Speakers - 2026

Title: Evaluating the concentration of air pollutants in different land-use patterns in nairobi

Abstract

Air Pollution has been identified as one of the major environmental risk factors affecting health.  The increase in population has also led to a transformation of the city's land-use patterns, which may influence spatial variations in air quality. This study evaluates the concentration of key air pollutants (CO, NO2, SO2, O3, and PM2.5) across four dominant land-use classes: residential, commercial, industrial, and green spaces. Satellite-derived data from gaseous pollutants were obtained from the Sentinel-5 Precursor satellite. These datasets were accessed through Google Earth Engine for the period 2020 - 2024. The PM2.5 data was obtained from ground monitoring stations using low-cost sensors for 2023-2024.

Pollutant observations were spatially assigned to land-use classes using GIS overlay techniques. Air Quality Index (AQI) values were computed for each pollutant and aggregated using a weighted approach. A one-sample t-test was conducted to assess whether the mean of each pollutant in Nairobi is significantly different from established guideline values at a 5% significance level. Results indicate that air quality in residential, industrial and green park areas fell in the unhealthy for sensitive groups category with AQI ranging from 113.68 to 113.97. In commercial areas, the AQI was slightly elevated at 115.45, which emanates from their heavy traffic and business activities, therefore emitting elevated concentrations of pollutants like PM2.5, NO2 and CO. The fitting effect of the model was not significant above the acceptable limits for CO, NO2 and SO2, while PM2.5 and O3 are significantly above the acceptable limits, indicating serious air quality concerns in the different land use patterns. Therefore, there is a need to develop stricter pollution control strategies to reduce the AQI levels. There is a need for institutions to invest in gaseous monitoring sensors to monitor real-time pollutant concentration for specified areas, and further research on pollutant concentration levels in Nairobi.

Keywords: Air quality, air pollution, air quality index, land use patterns, concentration, Nairobi.