1. What Do Concentrations Mean? How much is 20 parts per billion?

2. How much Ozone?  Low –0 to 20 ppb  Normal –30-50 ppb  High –> 60 ppb  Low –0 to 20 ppb  Normal –30-50 ppb  High –> 60 ppb

3. 350 ppm 350 molecules of carbon dioxide for every one million molecules of air mixture. Scientists would express this amount as 350 parts per million (ppm). 350 molecules of carbon dioxide for every one million molecules of air mixture. Scientists would express this amount as 350 parts per million (ppm).

4. or 350 ppmv  “by Volume”  Some things are measured by mass (ppmm)  Some gases occur in even smaller amounts.  Ozone is measured in parts per billion (ppbv)  Some gases are measured in parts per trillion! (pptv)  “by Volume”  Some things are measured by mass (ppmm)  Some gases occur in even smaller amounts.  Ozone is measured in parts per billion (ppbv)  Some gases are measured in parts per trillion! (pptv)

5. Parts per million  1 12 oz can of soda per 30 meter swimming pool.  1 3-oz chocolate bar/football field  1 bogey/3,500 golf tournaments  1 12 oz can of soda per 30 meter swimming pool.  1 3-oz chocolate bar/football field  1 bogey/3,500 golf tournaments

6. Parts per billion  1 square foot/36 square miles  1 bad apple/1,000,000 barrels of apples  1 pinch of salt/10 tons of potato chips  1 square foot/36 square miles  1 bad apple/1,000,000 barrels of apples  1 pinch of salt/10 tons of potato chips

7. Parts per trillion  1 square inch/250 square miles  1 postage stamp/an area the size of Dallas, Texas  1 flea/360,000,000 elephants!  1 square inch/250 square miles  1 postage stamp/an area the size of Dallas, Texas  1 flea/360,000,000 elephants!