| Popis: |
In this paper, variations of nitric oxide (NO), nitrogen dioxide (NO 2 ), oxides of nitrogen (NOx), ozone (O 3 ) and total oxidant (O X ) concentration in ambient air of Kathmandu valley are presented. O 3 behavior during weekdays, weekends and bandhas (general strike) is analyzed and the mechanism related to it is discussed. The increased NO 2 /O X ratio with increasing NOx concentration and the inverse relation between NOx and O 3 imply that the residual O 3 remaining after the NO–NO 2 –O 3 reaction chain controlled O 3 concentration in the valley atmosphere and the radical channel was likely to have a minor contribution. The higher positive correlation coefficient for O 3 variation during weekdays and bandhas, weekdays and weekends suggests common sources for the weekends and bandhas O 3 variation. The higher O 3 concentration during weekends and bandhas compared to weekdays was due to less destruction of O 3 . Enhanced reduction in traffic emission levels, enforcement of stringent emission standards within the valley and the surroundings may help to address the O 3 problem in the valley atmosphere. |
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