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Spatial Distribution of Ultrafine Aerosol Population from Local Sources
Start Date 08/01/08
End Date 07/31/09
Primary Partner: Clarkson University
Primary Contact: Dhaniyala, Suresh - Professor
Project Type: CARTI III
Technical Description:
Ultrafine particles are speculated to have a particularly adverse effect on human health. In urban environments, a major source of these particles is traffic exhaust from highways. There have been several studies on the horizontal decay of highway-generated particle number concentration as a function of distance from the road. The particle dispersion characteristics in the vertical direction, however, are not completely known and this mechanism may critically control particle concentration field in urban areas. Field measurements will be conducted near Syracuse, NY with a variety of particle instruments to determine their dispersion at high temporal and spatial resolution. The data will be used to develop a new near road pollutant dispersion model that will eventually be integrated with urban-scale pollutant transport models.
Expected Outcomes:
The high spatial- and temporal- resolution particle measurements near roadways will provide critical data to develop/test next generation models for accurate prediction of urban-scale aerosol dispersion.
Accomplishments:
Field measurements were conducted near the I-90 freeway in Liverpool, NY (near Syracuse, NY) during August and September, 2009 for measurements of particle concentration profiles in both the vertical and horizontal directions. A 10m-high tower was used to sample particles from the ground to the top of the tower at nine different heights.
In addition, gas-phase pollutants - carbon monoxide and carbon dioxide - were also measured. Real-time measurements of particulate polycyclic aromatic hydrocarbons (PAHs) were also obtained as a function of sampling height. Horizontally, the tower was sequentially located at 15m, 50m, and 100m from the edge of the highway.
The high-resolution vertical measurements provided some of the first data of particle plumes rising from freeways. Analysis of the entire data set is currently underway to determine the particle dispersion characteristics as a function of wind and traffic conditions, particle size, sampling location, etc. The data from these measurements are being used to evaluate a new near roadway dispersion model.
Benefits:
Understanding the vertical and horizontal dispersion of particles originating from traffic exhaust, will enhance our knowledge of the contribution of these sources to local air pollution in urban areas. The development of a near roadway dispersion model and its integration with regional air quality models will help us better estimate the role of traffic sources on human health.
Publications:
Meilu He and Suresh Dhaniyala. “Development of a Dispersion Model for Traffic Produced Turbulence” Sent for publication to Atmospheric Environment, Jan 2010.
For more information: http://www.clarkson.edu/mae/faculty_pages/dhaniyala.html
Vertical particle concentration fields showing rising plumes near the roadways
Image Credit: Suresh Dhaniyala, Clarkson University
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