The smoky flavor

When an estimated 60 million Americans fire up their barbecue grills this Fourth of July, they’ll be burning the equivalent of 2,300 acres of forest and consuming enough energy to meet the residential demand of a town the size of Flagstaff, Ariz., for an entire year.
Tristram West of the Department of Energy’s Oak Ridge National Laboratory also calculated that the grills would emit nearly 225,000 metric tons of carbon dioxide. A metric ton is equal to about 2,200 pounds. West’s estimate includes carbon dioxide emissions from production and combustion of the fuel. Carbon dioxide, considered a greenhouse gas, is increasing in the atmosphere each year and is thought to be a major factor in climate change.
July 4 is by far the most popular day of the year for cookouts, according to a Hearth, Patio & Barbecue Association ( survey that found that 76 percent of the nation’s grill owners use at least one of their grills that day. The survey also found that 76 percent of American households own a grill and 42 percent own more than one. Sixty-one percent own a liquefied petroleum gas grill; 48 percent own a charcoal grill; 9 percent own a natural gas grill; and 7 percent own an electric grill.
West, a researcher in ORNL’s Environmental Sciences Division, assumed a 35,000 British thermal unit per hour output for the average grill and one hour of operation for each grill. In making his calculations, West took into account the carbon content and carbon dioxide emissions for each type of fuel.
“While more grills are fueled with liquefied petroleum gas, the majority of carbon dioxide emissions are from grills using charcoal briquettes, because the amount of carbon per Btu of gas is about one-third that of charcoal,” West said.
Although electric grills emit no on-site carbon dioxide, West said they have the highest emissions per hour of all the grills when accounting for fossil fuel emissions from producing and transmitting electricity. A liquefied petroleum gas grill operated for an hour would emit 5.6 pounds of carbon dioxide while a charcoal grill would emit about 11 pounds. An electric grill would account for about 15 pounds of carbon dioxide.

The smoky flavor and the char that one gets from a well-grilled steak is not particularly good . ( ). When fat from the cooking meat drips down on the hot coals, the smoke that forms contains stuff called polycyclic aromatic hydrocarbons (PAH)( ). And the charred exterior of the meat (or inside, if you like things extremely well-done) is chock full of something called heterocyclic amines (HCA). Exposure to high levels of HCAs and PAHs can cause cancer in animals; however, whether such exposure causes cancer in humans is unclear.
Currently, no Federal guidelines address consumption levels of HCAs and PAHs formed in meat.
HCA and PAH formation can be reduced by avoiding direct exposure of meat to an open flame or a hot metal surface, reducing the cooking time, and using a microwave oven to partially cook meat before exposing it to high temperatures.
Ongoing studies are investigating the associations between meat intake, meat cooking methods, and cancer risk.
Both of these have been linked in studies, like one conducted by the National Cancer Institute in 1999, to higher rates of colorectal cancers, and both chemicals have been added to the DOH’s official list of carcinogens (PAH all the way back in 1981, HCA in 2005). In 2009, another study found that people who preferred their steaks “very well done” were 60 percent more likely to get pancreatic cancer than those who liked them bloody (or didn’t eat steak at all), and both compounds have been found to cause tumors in mice (and might cause even more tumors in humans, since mice process the chemicals differently).