Comparative assessment of black carbon levels in public transit systems across three cities

Authors

• Alejandro Perez Villasenor
• Xudong Wang
• Jill Baumgartner
• Luis Miranda-Moreno

Document Type

Journal Article

Publication Date

2025

Subject Area

mode - bus, mode - bus rapid transit, mode - subway/metro, place - north america, place - urban, planning - environmental impact, technology - emissions

Keywords

Black carbon, Public transit, Indoor air quality

Abstract

This research investigates users’ exposure to black carbon (BC) in subways, buses, and BRTs. The study was conducted in Mexico City and Puebla (Mexico) and Montreal (Canada) to identify city-specific variations across modes and factors associated with levels of BC. Over 1500 min were collected, and regression model analyses were used to identify the impacts of mode and other factors. Among all measured transit modes, subway systems exhibited the highest BC concentrations (median: 10.83 μg/m³ ; MAD: ±6.97 μg/m³). In contrast, BRT systems showed the lowest exposure levels (3.7228 ± 2.27 μg/m³), with buses demonstrating comparable concentrations (4.00 ± 2.22 μg/m³). Notably, high concentrations in subways are primarily observed in segments where the subway operates in underground tunnels. Both surface transit modes measured slightly above ambient outdoor levels (2.82 ±1.66 μg/m³), suggesting minimal additional exposure during above-ground commute.

Rights

Permission to publish the abstract has been given by Elsevier, copyright remains with them.

Comments

Transportation Research Part D Home Page:

http://www.sciencedirect.com/science/journal/13619209

Recommended Citation

Villasenor, A. P., Wang, X., Baumgartner, J., & Miranda-Moreno, L. (2025). Comparative assessment of black carbon levels in public transit systems across three cities. Transportation Research Part D: Transport and Environment, 146, 104904.