. . " Mole concentration means number of moles per unit volume, also called \"molarity\", and is used in the construction mole_concentration_of_X_in_Y, where X is a material constituent of Y. A chemical species denoted by X may be described by a single term such as 'nitrogen' or a phrase such as 'nox_expressed_as_nitrogen'. The chemical symbol for atomic nitrogen is N." . "Climate and Forecast (CF)" . "mole concentration of atomic nitrogen in air" . .