CHARACTERIZATION OF CARBONACEOUS AEROSOLS IN THE NAGOYA URBAN AREA .2. BEHAVIOR AND ORIGIN OF PARTICULATE N-ALKANES

Measurements of concentrations, size distributions, and vapor-to-particle partitioning for n-alkanes in ambient aerosols were made in the Nagoya urban area. The average concentration of total particulate n-alkanes in the winter was roughly 6 times higher than that in the summer. The distribution profiles of particulate n-alkanes in the summer showed a saw-tooth pattern (odd > even) in the range C27-C35. On the other hand, in the winter a nearly Gaussian distribution with a maximum around C22 overlapped with the saw-tooth pattern. It was found that a major cause of the seasonal changes in the lower n-alkanes of the distribution profiles is not a change in fossil fuel emissions, but rather vapor-to-particle partitioning. Particulate n-alkanes were predominantly associated with fine particles, and the saw-tooth pattern occurred clearly in the fine particle range rather than in the coarse one. These results suggest that particulate n-alkanesin Nagoya mainly originate from anthropogenic combustion sources of fossil fuels and contemporary biological materials; however, the summer combustion of fossil fuels hardly contributes as a source of particulate n-alkanes due to changes in the partitioning behavior.