Change in the concentration of pollutants in the air over the city of Lucknow, together with HYSPLIT4.0's trajectory and dispersion analysis

Abstract

This study examines the mean daily concentrations of oxides of carbon (CO), sulphur dioxide (SO₂), nitrogen dioxide (NO₂), and respirable suspended particles (RSPM-PM₁₀) at seven monitoring stations in Lucknow city: Hazratganj, Gomti Nagar, Talkatora, Aliganj, Sarai Mali Khan, Mahanagar, and Ansal TC. The data is collected between 2016 and 2022. Based on the analysis, it can be observed that at all locations, the yearly average concentration of RSPM varies between 148.74 and 323.05 µg m^-3, SO₂ between 7.11 and 8.94 µg m^-3, NO₂ between 23.52 and 31.86 µg m^-3, and CO between 27.38 and 33.89 µg m^-3. The study of seasonal variation reveals that the lowest recorded concentration of RSPM was 81.59 µg m^-3 during the monsoon, while the highest recorded concentration was 447.47 µg m^-3 during the post-monsoon. On the other hand, seasonal variations in SO₂ and NO₂ were found to be below the recommended requirements, ranging from 5.55 to 10.94 µg m^-3 and 20.23 to 38.40 µg m^-3, respectively. The COVID-19 lockout in 2020 caused the pollution level to somewhat decline, but it did not fall below the recommended limit for CO and RSPM. The Indian government has banned factories and implemented various measures within the city, but the levels of CO and PM₁₀ in Lucknow are not decreasing. The Trajectory and Dispersion study of the HYSPLIT4.0 model indicates that the wind, which blows from the northwest, carries pollutants from close by areas to maintain daily pollution levels above the Central Pollution Control Board's guidelines (i.e., 100 µg m^-3). This suggests that there is insufficient local pollution control. The results suggest that controlling particulate matter and carbon monoxide pollution in the city is a serious challenge and has an alarming situation as compared to SO₂ and NO₂ pollutants.