Quantifying factors affecting contributions of roadway exhaust and non-exhaust emissions to ambient PM102.5 and PM2.50.2 particles

Vasileios N. Matthaios*, Joy Lawrence, Marco A.G. Martins, Stephen T. Ferguson, Jack M. Wolfson, Roy M. Harrison, Petros Koutrakis

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

30 Downloads (Pure)

Abstract

Traffic-related particulate matter (PM) plays an important role in urban air pollution. However, sources of urban pollution are difficult to distinguish. This study utilises a mobile particle concentrator platform and statistical tools to investigate factors affecting roadway ambient coarse particle (PM102.5) and fine particle (PM2.50.2) concentrations in greater Boston, USA. Positive matrix factorization (PMF) identified six PM102.5 sources (exhaust, road salt, brake wear, regional pollution, road dust resuspension and tyre-road abrasion) and seven fine particle sources. The seven PM2.50.2 sources include the six PM102.5 sources and a source rich in Cr and Ni. Non- exhaust traffic-related sources together accounted for 65.6% and 29.1% of the PM102.5 and PM2.50.2 mass, respectively. While the respective contributions of exhaust sources were 10.4% and 20.7%. The biggest non-exhaust contributor in the PM102.5 was road dust resuspension, accounting for 29.6%, while for the PM2.50.2, the biggest non-exhaust source was road-tyre abrasion, accounting for 12.3%. We used stepwise general additive models (sGAMs) and found statistically significant (p < 0.05) effects of temperature, number of vehicles and rush hour periods on exhaust, brake wear, road dust resuspension and road-tyre abrasion with relative importance between 19.1 and 62.2%, 12.5–42.1% and 4.4–42.2% of the sGAM model's explained variability. Speed limit and road type were also important factors for exhaust, road-tyre and brake wear sources. Meteorological variables of wind speed and relative humidity were significantly associated with both coarse and fine road dust resuspension and had a combined relative importance of 38% and 48%. The quantifying results of the factors that influence traffic-related sources can offer key insights to policies aiming to improve near-road air quality.

Original languageEnglish
Article number155368
Number of pages10
JournalScience of the Total Environment
Volume835
Early online date21 Apr 2022
DOIs
Publication statusPublished - 20 Aug 2022

Bibliographical note

Funding Information:
Research described in this article was conducted under contract to the Health Effects Institute (HEI), an organization jointly funded by the United States Environmental Protection Agency (U.S. EPA) (Assistance Award No. CR-83467701 ) and certain motor vehicle and engine manufacturers. The contents of this article do not necessarily reflect the views of HEI, or its sponsors, nor do they necessarily reflect the views and policies of the EPA or motor vehicle and engine manufacturers. This publication was made possible by U.S. EPA grant RD-83587201 . Its contents are solely the responsibility of the grantee and do not necessarily represent the official views of the U.S. EPA. Further, U.S. EPA does not endorse the purchase of any commercial products or services mentioned in the publication. VNM was further supported by the European Union's Horizon 2020 Research and Innovation Programme under the Marie Sklodowska-Curie Grant Agreement No 895851 .

Publisher Copyright:
© 2022 Elsevier B.V.

Keywords

  • Air quality
  • Non-exhaust
  • Particulate matter
  • Road traffic
  • Source apportionment

ASJC Scopus subject areas

  • Environmental Engineering
  • Environmental Chemistry
  • Waste Management and Disposal
  • Pollution

Fingerprint

Dive into the research topics of 'Quantifying factors affecting contributions of roadway exhaust and non-exhaust emissions to ambient PM102.5 and PM2.50.2 particles'. Together they form a unique fingerprint.

Cite this