is the only alternative fuel to voluntarily perform EPA Tier I
and Tier II testing to quantify emission characteristics and health
effects. The ozone forming potential of the hydrocarbon emissions
of pure biodiesel is nearly 50% less than that of petroleum fuel.
Pure biodiesel does not contain sulfur and therefore reduces sulfur
dioxide exhaust from diesel engines to virtually zero. Biodiesel
can also help to meet national goals for the net reduction of
is the first and only alternative fuel to have a complete evaluation
of emission results and potential health effects submitted to
the U.S. Environmental Protection Agency (EPA) under the Clean
Air Act Section 211(b). These programs include the most stringent
emissions testing protocols ever required by EPA for certification
of fuels or fuel additives. The data gathered complete the most
thorough inventory of the environmental and human health effects
attributes that current technology will allow. A survey of the
results, averaged with other major studies, is provided in the
overall ozone (smog) forming potential of biodiesel is less than
diesel fuel . The ozone forming potential of the speciated hydrocarbon
emissions was nearly 50 percent less than that measured for diesel
emissions are essentially eliminated with pure biodiesel . The
exhaust emissions of sulfur oxides and sulfates (major components
of acid rain) from biodiesel were essentially eliminated compared
to sulfur oxides and sulfates from diesel.
pollutants are reduced with biodiesel use . Tests show the use
of biodiesel in diesel engines results in substantial reductions
of unburned hydrocarbons, carbon monoxide, and particulate matter.
Emissions of nitrogen oxides stay the same or are slightly increased.
Carbon Monoxide -- The exhaust emissions of carbon monoxide (a
poisonous gas) from biodiesel are on average 47 percent lower
than carbon monoxide emissions from diesel.
Matter -- Breathing particulate has been shown to be a human health
hazard. The exhaust emissions of particulate matter from biodiesel
are about 47 percent lower than overall particulate matter emissions
-- The exhaust emissions of total hydrocarbons (a contributing
factor in the localized formation of smog and ozone) are on average
67 percent lower for biodiesel than diesel fuel.
Oxides -- NOx emissions from biodiesel increase or decrease depending
on the engine family and testing procedures. NOx emissions (a
contributing factor in the localized formation of smog and ozone)
from pure (100%) biodiesel increase on average by 10 percent.
However, biodiesel's lack of sulfur allows the use of NOx control
technologies that cannot be used with conventional diesel. So,
biodiesel NOx emissions can be effectively managed and efficiently
eliminated as a concern of the fuel's use.
reduces the health risks associated with petroleum diesel. Biodiesel
emissions show decreased levels of PAH and nitrited PAH compounds
which have been identified as potential cancer causing compounds.
In the recent testing, PAH compounds were reduced by 75 to 85
percent, with the exception of benzo(a)anthracene, which was reduced
by roughly 50 percent. Targeted nPAH compounds were also reduced
dramatically with biodiesel fuel, with 2-nitrofluorene and 1-nitropyrene
reduced by 90 percent, and the rest of the nPAH compounds reduced
to only trace levels.
Source : National Biodiesel Board, USA