“Particulate matter causes premature death. It doesn’t make you sick. It’s directly causal to dying sooner than you should,” former EPA administrator Lisa Jackson told Congress on Sept. 22, 2011. “If we could reduce particulate matter to healthy levels it would have the same impact as finding a cure for cancer in our country.” 

So basically the EPA wants to give people cancer in order to prove cancer exists. I can't think of any other reason the EPA would subject human beings to particulate matter in live trials.

Read more: http://dailycaller.com/2014/04/02/report-epa-tested-deadly-pollutants-on...

http://dailycaller.com/2014/04/02/report-epa-tested-deadly-pollutants-on...
http://www.scribd.com/doc/215909101/EPA-Human-Study-Subjects

Improvements to EPA  Policies and Guidance Could Enhance Protection of Human Study Subjects 
Report No. 14-P-0154 March 31, 2014