Consider this: the act of driving a vehicle is the average person's one regular activity that has the single largest impact on the earth regarding climate change. Indeed, for each gallon of gasoline burned, that’s nearly 20 pounds of heat-trapping carbon dioxide released into our atmosphere, not to mention carbon monoxide, oxides of nitrogen, sulfur—and more. And here come the numbers: Every 1 million gallons of gasoline consumed by vehicles releases approximately 10,000 tons of carbon dioxide into the atmosphere. Consider the fact that the United States uses approximately 420 million gallons of gasoline per day. Indeed, it's estimated that the United States releases over 8 billion pounds of carbon dioxide into the atmosphere per day—and this is just from gasoline.
You are right that the main goal is for air pollution, but air pollution greatly contributes to global warming
Anyways back to the original topic