Sacramento Air Quality

An interactive data visualization of the ozone air quality index values for Sacramento County in recent years.

According to a report by the American Lung Association Sacramento had the 5th most high ozone days out of 277 cities, receiving an overall grade of “F”. Taken at face value without additional context, this sounds alarming. But with some additional information, this generalization it can be seen as a bit misleading. For example, a given county such as Sacramento County will be deemed having a high ozone day if any 1 ozone monitoring station records high ozone for a given day. So, one or two ozone monitoring stations can skew the results of the entire county. The interactive charts below illustrate how two monitoring stations, one in Folsom, the other in Sloughhouse, account for the overwhelming majority of high ozone readings in the area.

The data in the American Lung Association’s report came from the U.S. Environmental Protection Agency’s Air Quality System (AQS) and information obtained was for the 3-year period for 2011-2013, which, as can be seen below has higher number of high ozone days in Sacramento County than in last two years.

AQI Info Box-01Air Quality Index (AQI) values are color-coded as shown on the right. The current national ambient air quality standard for ozone is 0.075 ppm measured over eight hours which corresponds to an AQI value of 100, or yellow. Any day that a particular ozone recording station in the county records ozone over 100 AQI, an orange, red, or purple, the whole county is designated as having had a high ozone day. So, even if you live near the Sacramento T Street station which often has zero days of high ozone in a year, if the Folsom station records a high ozone day, using the criteria used by the American Lung Association, you’ve been deemed as having one as well. Explore the charts below for the different monitoring stations over the years to see how your area’s air quality has fared over the years.

Data from the EPA.


2014 Station Totals

2014 Station Exceedances

2014 Daily Readings


2013 Station Totals

2013 Station Exceedances

2013 Daily Readings


2012 Station Totals

2012 Station Exceedances

2012 Daily Readings


2011 Station Totals

2011 Station Exceedances

2011 Daily Readings


2010 Station Totals

2010 Station Exceedances

2010 Daily Readings


2009 Station Totals

2009 Station Exceedances

2009 Daily Readings

Sacramento AQI Monitoring Stations Map