We all know about how the old aersol cans used propelants that did a fair share in depleting the ozone layer a while back. We still use aersol cans now, even though we signed a contract stating we aren't supposed to. These aersol cans that we have used for a long time use a different propellant than the original ones. These contain hydrocarbons that contribute to the global warming problem. These cans also contain volotile organic compounds that remain floating in the lower levels of the ozone layer. These create a smog that induces asthma. Other products that do this are: hair spray, mouth wash, and perfumes.
topic and info at:http://www.popsci.com/earthtalk/article/2008-09/spraying-safely