Seasonal Variability between Major Air Pollutants and Physical Landscapes in the Greater Nairobi Metropolitan Region

Abstract. Satellite data is crucial in regions lacking ground monitoring stations and is helpful in identifying areas likely to have high concentrations of pollutants harmful to human health. As these cities expand and grow, the quality of life and conditions will also be changing. The study seeks to determine the correlation between land surface temperature (LST), elevation, enhanced vegetation index (EVI), rainfall, particulate matter (PM_2.5), nitrogen dioxide (NO₂) and ozone (O₃) both day and night during the months of October–December in 2019 and 2024, January-February, June-August in the year 2020 and 2025. The results indicate a varied strength in relationship between variables in each season, both day and night. During the day the highest negative correlation is obtained between elevation and carbon monoxide, while during the night the highest negative correlation is obtained between elevation and LST in all periods analysed. In all seasons and both day and night-time, all counties have a mean PM_2.5 higher than the recommended WHO annual guidelines. Results from this study indicate the spatial and temporal variations of aerosols over different conditions and are crucial for the development of mitigation strategies that will result in improved quality of life.