CATS: Decline in smog-forming emissions from California cars a bright spot

Number seven in the Clean Air Technologies Series.

In a 1952 “Key Events in the History of Air Quality in California” entry, the California Air Resources Board (ARB) revealed, “Dr. Arie Haagen-Smit discovered the nature and causes of photochemical smog. He determines that nitrogen oxides and hydrocarbons in the presence of ultraviolet radiation from the sun forms smog (a key component of which is ozone).” Imagine that very discovery dating to 1952. In case you didn’t already do the math, that’s 60 years ago. The listing chronicling key historic air-quality-related information from California and around the globe goes all the way back to 1930.

A more recent ARB entry from the same source reads: “Federal Air Pollution Control Act of 1955 was enacted, providing for research and technical assistance and authorizing the Secretary of Health, Education and Welfare to work towards a better understanding of the causes and effects of air pollution.”

Next stop, 1961, and “The first automotive emissions control technology in the nation, Positive Crankcase Ventilation, was mandated by the California Motor Vehicle State Bureau of Air Sanitation to control hydrocarbon crankcase emissions. Positive Crankcase Ventilation withdraws blow-by gases from the crankcase and returns them with the fresh air and fuel mixture in the cylinders,” noted the California air regulatory agency.

Biodiesel-powered bus
Biodiesel-powered bus

In 1966, meanwhile, “Auto tailpipe emission standards for HC and CO were adopted by the California Motor Vehicle Pollution Control Board. First of their kind in the nation.” The acronyms HC and CO stand for “hydrocarbons” and “carbon monoxide,” respectively.

And finally, a dozen-and-a-half years later – 1984 – is when the “CA Smog Check Program went into effect identifying vehicles in need of maintenance and to assure the effectiveness of their emission control systems on a biennial basis,” the ARB noted.

What all this has led up to is what my responsibility as a California registered motor vehicle owner entails as it relates to smog certification requirements.

In the Golden State, every two years a vehicle smog certification is required for registered vehicles unless exempted. According to the California Department of Motor Vehicles, exempted are:

  • Hybrid
  • Gasoline powered 1975 year model or older
  • Diesel powered 1997 year model and older or with a Gross Vehicle Weight rating (GVWR) of more than 14,000 lbs
  • Electric
  • Natural gas powered with a GVWR rating of more than 14,000 lbs.
  • Motorcycle

Meanwhile, the last time I had my car smog certified was in Jan. 2012. Pollutants tested for are carbon dioxide (CO2), carbon monoxide (CO), hydrocarbons (HC) and nitrogen oxides (NOx).

At this moment in time and for purposes of this discussion, I am interested in knowing how my car stacks up emissions-wise, so I chose to use test year 2007-’08 as an example.

In late 2007, for 2008 vehicle registration purposes, at 15 mph and 1939 rpm, %CO2 measured was 15.3, HC in parts per million (PPM) was 1, %CO was 0.0 and NOx was 2 PPM. At 25 mph and 1939 rpm %CO2 was 15.3, HC was 0.0 PPM, %CO was 0.0 and NOx was 0.0 PPM.

All measurements were within specifications so the vehicle passed and was therefore smog certified.

Ozone (O3), a main ingredient in smog, from the motor vehicle sector in California has been on the decline invariably as a result of initiatives such as the state’s Smog Check and other programs. But, by no means does this mean smog coming from the transportation sector is no longer problematic in state.

Case in point: In the Public Policy Institute of California report: “Planning for a Better Future: California 2025: 2010 Update,” report authors Louise Bedsworth and Ellen Hanak in the section dealing with “Transportation” write: “Heavy-duty vehicles (trucks and buses) and off-road sources (construction equipment, trains, farm equipment, and the like) are now the largest contributors to transportation-related smog-forming emissions. These sources have been less-regulated than passenger vehicles, and their emissions have been growing. A leading source of growth is increased goods movement through the state’s ports and along its freeways. New regulations set tighter emission standards for on- and off-road heavy-duty vehicles, and efforts are under way to reduce emissions from the state’s ports.”

And related to this elsewhere in the report in question and in an illustration comparing years 1975 and 2006 and depicted in the form of a graph, in 1975, motor vehicles in state were responsible for 70 percent of all smog-forming emissions coming from the mobile-source sector, whereas 30 percent of such were from heavy-duty vehicles and off-road and other mobile sources. In 2006, the tables turned: passenger vehicles produced roughly 25 percent of smog-forming emissions and heavy-duty vehicles, off-road and other mobile sources were responsible for the remainder or about 75 percent.

Advancements in the automotive realm, traffic management techniques and infrastructure design, and improvements made to fuels along with new fuel blends, will go far and do much to further reduce smog-forming pollutants emitted from automobiles as well as from other mobile sources.

Leave a Comment