Polycyclic aromatic compounds in urban air and associated inhalation cancer risks: A case study targeting distinct source sectors

Narumol Jariyasopit; Phoebe Tung; Ky Su; Sabina Halappanavar; Greg J Evans; Yushan Su; Sakda Khoomrung; Tom Harner

doi:10.1016/j.envpol.2019.06.015

Polycyclic aromatic compounds in urban air and associated inhalation cancer risks: A case study targeting distinct source sectors

Environ Pollut. 2019 Sep;252(Pt B):1882-1891. doi: 10.1016/j.envpol.2019.06.015. Epub 2019 Jun 6.

Authors

Narumol Jariyasopit¹, Phoebe Tung², Ky Su², Sabina Halappanavar³, Greg J Evans⁴, Yushan Su⁵, Sakda Khoomrung⁶, Tom Harner⁷

Affiliations

¹ Air Quality Processes Research Section, Environment and Climate Change Canada, Toronto, Ontario, M3H 5T4, Canada; Siriraj Metabolomics and Phenomics Center, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, 10700, Thailand.
² Air Quality Processes Research Section, Environment and Climate Change Canada, Toronto, Ontario, M3H 5T4, Canada.
³ Mechanistic Studies Division, ERHSD, HECSB, Health Canada, Ottawa, Canada.
⁴ Department of Chemical Engineering and Applied Chemistry, University of Toronto, Ontario, M5S 3E5, Canada.
⁵ Ontario Ministry of the Environment, Conservation and Parks, Toronto, Ontario, Canada.
⁶ Siriraj Metabolomics and Phenomics Center, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, 10700, Thailand; Department of Biochemistry, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, 10700, Thailand; Center for Innovation in Chemistry (PERCH-CIC), Faculty of Science, Mahidol University, Rama 6 Road, Bangkok, 10400, Thailand.
⁷ Air Quality Processes Research Section, Environment and Climate Change Canada, Toronto, Ontario, M3H 5T4, Canada. Electronic address: tom.harner@canada.ca.

PMID: 31227350
DOI: 10.1016/j.envpol.2019.06.015

Abstract

Passive air sampling was conducted in Toronto and the Greater Toronto Area from 2016 to 2017 for 6 periods, in order to investigate ambient levels of polycyclic aromatic compounds (PACs) associated with different source types. The selected sampling sites (n = 8) cover geographical areas with varying source emissions including background, traffic, urban, industrial and residential sites. Passive air samples were analyzed for PACs which include PAHs, alkylated PAHs (alk-PAHs), dibenzothiophene and alkylated dibenzothiophenes (DBTs) and results for PAHs were used to calculate inhalation cancer risks using different approaches. The samples were also characterized for PAH derivatives including nitrated PAHs (NPAHs) and oxygenated PAHs (OPAHs). Concentrations of Σalk-PAHs and DBTs, which are known to be enriched in fossil fuels, as well as ΣNPAHs, were highest at a traffic site (MECP) located adjacent to the 18-lane Highway 401 that runs across Toronto. Except for an industrial site (HH/BU), PAC compositions were similar across the sampling sites with Σalk-PAHs being the most abundant class of PACs suggesting traffic emission was a major contributor to PACs in the atmosphere of Toronto. The industrial site exhibited a distinct chemical composition with ΣPAHs dominating over Σalk-PAHs and with elevated levels of fluoranthene, 9-nitroanthracene, and 9,10-anthraquinone, which likely reflects emissions from nearby industrial sources. MECP and HH/BU exhibited higher lifetime excess inhalation cancer risks indicating an association with traffic and industrial sources. The importance of the traffic sector as a source of PACs to ambient air is further supported by strong correlations of the ΣPAHs, Σalk-PAHs, DBTs, and ΣOPAHs with NO_x. This study highlights the importance of traffic as an emission source of PACs to urban air and the relevance of PAC classes other than just unsubstituted PAHs that are important but currently not included in air quality guidelines or for assessing inhalation cancer risks.

Keywords: Alkylated PAHs; Inhalation cancer risk; NPAHs; OPAHs; PAHs; Passive air sampling; Urban air pollution.

MeSH terms

Air Pollutants / analysis*
Air Pollution / analysis*
Anthracenes / analysis
Anthraquinones / analysis
Atmosphere / chemistry
Canada / epidemiology
Environmental Monitoring / methods*
Fluorenes / analysis
Humans
Neoplasms / chemically induced*
Neoplasms / epidemiology*
Nitrates / analysis
Nitrogen Oxides / analysis
Polycyclic Aromatic Hydrocarbons / analysis*
Thiophenes / analysis
Vehicle Emissions / analysis

Substances

Air Pollutants
Anthracenes
Anthraquinones
Fluorenes
Nitrates
Nitrogen Oxides
Polycyclic Aromatic Hydrocarbons
Thiophenes
Vehicle Emissions
9,10-anthraquinone
fluoranthene
9-nitroanthracene
dibenzothiophene