Abstract:
The study examines spatial and temporal variations on the seasonal scale for the variability of four primary atmospheric pollutants, Nitrogen Dioxide (NO2), Carbon Monoxide (CO), Sulfur Dioxide (SO2), Methane (CH4), and Ozone (O3) in Islamabad based on the satellite data of high spatial resolution by the Sentinel-5P TROPOMI sensor. Using observations of remote sensing and matching it with Capital Development Authority (CDA) zonal boundaries, the study gives an account of air quality on a zonewise basis among the 5 zones of the city. Results indicate the most pollution-intensive zone as Zone IV because the levels of all pollutants have remained high all the time, especially in the seasons of smog (November to February). This can be attributed to the heavy traffic, manufacturing, and winter inversions. On the contrary, the air quality was relatively good in Zones II and V, which had a lower urban density and substantially more vegetation. The seasonal changes showed more concentration of NO2, CO, CH4, and SO2 in months of smog and O3 in the months without smog, since it was formed through photochemical reactions. The annual averages of Zone IV emitted more than half of the total amount of SO2, NO2, CH4, and CO in the territory of the city. The NEQS in Pakistan was used to compare, and it was found that CO and O2 exceeded the limits, which are allowed, whereas NO2 and SO2 were within the safe range. However, large quantities are a cause of concern to the environment. This study highlights the relevance of satellite remote sensing-based monitoring on the urban air quality and, hence, offers important information on localized pollution control and evidence-based policy making in Islamabad
