A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
Seasonal variability of ultra-fine metals downwind of a heavily traveled secondary road
Abstract Since 2002, we have been studying the impact of a heavily traveled secondary road on an adjacent downwind school located at a stop light controlled intersection. The prior studies were all performed in winter conditions with typically strong inversions, but established significant PM2.5 impacts on the school roughly in accord with theoretical models and the relevant literature. In this project, we have enhanced this effort by extending the study from winter to summer, and adding compositionally-resolved ultra-fine aerosol measurements. Ultra-fine aerosols, including metals derived from both brake wear and zinc in lubricating oil, were present at high concentrations in winter downwind of the roadway but absent at a residential site 500 m upwind. Their concentrations faded to minor levels in spring and early summer, while coarse roadway resuspended dust increased in that period. A comparison of ultra-fine measurements in downtown Sacramento and other California Central Valley sites indicates that these traffic derived aerosols are widely present in urban areas impacted by heavy traffic, freeways and secondary streets, especially where heavy braking is occurring. The potential for health impacts of ultra-fine metals associated with cars braking and accelerating in inversion conditions is a serious health concern based on recent epidemiological studies.
Highlights Ultra-fine transition metals were measured downwind of a road. Concentrations were <10% at a suburban site 500 m upwind. The sources of the metals were brake wear and zinc in lubricating oil. Similar ultra-fine metals associate with ischemic heart disease in California. Concentrations decreased sharply (∼×0.1) as one went from winter into spring.
Seasonal variability of ultra-fine metals downwind of a heavily traveled secondary road
Abstract Since 2002, we have been studying the impact of a heavily traveled secondary road on an adjacent downwind school located at a stop light controlled intersection. The prior studies were all performed in winter conditions with typically strong inversions, but established significant PM2.5 impacts on the school roughly in accord with theoretical models and the relevant literature. In this project, we have enhanced this effort by extending the study from winter to summer, and adding compositionally-resolved ultra-fine aerosol measurements. Ultra-fine aerosols, including metals derived from both brake wear and zinc in lubricating oil, were present at high concentrations in winter downwind of the roadway but absent at a residential site 500 m upwind. Their concentrations faded to minor levels in spring and early summer, while coarse roadway resuspended dust increased in that period. A comparison of ultra-fine measurements in downtown Sacramento and other California Central Valley sites indicates that these traffic derived aerosols are widely present in urban areas impacted by heavy traffic, freeways and secondary streets, especially where heavy braking is occurring. The potential for health impacts of ultra-fine metals associated with cars braking and accelerating in inversion conditions is a serious health concern based on recent epidemiological studies.
Highlights Ultra-fine transition metals were measured downwind of a road. Concentrations were <10% at a suburban site 500 m upwind. The sources of the metals were brake wear and zinc in lubricating oil. Similar ultra-fine metals associate with ischemic heart disease in California. Concentrations decreased sharply (∼×0.1) as one went from winter into spring.
Seasonal variability of ultra-fine metals downwind of a heavily traveled secondary road
Cahill, Thomas A. (author) / Barnes, David E. (author) / Spada, Nicholas J. (author)
Atmospheric Environment ; 94 ; 173-179
2014-05-12
7 pages
Article (Journal)
Electronic Resource
English
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