Fig. 4: Various characteristic aerosol properties derived using size-resolved CCN, ACSM, and SMPS measurements on the day of the NPF and rapid particle growth event at Chennai.
a Particle number size distribution (normalized particle concentration in cm−3 plotted against diameter in nm). The individual aerosol number size spectra obtained from SMPS measurements plotted represent the time of the day before, during, and after the particle growth event. b Same as (a) but for CCN number size distribution derived for 0.15% effective supersaturation. c Same as (a) but for CCN number size distribution derived for 0.79% effective supersaturation. The markers in (b) and (c) represent the hygroscopicity parameter Kappa (κ), calculated from size-resolved CCN measurements for corresponding CCN number size distribution of 0.15% and 0.79% effective supersaturation, respectively. In panels (b) and (c), CCN number size distributions and κ are color coded by the time of the day. d The relation between critical dry diameter, Dcrit (nm), and effective supersaturation, estimated from size-resolved CCN measurements. The different marker shapes represent the time before (circle) and during (square) the particle growth event. These different markers are further color coded by κ calculated using the individual pairs of Dcrit (nm) and effective supersaturation on the day of the particle growth event. e Scatter plot between geometric median diameter of the mode fitted to the number size distributions measured by SMPS and the sulfate fraction measured by ACSM (N = 42 and R2 = 0.85). The dotted red line is a linear fit to the points.
