Diesel Exhaust Pollution

One major issue with the mine reopening is the increase in large trucks into and out of the mine area. This traffic exposes GV and Nev Cnty to significantly increased traffic, noise, CO2 and especially pollution. The following article outlines the major issues with diesel emissions. This is especially problematic for Nevada County with our already unhealthy ozone levels.


  • Diesel exhaust is a mixture containing over 450 different components, including vapors and fine particles coated with organic substances. The State of California considers over 40 chemicals in diesel exhaust as toxic air contaminants (see Table 1). Exposure to this mixture may result in cancer, respiratory effects and other health problems.
  • California’s Scientific Review Panel has unanimously endorsed the official listing of diesel exhaust as a toxic air contaminant, due to its cancer and non-cancer health effects.
  • Diesel exhaust has been listed as a known carcinogen under California’s Safe Drinking Water and Toxic Enforcement Act (Prop. 65) since 1990. Many components of diesel exhaust, such as benzene, arsenic, dioxins, and formaldehyde, are also known carcinogens in California. Other components, such as toluene and dioxins, are known reproductive toxicants.
  • Diesel exhaust from heavy-duty diesel engines contains between 100 to 200 times more small particles than gasoline engine exhaust. As a result, diesel engines account for an estimated 26% of the total hazardous particulate pollution from fuel combustion sources in our air, and 66% of the particulate pollution from on-road sources.
  • Diesel engines also produce nearly 20% of the total nitrogen oxides (NOx) in outdoor air and 26% of the total NOx from on-road sources. Nitrogen oxides are a major contributor to ozone production and smog.
  • The health risk from diesel exposure is greater for children, the elderly, people who have respiratory problems or who smoke, people who regularly strenuously exercise in diesel-polluted areas, and people who work or live near diesel exhaust sources.
  • EPA suggests that a cancer risk may be "negligible" if a substance induces one excess cancer out of a million people exposed over a lifetime - 1 in a million risk. According to estimates, lifetime exposure to diesel exhaust at the outdoor average concentration (2.2 micrograms per cubic meter (ug/m3) may result in more than 350 people per million developing cancer due to this exposure. This estimate increases to even higher risks for those living near freeways, distribution centers and other diesel "hot spots".
  • Dozens of studies link airborne fine particle concentrations to increased hospital admissions for respiratory diseases, chronic obstructive lung disease, pneumonia, heart disease and death. Recent evidence indicates that diesel exhaust exposure may contribute to asthma.
  • Every summer, Western Nevada County experiences episodes when concentrations of the ambient air pollutant, ground level ozone, exceed health-based standards. In 2004, Western Nevada County was designated Federal non-attainment for the air pollutant, ground level ozone. (2)
  • In California, there are 6 million children under the age of 14, 90% of whom live in areas that fail to meet federal standards for certain air pollutants. According to the American Lung Association, there are over a half million children with asthma in California.
  • Asthma is on the rise. In the United States, age-specific death rates from the disease increased 118% between 1980 and 1993.
  • Cleaner alternative to diesel engines are readily available. Alternatives include electric, liquefied natural gas (LNG) or compressed natural gas (CNG) buses and trucks.Concentrating diesel "hot spots" like distribution centers and warehouses, as well as truck terminals and truck stops greatly increases the exposures to these deadly and dangerous emissions.

Table 1: Substances in Diesel Exhaust Listed by Cal EPA as Toxic Air Contaminants

acetaldehyde inorganic lead
acrolem manganese compounds
aniline mercury compounds
antimony compounds methanol
arsenic methyl ethyl ketone
benzene naphthalene
beryllium compounds nickel
biphenyl 4-nitrobiphenyl
bis{2-ethylhexyl]phthalate phenol
1,3-butakiene phosphorus
cadmium polycyclic organic matter, including
chlorine polycyclic aromatic hydrocarbons (PAHs)
chlorobenzene propionaldehyde
chromium compounds selenium compounds
cobalt compounds styrene
creosol isomers toluene
cyanide compounds xylene isomers and mixtures
dibutylphthalate o-xylenes
dioxins and dibenzofurans m-xylenes
ethyl benzene p-xylenes


Note: California health and safety code section 39655 defines a "toxic air contaminant" as "an air pollutant which may cause or contribute to an increase in mortality or in serious illness, or which may pose a present or potential hazard to human health."

(1)Center for Community Action and Environmental Justice (CCAEJ) Dangers of Diesel

(2)Nevada County Government web siteNevada County Air Quality

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