Folks in the comments are making assumptions about what's in the Constitution, so I decided to go take a look. If I were the petitioners, I'd point to section 1 of the 14th Amendment:

No State shall make or enforce any law which shall abridge the privileges or immunities of citizens of the United States; nor shall any State deprive any person of life, liberty, or property, without due process of law; nor deny to any person within its jurisdiction the equal protection of the laws.

Depriving someone of clean air to breathe is depriving them of life. The medical conditions from being exposed to unclean air threaten property through medical bills in a country without universal healthcare. And finally, liberty cannot exist without life.

And since a lot of folks are going for the technically correct legislative analysis, remember that bad air causes autoimmune disorders, and thus abridge the immunities of the citizens of the United States. A stretch, but I'd say it qualifies if you're analyzing the law from a purely textual standpoint.

Can I just say I absolutely love the 14th amendment? It's not the Declaration of Independence, but it does a lot of heavy lifting for it in the Constitution.