Almost everyone’s been embarrassed at one time or another by an over-eager dog sniffing in the wrong places. Now car owners have to worry about the “smog dog,” designed to “sniff” tailpipes to detect air pollution. Formally called the AccuScan Remote Vehicle Emissions Testing System, the smog dog analyzes exhaust from cars as they pass roadside monitors. A camera adjacent to the smog sensors takes pictures of the cars’ license plates, and the owners are notified of the results. Polluters are hauled in for an official emissions inspection, while in some states, owners of very clean cars get a letter of congratulations waiving their next emissions appointment. Smog dogs are already in use in several Western states and are currently being tested in Virginia, which could face sanctions from the U.S. EPA if it can’t clean up its air. Most of the pollution in that state is from vehicles, and of that, 10 percent of the cars account for 50 percent of the pollution.