You may not have known (because it's kind of inconceivable), but the EPA hasn't been regulating carbon dioxide thus far because the agency didn't regard it as a pollutant-despite the fact that it damages our environment and the health of the people in it.Today that changed. The EPA announced that it has found that carbon dioxide (along with a handful of other greenhouse gases) poses a threat to public health and contributes to climate change.Kate Sheppard at Grist has the details:"There will be a 60-day public comment period on the EPA finding itself, after which it will be entered in the Federal Register, the government's official publication for rules and regulations. The agency would then be legally required to start regulating CO2 emissions, though the EPA can decide the timing, sequence, and scope of any regulations.The EPA could regulate a wide range of polluting entities, but the agency is likely to focus first on two main sources of pollution: cars and stationary pollution points like power plants and major industrial sources, including chemical and cement manufacturers."So it's unclear exactly how this will be implemented. Sheppard says that we could get uniform (tighter) emissions standards for cars as early as August. But the point is we now have the EPA as an ally in our collective effort to keep the world in decent shape for humanity.You can get all the dry primary documents and find out how to take part in the public comment process over at the EPA site.