Levels and health risk assessments of particulate matter and inorganic gaseous pollutants in urban and industrial areas of Hawassa city, Ethiopia

Air pollution is a global public health concern due to its harmful health effects. However, there is scarce data on concentrations and sources of inorganic gaseous pollutants (NO2, CO, and SO2) and particulate matter (PM2.5 and PM10) in Ethiopia, particularly Hawassa City. Thus, the goal of this research is to determine the indoor and outdoor concentrations of PM2.5, PM10, NO2, CO, and SO2 in urban and industrial areas of Hawassa City, Ethiopia, and to evaluate potential health concerns. A portable gas monitor device (HoldPeak Laser PM meter, HP 5800D) was used to measure the levels of PM10 and PM2.5. The Aeroqual Series 500 Portable Air Quality Monitor (Aeroqual Ltd., New Zealand) was used to measure the concentrations of NO2, CO, and SO2. The results of this study showed that the average concentrations of PM2.5, PM10, and NO2 ranged from 8.8 to 310.7, 20.1-515.8, and 40.0-123.7 mu g/m3, respectively, during the dry season. In the wet season, the ranges for PM2.5, PM10, NO2, and CO levels were 17.2-117.4, 24.3-167.2, 31.8-111.3, and 77-33312 mu g/m3, respectively. The wide range of variations in the concentrations of PM2.5, PM10, NO2 and CO variations may be related to spatial and temporal factors such as sampling locations and seasonal changes. In both the wet and dry seasons, the hazard quotient (HQ) for PM2.5 and PM10 was greater than one, suggesting a non-carcinogenic effect. The PM2.5 excess lifetime cancer risk (ELCR) ranged from 0.1 to 0.7, which is greater than the recommended values by the WHO (ranging from 1 x 10-5 to 1 x 10-6) and the USEPA (less than 1 x 10-6). The HQ and ELCR values imply a considerable health risk for the general population.