There was a time when aerosol sprays were bad for the environment. It was an opoinion of researchers the the propelents used in aerosol sprays, at the time, were a contributing factor in the depletion of the ozone layer. In 1994 congress proposed legislature banning the use of CFC's in aerosol spay cans. Although it wasn't passed until 1996, many of the leading manufacturors in our industry responded immediately and began reformulating their products. Since that time aerosol hairsprays have been safe for the environment.
As far as performance goes, here are some things to consider when you're shopping for hairspray. Non-aerosol (pump) sprays are wet when applied to hair, making them good for people that like to work with their finished style while they are creating it. Because they go on wet, I don't usually recommend them to people with fine, humidity sensitive hair. They are a good working tool but I don't like to use them to set in a finished style.
Aerosol sprays go on dry and are perfect for locking in your finished look. This is the type of spray we use to finish special occasion hair during prom and wedding season. Because they are a dry product, they work well for people with fine, limp hair. So, there you have it, simple and sweet. Take this into consideration the next time you are shopping for spray and as always ask your haircare professional wich products are best for your hair.