TY - JOUR
T1 - The measurement of liquid water mass associated with collected hygroscopic particles
AU - Lee, Chung Te
AU - Hsu, Wen Chuan
N1 - Funding Information:
Acknowledgements*The authors would like to thank the National Science Council of the Republic of China on Taiwan for "nancially supporting this research under Contract No. NSC 86-2211-E-008-007. A helpful discussion from Professor James H. Vincent is greatly appreciated. We also thank one of the referees in particular for his insights and suggestions which led to the model described in Fig. 6.
PY - 2000/2
Y1 - 2000/2
N2 - This work presents the measurements of aerosol liquid water (LW) mass of NH4NO3, NaNO3, NH4HSO4, and NaCl using a newly developed method for the changing relative humidity (RH) at a stable room temperature. The target aerosol was generated by atomizing the 1.5% (wt/wt) solution of a known chemical and was subsequently collected on a Teflon filter. The four inorganic salts selected in this work were all hygroscopic, but their humidographs showed either with or without a hysteresis phenomenon. The NH4NO3 particles deliquesce at around 62% RH and re-crystallize at 32% RH with a gradual decline of LW mass. In contrast, the NaCl particles show a distinctive re-crystallization point at 47% RH and a deliquescent relative humidity (DRH) at around 76%. For NaNO3 and NH4HSO4 particles, no hysteresis effect was observed during the hydration and dehydration processes. A check on the evaporative loss of NH4NO3 particles showed no significant variation in the measurement of LW mass in 24 h. The comparison of the humidographs between sea salt and NaCl particles reveals that the amount of water uptake from sea salt is higher than that of the NaCl on a mol basis. The measured data and two humidographs from previous work were compared with a model calculation. A good agreement was found for most salts except for (NH4)2SO4 in the descending RH mode and NaCl in the ascending and descending RH modes. Finally, the effects of filter substrate on particles are discussed on the contact angle, particle agglomeration, and mass loading.
AB - This work presents the measurements of aerosol liquid water (LW) mass of NH4NO3, NaNO3, NH4HSO4, and NaCl using a newly developed method for the changing relative humidity (RH) at a stable room temperature. The target aerosol was generated by atomizing the 1.5% (wt/wt) solution of a known chemical and was subsequently collected on a Teflon filter. The four inorganic salts selected in this work were all hygroscopic, but their humidographs showed either with or without a hysteresis phenomenon. The NH4NO3 particles deliquesce at around 62% RH and re-crystallize at 32% RH with a gradual decline of LW mass. In contrast, the NaCl particles show a distinctive re-crystallization point at 47% RH and a deliquescent relative humidity (DRH) at around 76%. For NaNO3 and NH4HSO4 particles, no hysteresis effect was observed during the hydration and dehydration processes. A check on the evaporative loss of NH4NO3 particles showed no significant variation in the measurement of LW mass in 24 h. The comparison of the humidographs between sea salt and NaCl particles reveals that the amount of water uptake from sea salt is higher than that of the NaCl on a mol basis. The measured data and two humidographs from previous work were compared with a model calculation. A good agreement was found for most salts except for (NH4)2SO4 in the descending RH mode and NaCl in the ascending and descending RH modes. Finally, the effects of filter substrate on particles are discussed on the contact angle, particle agglomeration, and mass loading.
UR - http://www.scopus.com/inward/record.url?scp=0034142585&partnerID=8YFLogxK
U2 - 10.1016/S0021-8502(99)00048-8
DO - 10.1016/S0021-8502(99)00048-8
M3 - 期刊論文
AN - SCOPUS:0034142585
SN - 0021-8502
VL - 31
SP - 189
EP - 197
JO - Journal of Aerosol Science
JF - Journal of Aerosol Science
IS - 2
ER -