Investigation of Traffic-Related Air Pollution at Major Road Intersections in Abuja, FCT

This study investigates the concentrations of traffic-related air pollutants including carbon monoxide, nitrogen dioxide, and fine particulate matter at major road intersections in Abuja, Federal Capital Territory. Urban vehicular emissions are a growing public health concern in Nigeria's capital, where rapid motorisation, an ageing vehicle fleet, and persistent traffic congestion combine to create elevated pollution exposures for commuters, roadside traders, and pedestrians. Monitoring was conducted at eight signalised intersections in high-traffic corridors including the Berger, Area 1, and Maitama junctions during peak morning, midday, and evening periods on both weekdays and a weekend. Pollutant concentrations were measured using calibrated electrochemical and optical sensors mounted at breathing zone height. Vehicle counts and fleet composition data were collected concurrently. Results show that carbon monoxide concentrations at peak traffic hours exceed the one-hour WHO guideline of thirty-five milligrams per cubic metre at six of eight monitored intersections, with highest values at the Berger intersection where congestion persists for the longest duration. PM2.5 concentrations during peak hour at most sites fall within a range of 40 to 95 micrograms per cubic metre, significantly above the WHO twenty-four-hour guideline. Heavy-duty vehicles and older model cars show disproportionately high emission contributions. Nitrogen dioxide is within WHO guidelines at all sites. Roadside traders experience the longest daily exposure. The study recommends vehicle emission inspection and maintenance programmes and improved intersection traffic signal timing to reduce idling. Keywords: traffic pollution, carbon monoxide, PM2.5, Abuja, vehicular emissions.