And a wonderful principle it is: we all paid for those roads, but soon only those who can afford to do so can use them. Bleah. Why not just close the streets of Manhattan off to everyone except busses, commercial trucks, and taxis? Oh right, because the subway only serves the 'meaty' parts of the island and people who would love to sit in judgement of the personal behavior of millions of people who don't have much of a choice in the matter give only lip service to providing high quality comprehensive public transit city-wide, not just in the major shopping districts.
This all presumes that it's not already incredibly expensive to drive in Manhattan, and completely ignores things like: parking (hey, $25/hr at Rock Center, fun! Did you see that article about parking spots being more expensive square-footage-wise than the condos they are attached to?), temptation to try to park illegally and getting towed, damage from poorly maintained streets and nearly nonstop construction, existing tolls, etc. What makes youse think adding another few dollars will clean the air?
You want a law that will clean the air? Pass one that forces Con Ed to scrub the cola plants better. Pass one that requires car companies to sell cars and trucks with higher mileage and emmission standards.
/jordan