When choosing a grill, keep in mind that gas grills are greener than charcoal grills, which emit nearly three times the carbon. If nothing but that charbroiled flavor will do, at least skip the briquettes and go for lump charcoal (or natural charcoal). Standard briquettes are made from compressed wood by-products and contain additives, such as borax and sodium nitrate, that contribute to smog-forming pollution. Lump charcoal made from hardwood contains no additives and burns cleaner. You can also use lump charcoal ash to alkalize garden soil (a no-no for briquette ash). Keith Snow, author of The Harvest Eating Cookbook, recommends Cowboy All-Natural Lump Charcoal ($6.1 for an 8.8-pound bag), available at Amazon.com.