Ozone is not a problem of the past. Some people will say that the ozone hole has repaired itself, since CFCs were banned by the Montreal Protocol. While it is true that most ozone depleting chemicals are banned, and it's true the hole is shrinking, experts estimate that ozone levels in the Antarctic will not return to pre-1980 levels until after 2050. Also, many people are unaware of the double-sidedness of ozone—ozone, when it is in the lower atmosphere (the troposphere), is a harmful component of smog, which reduces breathing air quality. Ozone is only good when it is in the ozone layer.
Source: http://ozonewatch.gsfc.nasa.gov/
