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<p>The present study is carried out to explain the presence of large concentrations of SO<sub>2</sub> in atmosphere of Pakistan during June, 2011. Large volcanic eruptions are a major source of greenhouse and trace gases. The eruption of Mount Nabro in June, 2011 injected large amount of SO<sub>2 </sub>into stratosphere. Nabro volcanic eruption generated a layer of sulfate aerosols, which resided in stratosphere for months. The total amount of SO<sub>2 </sub>that was injected into the atmosphere was estimated to be 1.3-2.0 Tg. Data products of Global Ozone Monitoring Experiment (GOME-2), Ozone Monitoring Instrument (OMI) and Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) were used to study SO<sub>2</sub> concentrations and plume movement over Pakistan. HYSPLIT backward trajectory model is utilized to study the origin of SO<sub>2</sub> plume. The study confirms that SO<sub>2</sub> plume originated from Nabro volcanic eruption and caused significant atmospheric perturbations and affected the air quality of Pakistan. SO<sub>2</sub> emissions from volcanic eruptions can pose serious hazard to population as well as global climate.</p>
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