Assessment of the Contribution of Rush Hour Fine Particles Levels to the Daily Particulate Matter Concentrations in Kigali

Particulate matter (PM) is the most dangerous form of air pollution as it causes serious health problems. In Kigali, most vehicles use petroleum and diesel which consequently contribute to toxic air pollution. These emissions are high because of rush-hour traffic, and exposure to these emissions could have serious effects on human health. This study focused on the contribution of rush hour fine particle levels to daily particulate matter (PM) concentrations. From July 2021 to May 2022, real-time data on fine particulate matter (PM ) were collected at two sites: Gacuriro and 2.5 the University of Rwanda-College of Science and Technology (UR CST). Seasonal, diurnal, weekly, and rush-hour variations in PM levels 2.5 were investigated using descriptive, correlation, and time series analysis. Peak PM concentrations were found at both sites during rush hour 2.5 2.5 periods, particularly between 06:00-08:00 and 18:00-20:00 h. The lowest PM levels were observed between 14:00 and 16:00 h. Across all seasons, weekends had lower PM levels than weekdays, with the lowest values 2.5 observed on Sundays. During rush hour, Vehicle exhaust emissions were recognized as a major cause of air pollution in Kigali. Focused measures are required, such as promoting cleaner fuels, supporting alternative transportation, and improving traffic management during rush hours. This study provides significant insights for effective air pollution mitigation techniques in cities affected by vehicle emissions, and it informs policymakers about the air pollution situation in Kigali, allowing them to make decisions to reduce air pollution.