Interaction between polycyclic aromatic hydrocarbons (PAHs) and mineral grains with clarification of PAHs carrier in the atmosphere

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Long range transport of Polycyclic aromatic hydrocarbons (PAHs) with Asian dust was investigated by collecting Aerosol particles through a year from April 2003 at Kanazawa, Japan. PAHs content in Asian dust particles were highly variable in different Asian dust events. Developed kinetic model showed that sorption rate of less volatile PAHs than BaP on Asian dust particles are too low to be accumulated. The origin of those PAHs in Asian dust particles would be originally PAH-polluted soil particles around industrialized area (e.g. loess regions around industrialized area). Back trajectory analyses also showed Asian dust with high less volatile PAHs content would have derived from loess area while Asian dust with undetectable amount of PAHs would have had source region in Mongolia and northern China. The stability of Pyr (a model PAHs) on different component of Asian dust particles was investigated under controlled temperature and relative humidity (RH) condition with/without light irradiation. Sianol and aluminol catalyze PAHs decomposition in the dark with enhanced catalytic effect by rinse in RH and light irradiation. Clay minerals protect Pyr against rise in RH and light irradiation to last several days. Most realistic carrier of PAHs is clay minerals. Geologic materials contribute atmospheric circulation of PAHs over long distance than previously thought.