Genesis of New Particle Formation Events in a Semi-Urban Location in Eastern Himalayan Foothills

Autor: Barlin Das, Binita Pathak, Lakhima Chutia, Tamanna Subba, Pradip Kumar Bhuyan
Jazyk: angličtina
Rok vydání: 2023
Předmět:
Zdroj: Atmosphere, Vol 14, Iss 5, p 795 (2023)
Druh dokumentu: article
ISSN: 2073-4433
DOI: 10.3390/atmos14050795
Popis: New particle formation (NPF) events identified using scanning mobility particle sizer (SMPS) measurements, their subsequent growth and other characteristics over Dibrugarh, a semi-urban location in the eastern Himalayan foothills (EHF), during November–December 2016 are presented. The mean total number concentration of ultrafine aerosols was found to be high during morning and evening rush hours. The NPF occurrence frequency was found to be 14%. The temporal evolution of the hourly average aerosol number size distribution revealed that the nucleation burst occurred at a lower size spectrum, supporting the existence of NPF burst events. It continued to grow through coagulation loss and condensation sink with an average growth rate of 17.16 ± 12.29 nm/hr. The satellite-based observations showed a high concentration of the NPF precursors NO2, SO2, and HCHO during the NPF days. The backward air mass trajectories confirmed that the sources of emissions were confined within an area of radius ~100 km surrounding the observation site. These locally generated precursors and their associated photochemistry could be a probable reason for NPF occurrence at the study site.
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