TITLE:
Evaluating the Concentration of Air Pollutants in Different Land-Use Patterns in Nairobi
AUTHORS:
Maryvine Nyanchoka, Ezekiel Ndunda, Esther Kitur, Kanyiva Muindi, Esther Judith
KEYWORDS:
Air Quality, Air Pollution, Air Quality Index, Land Use Patterns, Concentration, Nairobi
JOURNAL NAME:
Open Journal of Air Pollution,
Vol.15 No.2,
June
30,
2026
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 for 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 were 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 the different land-use classes is moderate, with commercial areas being slightly elevated, having a weighted AQI of 91.50. Residential, industrial, and green park areas are also in the moderate category, with the weighted AQI ranging from 89.40 to 88.35. In commercial areas, the slightly elevated AQI can be attributed to 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 AQI levels. Institutions need to invest in gaseous monitoring sensors to monitor real-time pollutant concentrations for specified areas, and further research on pollutant concentration levels in green spaces around the city.