A study of the phase transition behavior of internally mixed ammonium sulfate - malonic acid aerosols

[摘要] This is a study into the phase transitions of aerosol composed of theternary system ammonium sulfate (AS) - malonic acid (MA) - water usinginfrared extinction spectroscopy. Twelve compositions were studied in bothdeliquescence and efflorescence mode experiments. The presence of a MAfraction, by dry mass, (f_MA) of 0.1 in an AS aerosol altered therelative humidity at which the phase transitions occur in an atmosphericallysignificant manner. For compositions with 0.25<f_MA<0.90, nodistinct ``deliquescence" was observed, contrary to the observed behavior inthe binary systems. The crystallization of both the MA and AS components issuppressed by the presence of the other component in the aerosol. Atf_MA=0.9, the crystallization relative humidity of MA was lowered fromRH=6% to less than 1%. Similarly, at f_MA=0.4, the AS componentdid not crystallize. The atmospheric implications of the results arediscussed.

[学科分类] 大气科学