Evaluating the spatio-temporal variation of air quality in Kampala City

Abstract

This study investigated the spatio-temporal variation of air quality in Kampala City in the areas of Kawempe, Nakawa, Makindye, Lubaga and Central. The atmosphere around the earth contains an essential element, Oxygen that makes our interaction with it of utmost importance to human existence on the planet. However, as a result of population increase and urbanization, human activities greatly contribute to pollution of our atmosphere thereby threatening public health and safety. And according to World Health Organization this threat stands at some 6.7 million premature deaths annually (WHO, 2019). The purpose of the study was to identify the time of the day with the highest PM2.5 concentrations within a period of 24 hours and comparing the value with the world health organization’s safe value of 15µgm-3 with some specific objective of; (1) Identifying the sources of air pollution and their contribution to air quality in the urban Centre. (2) Assessing the temporal variation of air quality in the urban Centre, including the concentration of PM2.5. (3) Evaluating the impact of weather conditions and other environmental factors on air quality in the urban Centre. (4) Providing recommendations for improving air quality in the urban Centre. This would help the decision making body to make an informed decision on pollution mitigation since Kampala is one of the cities highly affected by pollutants. Data was obtained from KCCA clarity node solar powered sensor. The average hourly value of the data for the five different stations was obtained showing two peak values of PM2.5 concentration of 58µgm-3 which exceeds the world health organization’s safe value of 15µgm-3. The two peak values were observed in the morning (1000hrs to 1200hrs) and evening time of (2000hrs to 2100hrs) ranging from 72.9µgm-3 to 73.2µgm-3. Unhealthy air quality was obtained as evidenced by PM2.5 concentration exceeding the WHO target safe level even during the time of less traffic and economic activity in Kampala City Therefore, the initiative to improve air quality cannot be confined to only KCCA hence the need for multi sectoral collaboration to achieve the mandate of the KCCA clean air action plan.