Ultrafine Particle Assessment Relating to Near Highway Traffic Combustion and Air Quality Impacts

Focus Area

Air Quality


Air Quality






2-3 years

Research Idea Scope

Ultrafine particles (UFP) can be defined as having at least one dimension that is less than 100 nanometers.  Because of their dimensions, they exhibit unique properties that affect atmospheric transport and are found to be highly concentrated near busy roadways and in frequent stop and go conditions (e.g., toll booths, backups).  Toll booths to date have not been highly characterized for understanding the impacts on air quality related to the constant traffic sources comprising a dynamic mixture of automobile, light duty, and heavy duty diesel truck traffic, which all produce under stop and go conditions high levels of ultrafine particles.  In other cases, it is expected the UFP will be elevated where entrance and exits are in the same direction that can result in severe traffic backups from traffic making left turns into the entrance lane or traffic waiting for lights to turn upon exit from the highway that can result in extended idling and stop and go conditions and adverse impacts on near roadway air quality.  Areas such as these can be compared to other locations where traffic is much more systematically separated by ramps and exits that cause lanes to separate away from one another that will likely result in reduced waiting time, better flow despite similar traffic volume and less of an impact on near roadway air quality.  It is, therefore, becoming increasingly important to gain a better understanding of near roadway impacts of UFP across micro- and macro-scale environments resulting from impacts of heavy traffic volumes utilizing state and/or federal highways and exit systems.  In addition, the contribution of such stop-and-go traffic sources on UFP particle populations on the neighborhoods in their vicinity needs to be modeled to permit the extrapolation to other conditions (greater numbers of vehicles, different dispersion conditions, etc).  These models need to be appropriate for near road locations.  Such models must accurately account for the complex interaction of the particle dispersion with the turbulent flow field as affected by the local traffic and terrain.  Such models would provide good area source estimates that could be used in larger scale models for air quality or exposure assessments.

Urgency and Payoff

This research would address a major data gap for understanding state and federal near roadway air quality and potential human health impacts related to heavily traveled state and federal highways for a variety of combustion sources both for workers involved in daily operations of highways (e.g., toll booths operators) and to assess the impacts of air quality for different on and off road ramps that may result in improvement of air quality resulting from better design to maximize flow under heavy traffic volumes and thereby lessoning the overall impact on air quality to surrounding areas.

Suggested By

Timothy R. McAuley, President and Founder, CHANGE, Consulting for Health, Air, Nature, & a Greener Environment

[email protected]