Without the stratospheric ozone layer, life as we know it would not be possible. Further, the problem is not necessarily concentrated in the inner cities.
Ozone also attacks the cell membranes of plants, leading to stress.
However, any increase over and above the 'natural' level would add to any perceived problem with enhanced global warming. Absorbed by Ozone in the stratosphere. This is why the temperature of the stratosphere increases with increasing altitude. Also linked to eye cataracts. UV-B is also involved in a widely accepted link with eye cataracts.