Pollution characteristics and health risks of PAHs and their nitrated and oxygenated derivatives in the ambient air of a major iron and steel industrial city in South Korea.

The levels, profiles, sources, and health risks of polycyclic aromatic hydrocarbons (PAHs), nitrated PAHs (NPAHs), and oxygenated PAHs (OPAHs) were investigated in Pohang, a major iron and steel industrial city in South Korea. Passive air samplers (PASs) were deployed at 26 sites across port, industrial, and urban areas during winter for a 72-day sampling period. The mean concentrations of 21 PAHs, 17 NPAHs, and 9 OPAHs were 54.6 ng/m3, 530 pg/m3, and 4.8 ng/m3, respectively. The mean PAH concentration at the port area was 3.9 times higher than that in other areas, primarily due to emissions from steel production processes (e.g., sintering and blast furnaces) and ship and truck activities related to cargo handling. Among NPAHs, 1-nitropyrene, a marker of diesel exhaust, was predominant at the port sites, highlighting the contribution of traffic emissions. OPAHs showed a spatial distribution similar to that of PAHs, with 9-fluorenone being the most abundant compound. Correlation analysis, diagnostic ratios, and principal component analysis revealed the influence of primary emission sources, including iron and steel manufacturing, diesel exhaust, and coal combustion, as well as contributions from secondary formation. Cancer risk assessments indicated elevated health risks in the port area, with PAHs being the major contributors. Overall, PAH and N/OPAH levels were largely driven by primary emissions in the port area, while secondary formation played a more significant role in the urban areas. This study is the first in South Korea to report atmospheric levels of both NPAHs and OPAHs using PASs.