Nox emissions contribute to nitrogen deposition that may lead to eutrophication of estuaries and near-coastal waters and can damage forested watersheds.
The United States is the number one Nox emitter. 
mnli hypothesis: The United States is the number one Nox emitter.  premise: Nox emissions contribute to nitrogen deposition that may lead to eutrophication of estuaries and near-coastal waters and can damage forested watersheds.