MATHEMATISCHE UND GEOMETRISCHE ZEICHEN

ppm
ppb
ppt
ppq
ppqt

parts per million        (1 Millionstel)
parts per billion         (1 Milliardstel)
parts per trillion         (1 Billionstel)
parts per quadrillion (1 Billiardstel)
parts per quintillion   (1 Trillionstel)

0,000.1%
0,000.000.1 %
0,000.000.000.1%
0,000.000.000.000.1%
0,000.000.000.000.000.1%

10^-6
10^-9
10^-12
10^-15
10^-18

1g/t ;    1 mg/kg
1 mg/t; 1 µ/kg
1 µg /t; 1 ng/kg
1 ng/t;   1 pg/kg
1 pg/t;   1 fg/kg