Asmare Asrat Yirdaw ^1* Amanuel Ejeso ² Samrawit Mokie Belayneh ¹ Lamrot Yohannes ³ Anmut Endalkachew Bezie ⁴ Embialle Mengistie Beyene ²

• ¹ Department of Environmental Health, College of Medicine and Health Science, Arba MInch University, Arba Minch, Ethiopia
• ² Department of Environmental Health, College of Medicine and Health Science, Hawassa University, Hawassa, Ethiopia, Hawassa, Ethiopia
• ³ Department of Environmental and Occupational Health and Safety, Institute of Public Health, College of Medicine and Health Sciences, University of Gondar, Gondar, Amhara Region, Ethiopia
• ⁴ Department of Occupational Health and Safety, College of Medicine and Health Sciences, Wollo University., Dessie, Amhara, Ethiopia

The traffic air pollution caused by transportation is a growing global problem that contributes to millions of deaths each year. Despite its importance, information on pollutant concentration is limited in many developing cities, especially in Ethiopia. This study aimed to determine the concentration levels and spatial and temporal variations of traffic air pollutants in Hawassa and to investigate the influence of metrological parameters on the concentration of traffic air pollutants. A real-time monitoring system of Aero-Qual Series 300/500 was used to monitor pollutants, and 24 monitoring sites were included on both heavy and low-traffic volume roads.The study monitored morning and afternoon times over 24 days to comprehensively characterize the temporal variations. The results showed that the mean PM 2.5 concentration on heavy-and low-traffic volume roads was 161.6 ± 26.1 µg/m 3 and 95 ± 14.2 µg/m 3 , respectively, whereas the PM 10 concentration was 178.7± 20.3 µg/m 3 and 102.3 ± 17.6 µg/m 3 , respectively. Similarly, the mean NO 2 concentrations on roads with heavy and low traffic volumes were 86.4 ± 14.4 µg/m 3 and 61.7 ± 14.2 µg/m 3, respectively. Significantly higher, concentrations were recorded on traffic light roads, followed by main asphalt roads, for both types of traffic air pollutants. The ratio of PM 2.5 /PM 10 was higher (0.924), in which the pollution sources attributed to anthropogenic sources. Kendall's tau-b correlation analysis suggested that Meteorological parameters (temperature and relative humidity) were positively correlated with traffic air pollutants. Likewise, stepwise multiple linear logistic regression analysis confirms that the concentrations of traffic air pollutants had a positive relationship with metrological parameters. Implications: The findings of this study therefore showed the need for regular air quality monitoring of the urban areas to copping out the adverse public health impacts. And, it highlighted an urgent need for long-term monitoring of traffic air pollution and the development of emission control programs that can be readily implemented to decrease the emissions from anthropogenic sources. Also, it brings a sense of collaboration among stakeholders to tackle the effects of air pollution by providing an inclusive and sustainable development agenda for Hawassa.