SEASONAL-CHANGES IN THE CONCENTRATION OF POLYCYCLIC AROMATIC-HYDROCARBONS IN AZALEA LEAVES AND RELATIONSHIP TO ATMOSPHERIC CONCENTRATION

Seasonal changes in the concentrations of the polycyclic aromatic hydr ocarbons (PAH) perylene, benzo[a]pyrene and pyrene in azalea leaves an d in the atmosphere (measured separately, in the vapor and particulate phases) were followed at two sites with different traffic conditions in Tokyo. The concentrations of the compounds in the leaves (PAH-leV) and in suspended particulate matter (SPM) (PAH-pat) decreased in summe r and increased in winter, whereas the pyrene concentration in the vap or phase decreased from autumn to winter and increased in spring. The concentrations of non-volatile benzo[a]pyrene and perylene in the leav es were approximately proportional to those in SPM. The concentration of volatile pyrene in the leaves was correlated to that in the vapor p hase by an equation based on the Langmuir adsorption hypothesis, log[P AH-vap]/[PAH-lev] = -A/T + B (where A and B are constants and T is tem perature), indicating that most of the pyrene in leaves was taken up b y adsorption from the vapor phase.