CONCENTRATION UNITS g,0上、 g g m3 0鸿 m3 g g 3 g =1 ppm m3 106cm3 100 mg g ppmCONCENTRATION UNITS g 103 mg  g m3  L m3  103 g m3 m3 106 cm3  g  106 g  1 ppm mg L g  m3  ppm mg L  g m3 g cm3 1