A new report lists the most polluted cities in the Los Angeles , including several Los Angeles cities . David Pettit : There are too many cars and trucks , oil refineries and industrial facilities . He says California , for example , needs to massively expand its public transit system . Pettit : Just like ozone , fossil fuel combustion at power plants and by cars and trucks plays a major role in its production . California needs to accelerate development of clean , renewable energy .
A new report lists the most polluted cities in the Los Angeles , including several Los Angeles cities . David Pettit : There are too many cars and trucks , oil refineries and industrial facilities . He says California , for example , needs to massively expand its public transit system . Pettit : California needs to accelerate development of clean , renewable energy .