Comparing the Progress of two Air Boards

Forget about cherry-picking data for a minute.  The two EPA designated air basins in the United States with the most air pollution are the San Joaquin Valley and the South Coast (Greater Los Angeles Region).  Each area has been measuring PM 2.5 levels since 1999.  Both areas have made some improvement.  The standard both are trying to reach is an annual average of 15 micrograms per cubic meter.

The graphs of the annual averages for each air basin tell a story.  The data can be averaged with linear progression to show the trend.  As stated, both areas have improved overall.  But, one area has improved more than the other.

The facts are, the South Coast area started with higher levels in 1999 when compared to the SJV.  They have reached a point where the trend today shows the South Coast below the SJV (even though the actual average for 2011 has the South Coast slightly higher).

We can show several things from the data.  The SJV was 12% cleaner than the South Coast in 1999 and has ended up 18% more polluted in 2011.  The South Coast has improved by 24% and the SJV by 13% over this same time period.  The South Coast, if their rate of improvement continues, will reach compliance with the standard in about ten years.  The SJV will need more than 20 years.

Conclusion:  the Air Board in the SJV is not doing as good a job as their counterparts in the South Coast.  Some reorganization is definitely in order.

7 thoughts on “Comparing the Progress of two Air Boards

  1. The South Coast has a table at the Smart Growth Conference in San Diego. They have tons of resources for folks, I especially like their brochure on “The Health Effects of Air Pollution.” One of the handouts was a very easy to understand Air Quality Index that uses the color system. Is our District the only one that changed to a number system?

  2. What values are depicted on the vertical axis?

    It’s depressing to think of the damage that will have been done to the lungs of a child born this year by the time they are twelve years old, but can’t one take some solace in ARB’s diesel emission regulations, even though they’re so slow to be implemented?

  3. The comparison you display is accurate, but I think your vertical axis is mislabeled.
    These are numbers from ARB.

    PM 2.5 Trends Summary: San Joaquin Valley
    Annual Average (Nat’l) µg/m3)

    2010 17.9
    2009 22.5
    2008 23.5
    2007 22.0
    2006 19.3
    2005 19.8
    2004 18.9
    2003 19.6
    2002 24.1
    2001 22.5
    2000 23.9
    1999 27.6

      • Did you have some reason for shunning the ARB numbers, other that wishing to include 2011, and are there South Coast measures to which you would attribute their swifter progress?
        I sometimes wonder if we are slowed because dirtier vehicles come to the valley to retire — active retirement — except the posh ones in Jay Leno’s collection.

  4. ARB numbers are based on individual sites. I don’t know the exact protocol they use. I still think my method of comparison is valid. I may also compare individual sites like Riverside and Bakersfield over the same years but then missing data can be problematic.

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