Source apportionment of ambient PM2.5 in an industrialized city using dispersion-normalized, multi-time resolution factor analyses

Uwayemi M Sofowote; Dennis Mooibroek; Robert M Healy; Jerzy Debosz; Anthony Munoz; Philip K Hopke

doi:10.1016/j.envpol.2023.121281

Source apportionment of ambient PM_2.5 in an industrialized city using dispersion-normalized, multi-time resolution factor analyses

Environ Pollut. 2023 Apr 15:323:121281. doi: 10.1016/j.envpol.2023.121281. Epub 2023 Feb 15.

Authors

Uwayemi M Sofowote¹, Dennis Mooibroek², Robert M Healy³, Jerzy Debosz³, Anthony Munoz³, Philip K Hopke⁴

Affiliations

¹ Environmental Monitoring and Reporting Branch, Ontario Ministry of the Environment, Conservation and Parks, Toronto, Canada. Electronic address: Uwayemi.Sofowote@ontario.ca.
² Centre for Environmental Monitoring, National Institute for Public Health and the Environment (RIVM), A. van Leeuwenhoeklaan 9, P.O. Box 1, 3720 BA Bilthoven, the Netherlands.
³ Environmental Monitoring and Reporting Branch, Ontario Ministry of the Environment, Conservation and Parks, Toronto, Canada.
⁴ Center for Air Resources Engineering and Science, Clarkson University, Potsdam, NY, USA; Department of Public Health Sciences, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA.

PMID: 36804563
DOI: 10.1016/j.envpol.2023.121281

Abstract

Ambient fine particulate matter (PM_2.5) data were collected in the lower City of Hamilton, Ontario to apportion the sources of this pollutant over an 18-month period. Hamilton has complex topographical features that may result in worsened air pollution within the lower city, thus, dispersion-normalized, multi-time resolution factor analysis (DN-MT-FA) was used to identify and quantify contributions of factors in a manner that reduced the influence of local meteorology. These factors were secondary organic aerosols type 1 (SOA_1), particulate nitrate (pNO3), particulate sulphate (pSO4), primary traffic organic matter (PTOM), Steel/metal processing and vehicular road dust emissions (Steel & Mobile) and, secondary organic aerosols type 2 (SOA_2) with origins ranging from mainly regional to mainly local. Factors that were mainly local (PTOM, Steel & Mobile, SOA_2) contributed up to 17% of the average PM_2.5 mass while mixed local/regional factors (pNO3, pSO4) made up 43% on average, indicating the potential for further reduction of harmful PM concentrations locally. Of particular interest from a health protection perspective, was the composition of PM_2.5 on days when an exceedance of the 24-hr WHO air quality guideline for this pollutant was observed. In general, SOA_1 was found to drive summer exceedances while pNO3 dominated in the winter. During the summer period, SOA_1 was attributable to wildfires in the northern parts of Canada while local traffic sources in winter contributed to the high levels of pNO3. While local, industrial factors only had minor relative mass contributions during exceedances, they are high in highly oxidized organic species (SOA_2) and toxic metals (Steel & Mobile). Thus, they are likely to have more impacts on human health. The methods and results described in this work will be useful in understanding prevalent sources of particulate matter pollution in the ambient air in the presence of complex topography and meteorological effects.

Keywords: DN-MT-FA; Exceedance; Industrial area; ME-2; PM(2.5); Wildfires.

MeSH terms

Cities
Environmental Monitoring* / methods
Factor Analysis, Statistical
Geography
Industrial Development
Models, Theoretical*
Ontario
Particle Size
Particulate Matter* / analysis

Substances

Particulate Matter