AQ Monitoring Results:
Crockett: 1,3-Butadiene at John Swett
This page last reviewed September 27, 2010
One of the important contributors to health risk, 1,3-butadiene is a flammable, colorless gas with a pungent, aromatic, gasoline-like odor. 1,3-butadiene vapors are mildly irritating to the eyes and mucous membranes. They can cause neurological effects such as blurred vision, fatigue, headache, and vertigo at very high levels. The ARB has identified 1,3-butadiene as a toxic air contaminant based on its potential to cause cancer. California has determined under Assembly Bill 1807 and Proposition 65 that 1,3-butadiene is a cancer-causing compound.
In California, the majority of emissions are from incomplete combustion of gasoline and diesel fuels. Mobile sources account for approximately 96% of the total annual emissions statewide for quantified sources. The primary stationary sources of emissions are petroleum refining, manufacturing of synthetics and man-made materials, and oil and gas extraction. In nature, 1,3-butadiene is emitted as a product of incomplete combustion during forest fires. 1,3-butadiene emissions have been reduced in California through motor vehicle emission control regulations and the introduction of cleaner burning gasoline. In the1990s, the ambient 1,3-butadiene levels showed a steady downward trend, based on the statewide annual average. The 2000 statewide ambient 1,3-butadiene concentration was approximately 53% lower than that in 1990.
Ambient Monitoring Results
Ambient levels of 1,3-butadiene are routinely monitored at approximately twenty sites in the California air toxics monitoring network. The statewide average concentration of 1,3-butadiene during 1998-2000 was 0.2 ppb (parts per billion), with values ranging from 0.1 ppb to 3.0 ppb. The current routine monitor closest to Crockett is in Fremont. Relative to the statewide average, the Fremont region was 10% lower, with an average concentration of 0.18 ppb for the same time period.
The ambient monitoring results at John Swett are provided here:
- A graph comparing the monthly summaries of 1,3-butadiene at the community with historical statewide and regional levels
- A table of summary statistics
- Raw data in Excel format
Cancer risk is the number of excess cancer cases among a million people if the people are exposed to levels of a toxic air pollutant over 70 years. 1,3-butadiene represents approximately 20% of the potential cancer risk of the nine measured compounds, excluding diesel particulate matter. 1,3-butadiene represents approximately 4% of the potential cancer risk of the nine measured compounds and the estimated diesel particulate matter.