Automotive tire wear as a source for atmospheric OCS and CS 2

The emission of CS 2 , OCS and traces of SO 2 from mixtures of fifteen different ground tire treads has been detected in laboratory experiments using gas chromatography/flame photometric detection (GC/FPD) and gas chromatography/mass spectrometry (GC/MS). Samples of ground tire particles (60–100 mesh) were flushed at different temperatures using either clean nitrogen gas or a mixture of 100 ppb O 3 in N 2 . CS 2 was the dominant sulfur gas detected in all of the experiments. OCS and CS 2 emissions increased strongly with temperature and were independent of the presence of O 3 . In contrast, SO 2 was observed only at high ozone levels. It is roughly estimated that tire wear may produce as much as 0.04 ± 0.004 Tg S (OCS) yr −1 or about 6.7% of the total OCS flux into the atmosphere. Therefore, this as yet undescribed automotive source may make a small but significant contribution to the atmospheric OCS budget.