Chevrolet Volt "Low Emissions Package"

"Low Emissions Package"? – It's a secondary air-injection pump that adds air to the exhaust system to improve the catalytic converter's ability to remove pollutants.

In California, this is good news because vehicles fitted with this package can get access to high-occupancy-vehicle lanes as well as a $1,500 state rebate.

http://carscoop.blogspot.com/2011/11/chevys-low-emissions-package-gives-2012.html?m=1