TUSCALOOSA, Ala. – Even though emissions of particulate matter (PM) have decreased significantly since the passage of the Clean Air Act in 1970, there are still millions of people living and working in areas with PM concentrations well above the national standard. Researchers at The University of Alabama and the University of Alabama at Birmingham are leading efforts to understand the contribution of roadways in Birmingham to the amount of fine particles in the air.

Dr. Derek Williamson, assistant professor of civil and environmental engineering at UA, and Dr. Steven Jones, assistant professor of civil and environmental engineering at UAB, are working with the Jefferson County Department of Public Health to measure fine particulate emissions from roadways in Birmingham. The impact of traffic flow, weather, and the percentage of tractor trailer trucks are being examined by measuring emissions under varying conditions. The goal of this research is to produce correlations specific to Birmingham to estimate the contribution of roadways to fine particle concentrations in the lower atmosphere from already available traffic and weather data.

“Transportation planners will be required to develop inventories of these emissions, however, the data is not available in many areas in Alabama and throughout the country,” explained Williamson.

Fine particulate matter suspended in the lower atmosphere is regulated by the EPA and is defined as smaller than 2.5 micrometers in diameter. PM2.5 is a public health concern, and leads to reduced visibility. PM2.5 is regulated under the same program as ozone and represents the next major air quality concern in the state of Alabama and throughout the country, especially in urban areas.

Many sources contribute to the PM2.5 concentration, including on- and off-road vehicles, power plants and other industrial facilities. In urban areas, roadways significantly add to PM2.5 concentrations from vehicle emissions and suspended road dust. However, there is very little quantitative information on how much roadways contribute to the local area PM2.5, especially in cities in the Southeast.

“With an enhanced understanding of how road conditions impact the PM2.5 inventory, roadways can be managed to more effectively reduce PM2.5 emissions,” said Williamson.

The research involves various equipment set up along the interstates in Birmingham, including a weather station to record weather (wind speed, direction, humidity, temperature and pressure), a video camera to record traffic, and a particle counter to count the number of particles – (per cc) both upwind and downwind of the road – to see the impact of the road on particle counts.

The team submitted a proposal to the University Transportation Center for Alabama for funding. The UTCA conducts transportation education, research and technology transfer activities using faculty members and students from The University of Alabama, The University of Alabama at Birmingham and The University of Alabama in Huntsville. Other collaborators in this research project include the Jefferson County Department of Public Health, the Alabama Department of Environmental Management, the Alabama Department of Transportation, and the Birmingham Regional Planning Commission.

In 1837, UA became the first university in the state to offer engineering classes and was one of the first five in the nation to do so. Today, the College of Engineering, with about 1,900 students and more than 90 faculty, is one of the three oldest continuously operating engineering programs in the country and has been fully accredited since accreditation standards were implemented in the 1930s.