Concentration and variation of traffic-related air pollution as measured by carbon monoxide in Hawassa City, Ethiopia

Abstract

Air pollution is a pressing problem and causes millions of deaths each year related to its effects on respiratory health worldwide. Despite its significant impact, information on air pollution in many cities, including Hawassa city, remains limited. The aim of this study was to determine the concentrations and variations of traffic-related air pollution, as measured by carbon monoxide, and its relationship with temperature, relative humidity, traffic flow, and road routing in Hawassa City. We monitored carbon monoxide (CO) concentrations in Hawassa city, Ethiopia, for 24 days using real-time monitors with carbon monoxide sensor head. A total of 24 different roads (12 high-traffic congested roads and 12 low-traffic congested roads) were included as monitoring sites. We conducted 1 hour monitoring at each monitoring site in the morning and afternoon to characterize the temporal variations. Accordingly, the average carbon monoxide concentrations varied temporally at different times. In addition, the average carbon monoxide concentrations on paved main roads, traffic light roads and low-traffic flow roads were 4.87 ± 0.6 ppm, 5.38 ± 0.8 ppm and 1.62 ± 0.53 ppm, respectively. The study also identified factors that correlated positively with carbon monoxide concentration, including temperature, relative humidity, traffic flow and road routing. The study concludes that long-term monitoring of carbon monoxide concentrations is necessary to fully characterize the health effects. The study also provides valuable insights for urban planners when implementing measures to mitigate the negative effects.