Abstract:

Life on the Earth exists because of atmosphere that surrounds it. As with the passage of time population increases and with this increases anthropogenic activities increases which is adversely affecting our atmosphere. That is why temperature of cities is soaring up. As our atmosphere is occupied by different gases, whose increase or decrease can substantially affects our environment. The major air pollutants, due to human activities, are carbon monoxide(𝐶𝑂), carbon dioxide (𝐶𝑂2), nitrogen dioxide (𝑁𝑂2), ozone (𝑂3), sulfur dioxide (𝑆𝑂2) and particulate matter (𝑃𝑀).Among these pollutants, 𝑁𝑂2 plays a big role as it can be produced due to road traffic and combustion of fossil fuels. In this paper, we investigated 𝑁𝑂2 in Pakistan troposphere through Sentinel-5 Precursor (S5-P) satellite. Data from the S5-P, with TROPO phosphoric Monitoring Instrument (TROPOMI) as payload, became available in July 2018, having spatial resolution nine times higher than that of OMI. S5-P launched by European Space Agency (ESA) with one-day revisit cycle, has the capability to sense all atmospheric gases. Our area of study is Pakistan. We processed S5-P datasets in Google Earth Engine (GEE) and produced results of four seasons, during 2018-2019, of 𝑁𝑂2. Different regions of Pakistan, which have excess 𝑁𝑂2in its troposphere, are also shown. This increase is supported by the fact that with time the increase in urban population causes dramatic negative effects on the atmosphere. Compared to traditional methods, this study will substantially increase the capability of the government and policy makers to take timely action on anthropogenic activities in mentioned cities, in order to mitigate emission of 𝑁𝑂2. Our findings illustrate the decrease of 𝑁𝑂2in summer, and surges in autumn and vice versa. In autumn Karachi, Sheikhupura, Raiwind, Lahore, Jamber, Faisalabad and Rawalpindi have highest concentration of 𝑁𝑂2 . In winter excess 𝑁𝑂2 spots over Karachi, Sheikhupura, Lahore, Raiwind, Jamber and Rawalpindi are detected. After winter, spring season shows further decrease in 𝑁𝑂2 concentration in which Karachi, Dera Ghazi Khan Sheikhupura, Rawalpindi and Lahore have highest 𝑁𝑂2 concentration and in summer 𝑁𝑂2 in Pakistan troposphere is further reduced to Sheikhupura, Raiwind and Jamber cities.