Identifying solid-aqueous phase transitions in atmospheric aerosols?I. Neutral-acidity solutions

Results and recommendations from an intercomparison of six Hygroscopicity-TDMA systems

“…We believe that the problem with system 2 during experiment 2 was not due to RH, but rather more to the sizing of the particles, most likely connected to a problem with flow in this individual case. Looking at the ammonium sulphate growth factors, particles at Dp = 30 nm agree well with literature values from Tang and Munkelwitz (1994) and Potukuchi and Wexler (1995) but as dry size increases, the growth factor decreased, the reverse of what can be expected due to the Kelvin effect.…”

Results and recommendations from an intercomparison of six Hygroscopicity-TDMA systems

“…We believe that the problem with system 2 during experiment 2 was not due to RH, but rather more to the sizing of the particles, most likely connected to a problem with flow in this individual case. Looking at the ammonium sulphate growth factors, particles at Dp = 30 nm agree well with literature values from Tang and Munkelwitz (1994) and Potukuchi and Wexler (1995) but as dry size increases, the growth factor decreased, the reverse of what can be expected due to the Kelvin effect.…”

Efflorescence Relative Humidity of Mixed Sodium Chloride and Sodium Sulfate Particles

“…Our theoretical prediction satisfactorily delineate experimentally observed variation in ERH as shown in Figure , where the experimentally measured ERH first decreases slightly with x β , reaches a weak minimum at x β = 0.1, and then increases. Interestingly, x β = 0.1 is the eutonic composition for MDRH obtained both experimentally 6 and theoretically . It should be noted that solute nucleation is a stochastic process caused by thermal fluctuation of a supersaturated state, and therefore the induction time for a huge number of particles represents only an average value …”

Surface Composition of Free Mixed NaCl/Na2SO4 Nanoscale Aerosols Probed by X-ray Photoelectron Spectroscopy

“…The consequence of the model derived by Ge et al is that mixed solid aerosols grown from droplets are composed of core–shell structures, in which the core consists of a pure salt, i.e., the salt with the higher relative efflorescence humidity, whereas the surface layer is composed of a mixtures of the two salts at a mixing ratio corresponding to the eutonic point of the system. For the NaCl/Na 2 SO 4 /H 2 O system the eutonic point lies approximately at a Na 2 SO 4 mole fraction of 10%. , Thus, in the model of Ge et al, the composition of the surface layer does not change with the initial mole fractions of the salts in the initial droplets. Clearly, the present findings are in contrast to this core–shell model suggested by Ge et al, as the chemical composition of the particle surface of nanosized aerosols is found to vary with the mole fractions in the initial droplets.…”

“…For the NaCl/Na 2 SO 4 /H 2 O system the eutonic point lies approximately at a Na 2 SO 4 mole fraction of 10%. 2,39 Thus, in the model of Ge et al, the composition of the surface layer does not change with the initial mole fractions of the salts in the initial droplets. Clearly, the present findings are in contrast to this core−shell model suggested by Ge et al, as the chemical composition of the particle surface of nanosized aerosols is found to vary with the mole fractions in the initial droplets.…”

Results and recommendations from an intercomparison of six Hygroscopicity-TDMA systems

“…We believe that the problem with system 2 during experiment 2 was not due to RH, but rather more to the sizing of the particles, most likely connected to a problem with flow in this individual case. Looking at the ammonium sulphate growth factors, particles at Dp = 30 nm agree well with literature values from Tang and Munkelwitz (1994) and Potukuchi and Wexler (1995) but as dry size increases, the growth factor decreased, the reverse of what can be expected due to the Kelvin effect.…”

Efflorescence Relative Humidity of Mixed Sodium Chloride and Sodium Sulfate Particles

“…Our theoretical prediction satisfactorily delineate experimentally observed variation in ERH as shown in Figure , where the experimentally measured ERH first decreases slightly with x β , reaches a weak minimum at x β = 0.1, and then increases. Interestingly, x β = 0.1 is the eutonic composition for MDRH obtained both experimentally 6 and theoretically . It should be noted that solute nucleation is a stochastic process caused by thermal fluctuation of a supersaturated state, and therefore the induction time for a huge number of particles represents only an average value …”

Surface Composition of Free Mixed NaCl/Na2SO4 Nanoscale Aerosols Probed by X-ray Photoelectron Spectroscopy

“…The consequence of the model derived by Ge et al is that mixed solid aerosols grown from droplets are composed of core–shell structures, in which the core consists of a pure salt, i.e., the salt with the higher relative efflorescence humidity, whereas the surface layer is composed of a mixtures of the two salts at a mixing ratio corresponding to the eutonic point of the system. For the NaCl/Na 2 SO 4 /H 2 O system the eutonic point lies approximately at a Na 2 SO 4 mole fraction of 10%. , Thus, in the model of Ge et al, the composition of the surface layer does not change with the initial mole fractions of the salts in the initial droplets. Clearly, the present findings are in contrast to this core–shell model suggested by Ge et al, as the chemical composition of the particle surface of nanosized aerosols is found to vary with the mole fractions in the initial droplets.…”

“…For the NaCl/Na 2 SO 4 /H 2 O system the eutonic point lies approximately at a Na 2 SO 4 mole fraction of 10%. 2,39 Thus, in the model of Ge et al, the composition of the surface layer does not change with the initial mole fractions of the salts in the initial droplets. Clearly, the present findings are in contrast to this core−shell model suggested by Ge et al, as the chemical composition of the particle surface of nanosized aerosols is found to vary with the mole fractions in the initial droplets.…”

Results and recommendations from an intercomparison of six Hygroscopicity-TDMA systems

“…We believe that the problem with system 2 during experiment 2 was not due to RH, but rather more to the sizing of the particles, most likely connected to a problem with flow in this individual case. Looking at the ammonium sulphate growth factors, particles at Dp = 30 nm agree well with literature values from Tang and Munkelwitz (1994) and Potukuchi and Wexler (1995) but as dry size increases, the growth factor decreased, the reverse of what can be expected due to the Kelvin effect.…”

Efflorescence Relative Humidity of Mixed Sodium Chloride and Sodium Sulfate Particles

“…Our theoretical prediction satisfactorily delineate experimentally observed variation in ERH as shown in Figure , where the experimentally measured ERH first decreases slightly with x β , reaches a weak minimum at x β = 0.1, and then increases. Interestingly, x β = 0.1 is the eutonic composition for MDRH obtained both experimentally 6 and theoretically . It should be noted that solute nucleation is a stochastic process caused by thermal fluctuation of a supersaturated state, and therefore the induction time for a huge number of particles represents only an average value …”

Surface Composition of Free Mixed NaCl/Na2SO4 Nanoscale Aerosols Probed by X-ray Photoelectron Spectroscopy

“…The consequence of the model derived by Ge et al is that mixed solid aerosols grown from droplets are composed of core–shell structures, in which the core consists of a pure salt, i.e., the salt with the higher relative efflorescence humidity, whereas the surface layer is composed of a mixtures of the two salts at a mixing ratio corresponding to the eutonic point of the system. For the NaCl/Na 2 SO 4 /H 2 O system the eutonic point lies approximately at a Na 2 SO 4 mole fraction of 10%. , Thus, in the model of Ge et al, the composition of the surface layer does not change with the initial mole fractions of the salts in the initial droplets. Clearly, the present findings are in contrast to this core–shell model suggested by Ge et al, as the chemical composition of the particle surface of nanosized aerosols is found to vary with the mole fractions in the initial droplets.…”

“…For the NaCl/Na 2 SO 4 /H 2 O system the eutonic point lies approximately at a Na 2 SO 4 mole fraction of 10%. 2,39 Thus, in the model of Ge et al, the composition of the surface layer does not change with the initial mole fractions of the salts in the initial droplets. Clearly, the present findings are in contrast to this core−shell model suggested by Ge et al, as the chemical composition of the particle surface of nanosized aerosols is found to vary with the mole fractions in the initial droplets.…”