Studies performed in large inner-city areas (specifically Chicago, Detroit, Pittsburgh, and Birmingham) show that the turbulence created by traffic causes airborne
contaminants to be dislodged into the air we breathe. Lead was previously used in the manufacture of gasoline and other petroleum products between 1923 and 1995 in the United States, and previous testing showed that the roadside soil, especially in urban areas, contains very high levels of lead.
The recent study, conducted and published by PhD candidates in several leading universities indicates that lead and soil become aerosolized when continually disturbed and airborne contaminants are more easily ingested by people who live in or near these heavily-traveled, large urban centers.
Older inner-city areas are at particularly high risk for accumulations of lead and soil along roadsides, and this study is particularly alarming because it was previously assumed that urban public health risks were lessened by these contaminants stabilizing with age. This January 2012 study shows that these airborne contaminants are in fact re-suspended, making them more readily breathed in and absorbed into the bloodstream, potentially leading to lead poisoning. The studies further showed the most re-suspension of particulates is during busy travel periods, such as holidays and weekends.
This study has implications for the United States as well as other industrialized nations that prior use of lead-containing petroleum products will have a long-term effect on at-risk populations, particularly in urban areas, and monitoring in conjunction with remediation will most likely be an international endeavor.