Metal Composition of PM2.5 in the 4 Seasons of Gwangju in South Korea and Implications for Risk to Human Health

Abstract

PM2.5, a sophisticated mixture of multiple chemical and biological species has recently emerged as the most important air pollutant in South Korea. Among these components, metals, five of which were assessed for this study, pose high toxicity risk because of persistence in the environment and biological accumulation within the breathing organism. In order to determine the metal concentrations of Pb, As, Cd, Mn, and Zn, samples of ambient PM2.5 were collected at two sites, GIST and RIPHE in Gwangju, one of the 6 largest cities in South Korea. The samples were taken from all four seasons at RIPHE and from spring, summer, and winter at GIST to investigate the seasonal variability of metal concentrations. On average, the lowest concentrations for all metals except Mn were observed during summer at both sites. The highest average concentrations of the metals were found during spring (Mn and Cd at both sites, Zn at GIST), fall (Pb and As at RIPHE), and winter (Pb and As at GIST, Zn at RIPHE). Significant differences in seasonal concentrations were noted for As and Mn at GIST and for Pb, Cd, and Mn at RIPHE. The Asian dust event was also observed during the sampling period and influenced the peak in concentrations of Mn and As. To evaluate the risk to health from exposure to these metals, the concentrations were compared against the international guidelines and standards. Health risk calculations were also done for cancer and non-cancer risks of Pb, As, and Cd exposure. The assessment showed that none of the metals posed risk to human health.