PM2.5 and PM10-2.5 chemical composition and source apportionment near a Hong Kong roadway

- PM2.5 and PM10 samples were collected simultaneously at a roadside site in Hong Kong.
- PM10-2.5 showed different chemical composition and potential sources from PM2.5.
- OC, EC, SO42−, NH4+, and K+ were more abundant in the fine fraction.
- Cl−, Al, Si, Ca, Ti, and Fe were enriched in the coarse fraction.
- Potential source apportionments were estimated for PM10-2.5.