Influence of local human population on atmospheric polycyclic aromatic hydrocarbon concentrations.

Literature values of atmospheric polycyclic aromatic hydrocarbon (PAH) concentrations from sampling sites around the world were found, and using a high-resolution human population grid, the population within a 25-km radius of each sampling site was calculated. A regression of concentration vs population revealed much about PAH concentration differences among regions as well as site locations within a continent. The best fit for the regression was for sampling locations in North America. A small amount of scatter was present for the regression of all developed countries indicating slight differences in emission regulations or energy usage. The regression from this plot was used as a benchmark for the expected relationship between PAHs and human population. Sites located within 25 km of a coasttended to have concentrations lower than expected, due to dilution with clean ocean air, while sites near industrial outputs or other point sources had higher than expected concentrations. Sites from developing countries typically had PAH concentrations that were far higher than those of the rest of the world.