Main content area

Evidence of new particle formation during post monsoon season over a high-altitude site of the Western Ghats, India

Leena, Parakkatt Parambil, Anil Kumar, Vasudevan, Dani, Kundan. K., Sombawne, Sunil. M., Murugavel, Palani, Pandithurai, Govindan
Toxicological and environmental chemistry 2017 v.99 no.4 pp. 652-664
chemistry, coagulation, monsoon season, India
The formation of ultrafine particles, their growth, and associated characteristic features has been studied during new particle formation events over a high-altitude station of the Western Ghats during the 2014 post-monsoon season. Most of the events were observed during noon time where particle bursts in the nucleation-mode size range from 5 to 25 nm followed by sustained growth in size. This phenomenon persists for ∼4–8 h with a growth rate of 1–2 nm h –¹. Peak concentrations of nucleation-mode particles during the event generally vary from 2300 to 5000 cm –³. The mean growth rate is 1.4 ± 0.42 nm h –¹, particle formation rate is 1.14 ± 0.22 cm –³ s –¹, coagulation sink is 0.35 ± 0.22 cm –³ s –¹, and condensational sink is 15.4 ± 2.6 × 10 –³ s –¹. All these values are comparable with earlier results from Indian region. Comparison of size-segregated particle number concentration during days of new particle formation events and those without new particle formation were carried out showing a distinct variation in nucleation and Aitken mode with least variability associated with the accumulation mode.