You had better quit smoking.
Factories had better not their waste into the nature.
We should use less perfumes.
Sloganlar çevre ile ilgili bulabildim hava ile ilgili değil ama yinede yazayım istersen :
If you save the nature, you save yourself !
Trees is your future, protect your future !
If you destroy the nature, this words is coming for you : you will die.