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This map, created by ProPublica, "highlights areas where the additional cancer risk is greater than 1 in 100,000 — 10 times lower than the EPA’s threshold, but still high enough to be of concern, experts say."
"CSL studies the processes that influence air quality on local, regional, and global scales to support informed air quality decision-making at local, state, national, and international levels."
Air Pollution Control Equipment Selection Guide by 
Criteria Air Pollutants and Their Impact on Environmental Health by 
Indoor Air Quality : The Latest Sampling and Analytical Methods by 
Wentworth
Institute of Technology