"Mobile source emissions present a unique public health threat," said Timothy Buckley, PhD, senior author of the study and professor with the School's department of Environmental Health Sciences. "This study provides a unique, real world assessment of the relationship between traffic volume, vehicle class, the weather and curbside concentration of carcinogens. Our findings give us a basis for assessing the public health gains from alternate fuels, control technologies or, best of all, the removal of traffic emissions from our neighborhoods through non-fossil fuel mass transit."
Dr. Buckley and doctoral student Amir Sapkota measured levels of the carcinogens benzene, 1,3-butadiene and PAHs at a tollbooth at Baltimore's Harbor Tunnel over a one week period. Meteorological information and traffic data were also collected and analyzed. Results showed that pollution levels varied 6 to 20 fold depending on both traffic volume and the type of vehicle. The lowest levels were recorded in the middle of the night and the highest levels occurred with the morning rush hour.
Larger vehicles with more than two axles, such as buses, motor homes, and tractor trailers, were found to emit 60 times more PAHs, 32 times more 1,3-butadiene and nine times more benzene compared to smaller vehicles with just two axles. The researchers suggest that the increas
Contact: Tim Parsons or Kenna Brigham
Johns Hopkins University Bloomberg School of Public Health