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Air and Climate Change Research

Near-Roadway Research

Brick Barrier Walls along highway
Understanding the Role of Traffic Emissions on Near-Road Air Quality and Population Exposures

With over 35 million people in the United States living within 300 feet of a major road, there is growing concern about the health impacts from the air pollutants associated with the cars, trucks and other vehicles on them.

Studies have shown that people who live, work, or attend school near major roads have an increased incidence and severity of health problems that may be related to air pollution from roadway traffic. Health effects include reduced lung function and impaired development in children, asthma, cardiovascular disease, low birth weight, and pre-term newborns, and premature death.

Research is needed to better understand what type of pollutants are common near roadways, how people are exposed to them, the extent of exposure, and the type and severity of health effects.

The Near Roadway research focus is to learn more about emissions and how they disperse near a roadway (e.g., emission gradient). Our research will also address:

  • How barriers (e.g., walls and vegetation) can influence or even reduce exposure to near-road pollutants?
  • How these pollutants can be reduced or eliminated in school buildings by using technologies that modify the ventilation system or reduce infiltration?

U.S. EPA. (2010). "The Role of Vegetation in Mitigating Air Quality Impacts from Traffic Emissions." Workshop, RTP, NC, April 27-28.

Scientific Objective

EPA's Clean Air Research Program has launched a multidisciplinary series of near-roadway studies to learn more about air pollution near roads. The research objectives are to:

  • Identify and define mobile source emissions through direct measurements of vehicles and monitoring near roads with varied traffic levels and vehicle classifications
  • Assess factors affecting the variability of near-road air pollutants, such as traffic activity and roadway-design features
  • Improve modeling tools for near-road air quality and human exposure assessments
  • Assess the health effects from near-roadway exposures

Key scientific questions include:

  • How do traffic and roadway emissions affect exposures and adverse health effects for populations living, working, or going to school near roads?
  • What decision tools are available, or can be produced, to identify the relationship from traffic emissions to population exposures and to adverse health effects for use in regulatory decision-making and transportation planning?
  • Do public facilities located near major roadways present an exposure and health risk to their occupants?

Application and Impact

The near-roadway research will provide important scientific data and tools for federal, state and local governments and organizations to make decisions about future road projects and to address health concerns related to roadways. The research will be used in the development of federal regulatory and voluntary programs to reduce air pollution along highways. State highway and environmental agencies can use the science to assess the local health impacts of transportation decisions.

The information also can assist local school districts with decisions on whether to locate new schools near large roadways, and how to mitigate impacts from local roads on existing schools.

With data collected from the roadway studies, numerous scientific papers and products will be prepared that will improve knowledge about the impacts of traffic emissions on air quality near roads and the possible links to adverse health effects.


Air and Climate Change Research | Water Research | Ecosystems Restoration Research | Land Research | Technology: Sustainable Technologies Research, Environmental Technology Verification Program (ETV), and Technology Assessments

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