Particle formation and growth at five rural and urban sites
Date
2010
Authors
Jeong, C-H
Evans, G. J.
McGuire, M. L.
Chang, R. Y-W
Abbatt, J. P. D.
Zeromskiene, K.
Mozurkewich, M.
Li, S. -M
Leaitch, Andw R.
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
Ultrafine particle (UFP) number and size distributions were simultaneously measured at
five urban and rural sites during the summer of 2007 in Ontario, Canada as part of the
Border Air Quality and Meteorology Study (BAQS-Met 2007). Particle formation and growth
events at these five sites were classified based on their strength and persistence as
well as the variation in geometric mean diameter. Regional nucleation and growth events
and local short-lived strong nucleation events were frequently observed at the
near-border rural sites, upwind of industrial sources. Surprisingly, the particle number
concentrations at one of these sites were higher than the concentrations at a downtown
site in a major city, despite its high traffic density. Regional nucleation and growth
events were favored during intense solar irradiance and in less polluted cooler drier
air. The most distinctive regional particle nucleation and growth event during the
campaign was observed simultaneously at all five sites, which were up to 350 km apart.
Although the ultrafine particle concentrations and size distributions generally were
spatially heterogeneous across the region, a more uniform spatial distribution of UFP
across the five areas was observed during this regional nucleation event. Thus,
nucleation events can cover large regions, contributing to the burden of UFP in cities
and potentially to the associated health impacts on urban populations. Local short-lived
nucleation events at the three near-border sites during this summer three-week campaign
were associated with high SO2, which likely originated from US and Canadian industrial
sources. Hence, particle formation in southwestern Ontario appears to often be related
to anthropogenic gaseous emissions but biogenic emissions at times also contribute.
Longer-term studies are needed to help resolve the relative contributions of
anthropogenic and biogenic emissions to nucleation and growth in this region.
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Citation
Jeong, C-H, G. J. Evans, M. L. McGuire, R. Y-W Chang, et al. 2010. "Particle formation and growth at five rural and urban sites." Atmospheric Chemistry and Physics 10(16): 7979-7995.