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CH3041
COMPOSITION OF AIR II
Gas concs. in unpolluted air at sea level:
Nitrogen 78.08  % (vol, dry air)
Oxygen 20.95  %  (mixing
Argon   0.93  %    ratios)
(Water   0.5 – 3.5 %)
Trace gases
Carbon dioxide 390   ppm
Neon 18.2 ppm
Helium 5.2 ppm
Methane 1.8 ppm
ppmi  x 10-4 = %i        pi = (%i / 100) x patm
    eg. 385ppm = 0.0385%
CO2 going up at 1.5ppm/year 390 is late 2009