the environment

My brainstorming about environment:
Car, hair dryer.
A car makes the air dirty, so it can be affected to fresh air. By doing so, many people cannot breath fresh air and their health get bad.
Hair dryer can increase the temperature of the earth, so it can be caused the earth.
Now, I ‘m concerning about the energy. When I don’t use the light, I turn off. When I turn on light, the energy becomes wasted.