Anonymous wrote:http://www.nytimes.com/2012/02/26/realestate/greenwich-village-streetscapes-ivy-reviled-admired-and-lately-imitated.html?_r=0
"The extensive Oxford research indicates that the shade and rain protection provided by ivy creates a microclimate that moderates temperature change and the humidity fluctuation of a wall, with a corresponding decrease in freeze-thaw damage and the migration of salts within the masonry. Ivy was also found to reduce the attacks of airborne pollutants on surfaces."
Well, all I know is that it was removed from all the Harvard buildings when I was at the law school because the ivy was ripping out grout from the buildings in Harvard yard. A shame, really, but had to be done.