Volume 5, No. 2, December 2005, Pages 127-140 PDF(449 KB)
Growth Properties of Sub-Micron Aerosols during Cold Season in India
D. M. Chate, P. C. S Devara
Indian Institute of Tropical Meteorology, Pune - 411 008, India
The growth properties of submicron aerosols were investigated on the basis of particle number size distributions measured in field experiments. An analysis of condensation sink, growth rate, concentration of condensable vapors and their source rate, and real and apparent nucleation rates as a function of particle sizes and their number concentrations in the submicron range are presented to quantify their effects during nucleation events. Higher number concentrations of newly formed particles of 0.013, 0.024, 0.075, and 0.133 μm around 0900 h indicate that photochemistry plays an important role in their formation, and that they grow principally by gas-to-particle conversion. The magnitudes of nucleation parameter η are indicative of the number concentration of newly formed particles by nucleation and their subsequent growth. The estimated value of η is around 10 nm for Aitken mode particles (0.013 and 0.024 μm) and 6 nm for accumulation mode particles (Dp > 0.1 μm). The formation rate of 0.013 and 0.024 μm particles is 2.33 cm3/s and of intermediate particles (0.075 and 0.133 μm) is 1.33 cm3/s. The growth rate of 0.013 and 0.024 μm particles is 0.3 and 1 nm/h and the rate for 0.075 and 0.133 μm particles is 8 and 21 nm/h, indicating that high formation rate and rapid growth are generally found in semi-urban and urban areas. These results may be of interest for future study of nucleation processes in different environments.
Nucleation event; Nucleated clusters; Condensable vapor; Fog–formation.