Impact of urban traffic congestion on emissions along a section of James Gichuru Road in Nairobi County, Kenya

Abstract

This study examined the impact of urban traffic congestion on air quality focusing on traffic volume and its emissions of carbon monoxide (CO), carbon dioxide (CO2), and particulate matter (PM2.5). Data collected revealed a strong correlation (r = 0.83) between traffic volume and emissions. The regression analysis indicated that each additional vehicle per hour resulted in a 0.07 unit increase in emissions, a statistically significant finding with a p-value of less than .001. During peak hours, traffic reached as high as 2000 vehicles per hour, contributing to alarming CO levels of 10 ppm and PM2.5 concentrations of 90 µg/m³. In contrast, off-peak hours averaged around 750 vehicles per hour, leading to significantly lower emissions. These findings underscored the considerable influence of traffic volume on air pollution, highlighting the urgent need for effective urban planning and traffic management to enhance air quality and public health in rapidly urbanizing areas. The study therefore recommended that traffic volumes, which rise during school hours, highlight the necessity for safe walking and biking paths to promote non-motorized transportation. It also suggested encouraging flexible work hours to reduce travel demands and enhancing community awareness as additional traffic calming measures. Furthermore, advocating for remote learning for students and educators could significantly decrease daily commutes to schools and the associated emissions. Collectively, these insights offer practical recommendations for addressing traffic congestion and improving air quality in urban areas.