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Indian Journal of Radio & Space Physics (IJRSP) >
IJRSP Vol.38 [2009] >
IJRSP Vol.38(6) [December 2009] >
| Title: | Number concentration characteristics of ultrafine aerosols (atmospheric nanoparticles / aitken nuclei) during 2008 over western Himalayan region, Kullu-Manali, India |
| Authors: | Sharma, Nand Lal
Kuniyal, J C
Singh, Mahavir
Negi, Ajay K
Singh, Kesar
Sharma, Priyanka |
| Keywords: | Ultrafine aerosol density
Nucleation bursts
Nanoparticle concentration
Aitken nuclei concentration |
| Issue Date: | Dec-2009 |
| Publisher: | CSIR |
| PACS No.: | 92.60.Mt |
| Abstract: |
The ultrafine
particles of three sizes 200, 30 and 10 A [20 nm (aitken mode), 3 nm, 1 nm
(nucleation mode / nano particles)] were monitored with water based condensation
particle counter during January-December 2008 at Mohal in Kullu-Manali area of
North western Himalayas. The results indicate
that diurnal pattern has faint bimodal structure with two peaks, one in morning
and other in evening but is not as distinct as found in plains. There is rather
constant particle density pattern consistent with vehicular movement from
morning till evening. This may also be due to abnormally large bursts of
particles (nucleation bursts) which are found to be more in summer than winter,
more during sunrise and less during afternoon. The weak nucleation bursts are
found to be frequent throughout the year than very strong nucleation bursts
which are mostly found during months of June, July and August. The monthly 24 h
average density gradually picks up from January, increases rapidly in summer
months and then decreases in winter. The density is more in summer than in
winter, a trend opposite to plains, may be due to development of warm thermal
layer on valley floor while cold layer developed along snowy hilltops in winter
leading to convection of fine particles up the slopes of valley during daytime.
The relatively more value in September and October is due to month long international
Dussehra festival in the valley and unexpected lower values in November and December
may be due to low local as well as tourist traffic flow; washout/rainout
effects; and higher inversion layer. The vehicular survey conducted agrees well
with diurnal, monthly as well as yearly averaged diurnal variation of fine
particles. The annual average of 24 h average value of ultrafine particles of
three size range is 18045±1212, 16811±2790, and 15407±3109 N cm-3, respectively.
The comparison with earlier results shows significant increase of ultrafine
particles indicating impact of vehicular increase in the region.
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| Page(s): | 326-337 |
| ISSN: | 0975-105X (Online); 0367-8393 (Print) |
| Source: | IJRSP Vol.38(6) [December 2009]
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