The Long Wall which Long Wall Street is named for always has a light line of white sand at its base, and nearly always has ongoing masonry works to repair it.
These pictures are taken at another Oxford road junction.
On the eastern edge of Oxford another set of traffic lights, at the junction of Cowley Road and Between Towns Road, again causes stationary traffic.
The local limestone is not very hard, and is constantly eroded, with the damage to the mortar being worse than that to the stone.
The damage is worst at ground level up to one metre.
The damage is worst near the ground and is caused by acidic exhaust fumes.
Here all the lichen has been killed and the brick looks as though it has been cleaned with brick acid.
We know that breathing in small particles from diesel exhaust is dangerous, as the particle size is small enough to pass deep into the lungs. The pattern of the effect on the walls shows that the concentration is particularly strong under one metre in height. There are two primary schools, one on either side of this junction.
Iffley Village Oxford Rag Stone
The quality of Oxford stone can be pretty shaky, and the stone that was used for field and road boundary walls was presumably of lower quality than that used for houses as good quality stone is scarce on the clay. This wall in Iffley is a charming example, but note what is happening to the bottom metre.
Who should we be claiming financial damages from? Shell? BP? Exxon?