sentence1: The 2010 and 2020 Clear Skies Act profile includes a 4.5 million ton/year cap on EGUs beginning in 2010 for SO2 emissions, which will be lowered to a 3 million ton cap in 2018; a 2.1 million ton/yr cap beginning in 2008 for NOX emissions, which will be lowered to a 1.7 million ton cap in 2018; and a 26 ton/yr cap beginning in 2010 for mercury emissions, which will be lowered to a 15 ton cap in 2018.
sentence2: This act has caused air pollution to fall by 5% each year since it was initialized.