Measurement of tire tread in urban air by pyrolysis-gas chromatography with flame photometric detection

Abstract

The concentration of tire tread in suspended particulate matter (SPM) was measured by a new method based on benzothiazole generated by pyrolysis of vulcanization accelerator. The variation of production yields of benzothiazole was examined for 24 kinds of tire treads currently used in Japan Pyrolysis was carried out at 670°C using a Curie-point pyrolyzer. The vertical profile and diurnal pattern of tire tread were investigated with 4-h samples continuously collected for 24 h at a heavy traffic density area in Tokyo. The diurnal percentage of tire tread in SPM at the sampling site of 86 m height showed two peaks following the trend of traffic density throughout the day. The concentration of tire tread collected at the 86 m level was about 30% of that at the 0 m level during the daytime. The seasonal variation of concentration of tire tread in SPM was measured at the sampling site located 20 km SW of Tokyo. The weight percentage of tire tread in SPM varied between 1.3 and 3% in winter with NE-NW wind and varied between 0.5 and 1.5% in spring with SE-SW wind.