Rachel Gasparini


Failing Air Quality Standards in California

Air pollution is rising to dangerous levels all over the world, the United States being no exception. Data from the most recent reports shows that California has the worst air quality out of every state in the U.S.

In the State of the Air 2015 Report, the American Lung Association (ALA) ranked the most polluted and the cleanest U.S. cities by year-round particle pollution (annual PM 2.5).  The most recent comprehensive data was collected from 2011 to 2013 to find the annual average of PM 2.5.

10 U.S. Cities Most Polluted by Particle Pollution

Worst Polluted Cities

10 Cleanest U.S. Cities for Particle Pollution

Cleanest Cities

California is responsible for seven out of ten of the most particle polluted cities in the U.S.  The state only accounts for one out of ten of the cleanest cities for particle pollution.

The U.S. Environmental Protection Agency’s (EPA) 2014 Design Value Report analyzes particle pollution levels of every state, but the following visual was made by extracting data solely from California.  The annual mean of particulate pollution (PM 2.5) from 2011 to 2013 was collected in each county.  Out of the entire state, Central California is most polluted by PM 2.5, the highest counties being Madera, Kern, and Kings.

The state has consistently been plagued by some of the worst air quality in the country for years.  Every county shown above exceeded the average standard level of PM 2.5, which is 12 mg/m3.  Based on this, the ALA gave every county pictured a failing air quality grade.

PM 2.5 is a very tiny particle – the width of a single particle is often thirty times smaller than that of human hair.  The California Environmental Protection Agency lists known sources for PM 2.5 while the ALA identifies the potentially adverse health affects of particle pollution.

In the case study above, data from California Health & Human Services on 2012 Asthma ER Visits was cross-referenced to the average amount of PM 2.5  in the ten cleanest counties and ten most polluted counties in California.  The U.S. Census Bureau records of county populations in 2012 was also used. While other factors may be at play, this combined data shows a possible correlation between asthma and PM 2.5 levels. On average, twenty-two more people (per 10,000) visited the ER for asthma in the most polluted counties over the cleanest counties in California.

To learn more, see what the air quality is like in your area with AirNow and compare it to the counties in California.