Slight Degradation

Every year, I write up an annual summary of how California stands regarding the standard measures of air pollution. In general, since about 1980, there has been continued improvement in most air quality measures. Reverses have usually been brief, and haven't always occurred for all pollutants.

There have also been unusual patterns that have revealed themselves over the last 25 years. Air quality has improved dramatically in coastal areas (such as San Diego), but the improvements have been much less dramatic in the interior valleys (like the San Joaquin Valley).

Nevertheless, 2006 was slightly worse than 2005 across most of the range of air pollutants. It may be that population and vehicle-travel growth have finally caught up to the technical improvements that have allowed all of us to breathe fresher air.

I remember, about 1988, in Phoenix, seeing a technical talk by an air pollution expert (can't remember his name anymore) who predicted this very thing would happen, roughly in 2003. With all the seers and prophets and visionaries running around in the world, all trying to predict the future, this guy was the only one I ever met who essentially got the future right.

Or maybe history still has some more tricks to play. After all, this year's pleasant August temperatures will translate into better air quality. And maybe, in regards to air quality improvement, we are all just taking (wait for the pun....) a breather. Only time will tell!

Quoting brief snippets just from the ozone part of the summary:

In the South Coast Air Basin, the peak hourly ozone level in 2006 was 0.175 ppm (recorded at Glendora), down from 0.182 ppm in 2005 (recorded at Crestline). Overall, the 2006 South Coast Air Basin smog season was the fourth-best on record with regard to the federal one-hour standard, and the second-best on record with regard to the state one-hour standard, for ozone.

Peak hourly ozone levels remained down from previous maxima in the San Francisco Bay Area. The peak ozone level in the Bay Area (at Livermore) reached 0.127 ppm, above last year’s 0.120 ppm, but well below 2002’s recent maximum of 0.160 ppm, the highest level recorded in the Bay Area since 1987.

In the Sacramento Valley Air Basin, 2004 was the best year on record regarding violations of the federal one-hour ozone standard, with just one violation. There were three violations in 2005, and seven violations in 2006 (with a maximum of 0.143 ppm at Elk Grove).

The peak hourly ozone concentration in the San Joaquin Valley Air Basin dropped from 0.155 ppm in 2004 to 0.134 ppm in 2005, the biggest year-to-year drop in that air basin in 24 years. In 2006, the maximum peak hourly ozone concentration increased again to 0.141 ppm (at Edison). Nevertheless, 2006 was the San Joaquin Valley’s second-best ozone season with regards to the state one-hour ozone standard.