Here's some good data for the Los Angeles area: http://www.aqmd.gov/smog/Forecast.htm http://www.aqmd.gov/smog/Forecast.htm http://www3.aqmd.gov/webappl/aqdet

Here's some good data for the Los Angeles area: http://www.aqmd.gov/smog/Forecast.htm http://www.aqmd.gov/smog/Forecast.htm http://www3.aqmd.gov/webappl/aqdetail/AirQualityParameterData.aspx?Stationid=70087&AreaNumber=1&res=1152 http://www3.aqmd.gov/webappl/aqdetail/AirQualityParameterDat... Click on "Historical Data" to create a graph. Bottom line, LA seems to hover around 25 µg/m³.