A California air quality progress report

California is home to approximately 38 million people.

According to the California Air Pollution Control Officers’ Association (CAPCOA) April 2012 “California’s Progress Toward Clean Air” report: “California, the most populous state in the nation, includes regions with pristine air quality as well as regions with the highest number of violations of the federal health-based standards for ozone and particulate matter. California employs a comprehensive strategy aimed at reducing pollutants from a variety of sources of air pollution. This multifaceted strategy targets mobile and stationary sources of pollution emitting myriad air contaminants and contains effective regulatory and incentive-based measures. Local air districts have authority to regulate businesses and industrial facilities, while the California Air Resources Board (CARB) regulates pollution from cars, trucks, buses and other sources.”

The two regions with the highest concentrations of ozone and particle pollution are the South Coast and San Joaquin Valley air basins.

CAPCOA, in its 2012 report, provides summary data regarding each of the state’s 35 air districts.

In the San Joaquin Valley, for example, during summer 2011, there were far fewer ozone exceedance days of the federal one-hour standard (a total of three) than there were in both 1996 when there were 56 and in 2002 when the Valley experienced 30. And with the addition of four new monitors for tracking and recording area ozone levels, the previous three years saw the lowest number of total federal eight-hour standard violations.

Regarding Valley wintertime particulate levels, the combined eight-county San Joaquin Valley recorded 15 exceedance days during the 2011-’12 season, up from just two the previous winter. A greater mixing of the air during the 2010-’11 season might have been a contributing factor all other conditions being equal. CAPCOA did, however, express that “There was also a substantial change in the number of exceedances of federal, health-based, air quality standards for PM2.5 this winter season relative to last season. Last year, Valley counties had a total of 47 combined exceedances of the federal standard during the winter season, with this year’s total at 62 combined exceedances.”

Keep in mind that California’s ambient air quality standards for ozone and fine particulates are more stringent than national standards for the same. It is important to note, however, that the federal standard for fine particulates to go into effect in 2020, will be 12 micrograms per cubic meter of air; an upgrade from the 15 micrograms per cubic meter of air in effect currently.

Meanwhile, in the South Coast region, CAPCOA emphasizes: “While [Air Quality Management District] continues to see a trend of improving air quality, there are still major challenges for the region, particularly in reducing mobile source emissions. Emissions of nitrogen oxides (NOx) must be further reduced by more than 60 percent to meet current federal health-based air quality standards for ozone and fine particulates.”

There is good news. Regarding statewide stationary sources marked reductions in both reactive organic gas (ROG) and nitrogen oxide (NOx) emissions have been realized. CAPCOA data show that ROG fell from roughly 1,700 emitted tons daily in 1980 to about 425 tons in 2011. Trending similarly were emissions of NOx which went from approximately 1,175 tons per day to slightly less than 400 in 2011.

For ROG from mobile sources across the state, there was similar improvement. However, for NOx, although improvement did occur, the gain was not nearly as dramatic as far as NOx emissions are concerned compared to release of said emissions from stationary sources.

Case in point: From California mobile sources, ROG in 1980 was around 4,200 released tons per day and in 2011 those emissions were down to just under a thousand daily tons. As for NOx, this emission dipped from roughly 3,600 tons daily to approximately 2,400 tons per day.

Statewide, the numbers for fine particulate matter pollution (PM 2.5) improved as well.

From stationary sources, PM 2.5 emissions dropped from around 165 tons per day in 1980 to a skosh below 100 in 2011 and from mobile sources statewide, PM 2.5 went from approximately 138 tons daily to 130 tons per day.

Of particular note is that regarding NOx and VOC (or volatile organic compounds) combined, the trend statewide from 1980 to 2005 was negative, meaning there was a decline from around 11,500 daily tons to about 6,000 tons per day, respectively, a difference of approximately 5,500 tons or an improvement of roughly 92 percent. During that same period of time, California vehicle miles traveled rose from about 400 million per day in 1980 to about 950 million in 2005.

CAPCOA indicated that improvement occurred despite there being no local or state authority to regulate air pollution from aircraft, locomotives and ships, which are federally controlled.

So, to try to summarize, improvement statewide in aforesaid emissions has been realized. Even so, the South Coast and San Joaquin Valley air basins continue to be in violation of the federal health-based standards for both summertime ozone and wintertime PM 2.5.

Although I was not able to find this information in the report, as much as a third of the state’s population resides in the southern California region. San Joaquin Valley population, meanwhile, is projected to grow from roughly 4 million people currently to 6 million by 2050. State population, on the other hand, is projected to jump to between 50 million and 60 million people by mid-century. It is also anticipated that 80 percent of total statewide population will live in cities meaning the remaining 20 percent will reside in rural areas.

My own sense is that much more aggressive air pollution-mitigating strategies must be initiated in many areas around the state and in particular in the South Coast and San Joaquin Valley air basins if there is to be continued marked improvement.

That being said, CAPCOA points out that “Clearly, California’s clean air strategies continue to serve as a model for the rest of the nation and throughout the world.”

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