1. Whether, as the Fifth Circuit has held, a plaintiff in a CAA citizen suit may satisfy Article III's traceability requirement merely by showing that she suffered the "kinds of injuries" that defendants' conduct "could have" caused.

2. Whether this Court should overrule its holding, in Friends of the Earth, Inc. v. Laidlaw Environmental Services (TOC), Inc., 528 U.S. 167 (2000), that the availability of civil penalties paid to the government can satisfy Article III's redressability requirement for private, citizen-suit plaintiffs.

Whether a plaintiff in a Clean Air Act citizen suit may satisfy Article III's traceability requirement by showing potential injuries and whether civil penalties paid to the government can satisfy redressability requirements