Maritime ports are major sources of urban air pollution, but surface monitoring often fails to capture pollution at higher levels from ship exhaust stacks and coastal atmospheric processes, a gap especially important for Global South ports. Here we conducted a height-resolved assessment at the Port of Paranaguá in Brazil during the southern hemisphere spring. Using multi-height measurements combined with meteorological analysis and a space-and-time-stratified case-crossover approach, we identified strong vertical differences in pollutant concentrations. Sulfur dioxide was consistently elevated at heights corresponding to ship exhaust, indicating interception of ship plumes. Nitrogen dioxide showed a weaker but consistent increase at mid-levels, influenced by port activity and atmospheric mixing. Fine particulate matter showed modest enhancement aloft, while the strongest operation-related episodes occurred near the surface. Pollution risk increased substantially during port operations, rising by up to 74% during cargo handling. These findings show that surface-only monitoring fails to capture the full extent of exposure-relevant pollution in port environments. Air pollution in a major Brazilian port is strongly elevated above the surface and intensifies during port operations, which surface monitoring misses, based on multi-height air measurements combined with meteorology and a case crossover analysis during spring.
Santos-Silva et al. (Sat,) studied this question.