Publications by authors named "Manish Naja"

Article Synopsis
  • - The COVID-19 pandemic allowed researchers to examine how lockdowns affected air quality in the Asian Monsoon region, finding significant decreases in air pollutants like particulate matter and nitrogen dioxide during strict lockdowns.
  • - Satellite data showed a notable reduction in nitrogen dioxide across major cities, alongside reductions in other pollutants, while surface ozone levels increased due to changes in chemical reactions from lower nitrogen oxides.
  • - Some Asian countries showed positive economic growth during the pandemic despite lockdowns, indicating a possible link between reduced industrial activity and improved air quality, suggesting that emission reductions from traffic can enhance air quality in the region.
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This study attempts to examine the morphological, elemental and physical characteristics of PM over the Indian Himalayan Region (IHR) using FTIR and scanning electron microscopy-energy dispersive X-ray (SEM-EDX) analysis. The study aimed at source identification of PM by exploring the inorganic ions, organic functional groups, morphology and elemental characteristics. The pollution load of PM was estimated as 63 ± 22 μg m; 53 ± 16 μg m; 67 ± 26 μg m and 55 ± 11 μg m over Mohal-Kullu, Almora, Nainital and Darjeeling, respectively.

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The variability and trend of ozone (O) in the Upper troposphere and Lower Stratosphere (UTLS) over the Asian region needs to be accurately quantified. Ozone in the UTLS radiatively heats this region and cools the upper parts of the stratosphere. This results in an impact on relative humidity, static stability in the UTLS region and tropical tropopause temperature.

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Escalating emissions of several air pollutants over South Asia could play a detrimental role in the regional and global atmosphere. Therefore, it is necessary to investigate these emissions within the boundary layer and at higher heights utilizing satellite data that are more inclusionary, where limited in situ observations are available. Here, we utilize the Infrared Atmospheric Sounding Interferometer (IASI), Ozone Monitoring Instruments (OMI), TROPOspheric Monitoring Instrument (TROPOMI), and Global Ozone Monitoring Experiment (GOME-2) hyperspectral satellite data to assess the changes in emission sources during Indian lockdown with a primary focus on the tropospheric profiles of ozone and carbon monoxide (CO).

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Simultaneous observations (2014-2017) of organic carbon (OC) and elemental carbon (EC) are made over a high-altitude site (Nainital, 29.4°N, 79.5°E, 1958 m a.

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Surface ozone is mainly produced by photochemical reactions involving various anthropogenic pollutants, whose emissions are increasing rapidly in India due to fast-growing anthropogenic activities. This study estimates the losses of wheat and rice crop yields using surface ozone observations from a group of 17 sites, for the first time, covering different parts of India. We used the mean ozone for 7 h during the day (M7) and accumulated ozone over a threshold of 40 ppbv (AOT40) metrics for the calculation of crop losses for the northern, eastern, western and southern regions of India.

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