Air Pollution
by Ana Beatriz
1. Could be visible or invisible, emit an odor or be odorless
2. While often considered a local issue, may have a range that is local, national, regional or global
3. Air pollution is often understood as an urban issue
4. Is the effect caused by concentrations of solids, liquids or gases in the air
5. There are many pollutants and they may occur naturally or from human activity
