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.