On the size distribution of water soluble particles in the atmosphere

Abstract

The size distribution of the mass concentration of some water soluble materials was measured by an impactor of three stages and membrane filters. It was found that about the half of the mass of sulfate and ammonium particles is in the range of Aitken nuclei. The size distribution of sulfate particles depends on the relative humidity of the air: more nuclei are in the Aitken size range if the relative humidity is smaller. The size distribution of chloride particles is rather different from that of sulfate and ammonium particles: only a small fraction of the total mass is in the Aitken range. Considering the stoichiometric proportion of the ammonium sulfate, it is an ammonium excess, which is greater in the case of smaller particles. It is not impossible that this ammonium excess is caused by the presence of ammonium hydroxide. It follows from these results that in the Aitken size range there are many sulfate and ammonium particles which may be active cloud nuclei even over the continents.

Chemical composition and size distribution of atmospheric aerosols over the Deccan Plateau, India

“…The size distributions of chloride and sodium were approximately log-normal and were in good agreement with mode B of the curve for total aerosol. This observation indicates that chloride and sodium are mostly present in the giant size range, which is in agreement with the reported findings by other investigators (Junge, 1963;Meszaros, 1968).…”

Particle-size distribution of inorganic water soluble ions in the venezuelan savannah atmosphere during burning and nonburning periods

“…Figure 4 show that particle size distributions of Na ÷ and C1-correlates very well at the various sites and during the different monitoring periods, indicating that both ions are mainly produced by the same source, most likely marine aerosols. These ions are mostly present in the coarse size range, which is in agreement with the findings of other authors (Junge, 1963;Mrsz~iros, 1968;Khemani et al, 1982;Savoie and Prospero, 1982).…”

Estimation of the Volume Fraction of Water Soluble Material in Submicron Aerosols in the Atmosphere

“…Further, data on the chemical composition of small particles around 0.02*m are at present insufficient compared with that of larger particles. Therefore, it is difficult as yet to make clear why these small particles showed a reduced value of e. Meszaros (1968) reported that the ratio of the mass of soluble material to that of insoluble material in particles in the size range of r* 0.14*m was greater than that for particles in the size range of r>0.14pm as shown in Fig. 5.…”

“…5 shows the values of * thus obtained as a function of dry radius rd. The values of soluble fraction obtained by Meszaros (1968) is also shown in the figure. The broken lines indicate the roughly estimated mean values as a function of particle radius.…”

“…It was found that the value of * increased from about 0.3 to 1.0 in December 1981 and (1) was obtained by Meszaros (1968) (converted into volume fraction from the ratio of mass of soluble material to that of insoluble material, assuming that the density of insoluble material is equal to that of soluble material). were different from each other, especially in the size range of grater than 0.04*m in radius.…”