Well if you're hoping for a Rolling Stones song here you may be disappointed. However the United States Geological Survey (USGS) assembled their own "band" of experts to look at air quality and runoff quality of a freshly sealed coal tar parking area.
These researchers have been creatively working on this issue for more than 8 years now. Generally they have found that coal tar sealants contain high amounts of polycyclic aromatic hydrocarbons (PAH), and they are mobile in runoff, air volatilization, wind, and tracking by shoes and tires.
The above video is shorter than the second, but they cover similar material. If you want the detailed explanation of the science and sampling, then I would suggest the second video. Enjoy!