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

Author:
Leena, Parakkatt Parambil, Anil Kumar, Vasudevan, Dani, Kundan. K., Sombawne, Sunil. M., Murugavel, Palani, Pandithurai, Govindan
Source:
Toxicological and environmental chemistry 2017 v.99 no.4 pp. 652-664
ISSN:
1029-0486
Subject:
chemistry, coagulation, monsoon season, India
Abstract:
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.
Agid:
5636009