Just How Many Different Substances Are in Atmospheric Air

What is a part-per-billion Imagine adding a drop of alcohol to a pool of water 6 ft deep x 12 ft wide x 18 fit long and stirring thoroughly. Alternatively, imagine a golf foursome compared to the world s total population.  

Graedel and P.J. Crutzen, Atmospheric Change An Earth System Perspective, Freeman, New York, 1993, p. 8. 

Seinfeld, Atmospheric Chemistry and Physics of Air Pollution, Wiley, New York, 1986, p. 8. 

Kebbekus and S. Mitra, Environmental Chemical Analysis, Blackie Academic and Professional, London, 1998, pp. 229-230. 

Graedel, D.T Hawkins, and L.D. Claxton, Atmospheric Chemical Compounds Sources, Occurrence, and Bioassay, Academic, Orlando, 1986. 

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