Using anodized titanium surface as a building skin

I am an architect in the office of Frank Gehry. We have been planning a building using anodized colored (pink and gold) titanium panels in rural Spain for many years. Six months ago, we erected a mockup at the site. Dirt/dust particles collected from the panel surface has been shown to contain silica and sulphates. The client has gotten "cold feet" due to the fear of these compounds altering the protective oxide film of the titanium over time and hence discoloring the panel surface. Can anyone comment on the likelihood of discoloration and methods to prevent it? At present, the dirt, dust, and water stains remove easily with cloth and water.

Andrew,

I do not think either silica or sulphates would damage the titanium oxide layer. We anodize parts for implants and they are stable in the body. I would refer you to Titanium.org on the internet. I would be more concerned about wind abrasion of the oxide layer.