Scientific transparency

One of the significant concerns surrounding the proposed "science transparency" changes at the EPA has to do with revisiting older "pivotal regulatory" science, for example, the "Harvard Six Cities" study that set the stage for air pollution standards. That paper is now over 25 years old; you have to wonder how it has withstood the test of time. Let's take a look. 
The “pivotal regulatory science” used in setting air pollution standards are epidemiologic studies measuring the effects of particulate matter (PM) on our health. The recently proposed changes to improve the transparency of regulatory science at the EPA have brought them to the forefront.
A revised proposal, regarding scientific transparency in the EPA's regulatory decisions, has raised concerns about casting more shade than light. What exactly is being proposed, and why the concern?