Aerosols do good and bad contributions to global warming.
Aerosols can cool the surface of the Earth, because it reflects sunlight, which is good for Earth. Aerosols don't mean to do it though; it's an indirect thing that happens to be a positive thing for us!
Aerosols are such tiny particles, but such a big impact.
Aerosols are widely known for being extremely harmful, which is true, but only if there's an increase in carbon dioxide. Most of the time, this is caused from humans.
http://earthobservatory.nasa.gov/Features/SmokeClouds/smoke_clouds2.php
