| Study | Location | Transport | In vehicle benzene mean concentration (µg/m3) |
| This study | Central Valley, Costa Rica | Personal car | 22.3 |
| Non-A/C bus | 38.3 | ||
| Urban train | 33.0 | ||
| Gomez-Perales et al. (2001) | Mexico City | Minibus | 22.3 |
| Bus | 19.1 | ||
| Metro | 12.8 | ||
| Chan et al. (2003) | Guangzhou, China | Subway | 7.6 |
| Taxi | 33.6 | ||
| Non-A/C bus | 11.3 | ||
| A/C bus | 13.5 | ||
| Chertok et al. (2004) | Sydney, Australia | Car | 39.2 |
| Bus | 22.1 | ||
| Train | 12.0 | ||
| O’Donoghue et al. (2007) | Dublin, Ireland | Bus | 7.0 |
| Ongwandee and Chavalparit, (2010) | Bangkok, Thailand | A/C bus | 39.1 |
| Non-A/C bus | 57.1 | ||
| Sky train | 13.2 |