Contribution of Traffic Emissions to PM 2.5 Concentrations at Bus Stops in Denver, Colorado

Priyanka deSouza (), Philip Hopke, Christian L’Orange, Peter C. Ibsen, Carl Green, Brady Graeber, Brendan Cicione, Ruth Mekonnen, Saadhana Purushothama, Patrick L. Kinney and John Volckens
Additional contact information
Priyanka deSouza: Department of Urban and Regional Planning, University of Colorado Denver, Denver, CO 80202, USA
Philip Hopke: Institute for a Sustainable Environment, Clarkson University, Potsdam, NY 13699, USA
Christian L’Orange: Department of Mechanical Engineering, Colorado State University, Fort Collins, CO 80523, USA
Peter C. Ibsen: U.S. Geological Survey, Geosciences and Environmental Change Science Center, Lakewood, CO 20192, USA
Carl Green: Regional Transportation District (RTD), Denver, CO 80202, USA
Brady Graeber: Department of Geography and Environmental Sciences, University of Colorado Denver, Denver, CO 80202, USA
Brendan Cicione: Department of Urban and Regional Planning, University of Colorado Denver, Denver, CO 80202, USA
Ruth Mekonnen: Department of Geography and Environmental Sciences, University of Colorado Denver, Denver, CO 80202, USA
Saadhana Purushothama: Department of Geography and Environmental Sciences, University of Colorado Denver, Denver, CO 80202, USA
Patrick L. Kinney: Department of Environmental Health, Boston University School of Public Health, Boston, MA 02118, USA
John Volckens: Department of Public Health Sciences, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, USA

Sustainability, 2025, vol. 17, issue 17, 1-14

Abstract: Individuals are routinely exposed to traffic-related air pollution on their commutes, which has significant health impacts. Mitigating exposure to traffic-related pollution is a key urban sustainability concern. In Denver, Colorado, low-income Americans are more likely to rely on buses and spend time waiting at bus stops. Evaluating the contribution of traffic emissions at bus stops can provide important information on risks experienced by these populations. We measured PM 2.5 constituents at eight bus stops and one background reference site in Denver, in the summer of 2023. Source profiles, including gasoline emissions from traffic, were estimated using Positive Matrix Factorization (PMF) analysis of PM 2.5 constituents collected at a Chemical Speciation Network site in our study region. The contributions of the different sources at each bus stop were estimated by regressing the vector of species concentrations at each site (dependent variable) on the source-profile matrix from the PMF analysis (independent variables). Traffic-related emissions (~2.5–6.6 μg/m 3 ) and secondary organics (~3–5 μg/m 3 ) contributed to PM 2.5 at the bus stops in our dataset. The highest traffic-related emissions-derived PM 2.5 concentrations were observed at bus stops near local sources: a gas station and a car wash. The contribution of traffic-related emissions was lower at the background site (~1 μg/m 3 ).

Keywords: traffic emissions; bus stops; PM 2.5; source apportionment; Positive Matrix Factorization; urban sustainability (search for similar items in EconPapers)
JEL-codes: O13 Q Q0 Q2 Q3 Q5 Q56 (search for similar items in EconPapers)
Date: 2025
References: View references in EconPapers View complete reference list from CitEc
Citations:

Downloads: (external link)
https://www.mdpi.com/2071-1050/17/17/7707/pdf (application/pdf)
https://www.mdpi.com/2071-1050/17/17/7707/ (text/html)

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:gam:jsusta:v:17:y:2025:i:17:p:7707-:d:1733553

Access Statistics for this article

Sustainability is currently edited by Ms. Alexandra Wu

More articles in Sustainability from MDPI
Bibliographic data for series maintained by MDPI Indexing Manager ().