Daily, approximately 321,000 underfired charbroilers in approximately 700,000 U.S. food service operations account for 94 percent of current restaurant emissions, equivalent to more than 285 tons of particulate matter (PM) and more than 41 tons of volatile organic compounds (VOCs), a significant source of environmental air pollution adversely impacting health. Grease emissions from one underfired charbroiler are approximately 2.15 MT/yr.
http://cfpub.epa.gov/ncer_abstracts/index.cfm/fuseaction/display.abstractDetail/abstract/9132