatkunde