Units and measurements

Table 1: Units and measurements

QuantityUnitSymbol
Acidity/alkalinitypHpH
Areahectareha
square metrem2
square kilometrekm2
Concentrationgrams per litreg/L
parts per millionppm
parts per billionppb
parts per thousandppt
micrograms per cubic metreµg/m3
micrograms per decilitreµg/dL
tonnes per hectaret/ha
Electrical conductivitymicrosiemens per centimetreµS/cm
Lengthmicrometreµm
millimetremm
centimetrecm
metrem
kilometrekm
Massmicrogramµg
kilogramkg
tonnet
megatonneMt
gigatonneGt
PowermegawattMW
gigawattGW
kilowatt hourkWh
megawatt hourMWh
gigawatt hourGWh
Velocity and speedkilometres per hourkm/hr
Volumecubic metrem3
Volume (fluids)litreL
megalitreML
gigalitresGL
gigalitres per yearGL/y
Work and energypetajoulePJ
gigajoulesGJ
Other abbreviationscarbon dioxide equivalent unitsCO2-e
watts per square metreW/m2
degrees Celsius°C
tonnes per hectare per yeart/ha/yr

Table 2: Prefixes for the International System of Units (SI)

FractionPrefixSymbol
10–6microµ
103kilok
106megaM
109gigaG
1015petaP