The air in Los Angeles has been extremely yucky for the past two days. Looking off into the distance -- towards downtown -- a layer of thick brown smog hugs the ground. Maybe that's what foreigners would stereotypically expect from the City of Angels, but the air here is usually pretty good... as long as there's wind from the ocean. Unfortunately, the winds are blowing from the east and bringing smog from inland, rather than Mary Poppins.
The BoiFromTroy comments that the increased smog may be due to the ban on MTBE that took effect on January 1st. MTBE is an oxygenating additive that's used in gasoline to help it burn more cleanly, and it was banned because of "concerns" that it pollutes groundwater. This is an interesting possibility, but it looks like oil companies began phasing out MTBE in 2002 and 2003 (the ban was originally supposed to start in 2003). Federal law requires that gas be 2% oxygenator by weight, and ethanol can be used in place of MTBE but I don't know if it has the same level of effectiveness.