That headline seems purposely misleading. If you actually read the article, it claims that electric cars are worse if powered by a coal plant at the other end. Buried further down, it says, "But if the power supply comes from natural gas, the all-electric car produces half as many air pollution health problems as gas-powered cars do. And if the power comes from wind, water or wave energy, it produces about one-quarter of the air pollution deaths."
In my state, NJ, virtually all of our electricity comes from an even split between nuclear and natural gas.
Further, the claim about electric cars being dirtier than gasoline cars when all the energy comes from coal is highly suspect. Other studies have come up with numbers that show an electric car on coal power is roughly on par with gasoline cars in terms of being "clean". Given that (as this article states) 39% of the U.S.'s electricity comes from coal, and that number is steadily dropping, it's not hard to see that EV's are already an overall plus, and will get better as the grid gets cleaner. Gasoline and diesel cars just get worse with age, and I question 2 related things: 1) are cold start emissions taken into account?; 2) a study from not too long ago in Europe suggest that diesel manufacturers "game" the test (tuning their emissions performance to match the known test procedure), and in the real world have not dropped nearly as much in pollution from diesels of a decade ago as the standards might suggest.
Finally, for any such study to be credible, it has to clearly account for the energy needed to extract and ship oil, refine to gasoline, and ship to filling stations. Estimates I've seen are that each gallon of gasoline requires 6 to 7 kW/h of energy just to refine, enough energy by itself to power a Chevy Volt about 20 miles. I seriously doubt the study in this article took any of that into account to come up with claims that contradict not only previous findings, but common sense.