Comparison of polymeric components and tire wear particle contents in particulate matter collected at bus stop and college campus

Particulate matter (PM(2.5)) samples were collected at two different places of a college campus (CC) and a bus stop (BS) nearby the college campus. The traffic volume of college campus was very low due to untact classes. Polymeric components and tire wear particle (TWP) contents in the PM(2.5) samples were analyzed using pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). Various polymeric components such as natural rubber (NR), bitumen, saturated hydrocarbons, poly(ethylene terephthalate) (PET), and plant-related particles (PRPs) were observed. NR and bitumen are key components of TWP of bus tire tread and asphalt pavement wear particle (APWP), respectively. The TWP contents in the PM(2.5) samples collected at the bus stop were larger than those collected at the college campus. For the same sampling site, the TWP content in the PM(2.5) sample collected for higher fine dust concentration in the air was greater than that for lower one. The TWP(2.5) concentration in the air for the BS sampling was higher than those for the CC sampling, even when the PM(2.5) concentration in the air for the former was lower than those for the latter. It can be concluded that the TWPs and APWPs in the PM(2.5) samples collected at the college campus should be transferred mostly from the outside road.