Looking for clean air and lots of greenery? Los Angeles is probably not the first place that comes to mind.

Still, the city as famous for traffic and smog as it is for sunshine and celebrities is working hard to earn the mantle of the greenest big city in America.

In its latest move, the L.A. City Council this week passed a law that will require all new building projects bigger than 50 units or 50,000 square feet to comply with the Leadership in Energy and Environmental Design (LEED) building standards. The city claims the move will cut its carbon dioxide emissions by 80,000 tons by 2012 — the equivalent of taking 15,000 cars off the road.

Mayor Antonio Villairagosa says the goal is the most aggressive of any big U.S. city. It is part of a broader plan the mayor laid out last year to reduce L.A.’s carbon footprint by 35 percent below 1990 levels by 2030.0

Still, critics point out that L.A.’s plan is not as aggressive as the one being pursued up North, in San Francisco — a debate the “Los Angeles Times” chronicled on Tuesday. In the story, advocates said L.A.’s move will have more of an impact on the environment because it covers so much more ground than San Francisco.

In the meantime, L.A. might have to take on an even bigger challenge — convincing the public that it can really go green.

As one LAT reader commented: “Los Angeles green? Only with paint.”