| A | B |
|---|
| Acid Precipitation | When rain water has a pH of 5.2 or lower. |
| Air Pollutants | Air borne particles and gasses that in occur in high enough concentrations to cause harm to organisms or damage the environment. |
| Mixing Depth | The vertical distance between the Earth’s surface and the convection movement upward. |
| Particulate Matter | General term for solid and/or liquid particles in the atmosphere. |
| Photochemical Reactions | Reactions that are caused by primary pollutants and sunlight. |
| Primary Pollutants | A pollutant emitted by a source that is identifiable. |
| Secondary Pollutants | A pollutant that is caused by chemical changes in the atmosphere from a primary source. |
| Smog | Air pollution that is commonly found in urban or industrial areas. |
| Temperature Inversions | When the atmosphere is very stable and does not allow any vertical mixing, because of warm air over cool air. |
