“If you tell a lie big enough and keep repeating it, people will eventually come to believe it. The lie can be maintained only for such time as the State can shield the people from the political, economic and/or military consequences of the lie. It thus becomes vitally important for the State to use all of its powers to repress dissent, for the truth is the mortal enemy of the lie, and thus by extension, the truth is the greatest enemy of the State.” – Joseph Goebbels 
Apparently, the EPA has learned a lot from Mr. Goebbels. They continue to campaign against PM2.5 air pollution on the notion that, in the words of former EPA Administrator Lisa Jackson “Particulate matter causes premature death. It doesn’t make you sick. It’s directly causal to dying sooner than you should.”
Not only does ANY level of PM2.5 cause premature death (even the ambient level we breathe in “clean” air), it causes it within 0 to 1 days of exposure! That’s right, you could die from breathing today!
Of course, the current conditions in China put this lie to the test. People in China should be dropping dead by the extra thousands. In 2014, estimates were that all air pollution was causing 17% of deaths each year in China. Of course, that is dwarfed by the 24% of deaths it causes in America (Lisa Jackson, in testimony before Congress, said that the regulations on PM2.5 would be the equivalent of “curing cancer.” Cancer causes approximately 570,000 of the 2.4 million annual deaths in America.) I’m thinking those Chinese are really tough.
Of course, what will happen if there isn’t a spike in deaths in China? Nothing. Will the EPA rethink it’s entire attitude? No. Their death estimates are based on “models” which – of course- are immune to physical evidence. Even their own experiments on immune-compromised and elderly people – experiments where they basically said “Here, suck on this diesel engine tailpipe” – didn’t have people dropping dead from PM2.5 exposure. The consent forms didn’t even mention “You may, according to our testimony before Congress, DIE within hours or days of these experiments.” 
Truth be told, PM2.5 may have a threshold level of impact, but nobody, not even the EPA, believes that it will kill you within hours of inhalation, regardless of their own lies. The Chinese are currently LIVING proof of that.