Crimson Biodiesel    Production
What is Biodiesel?
Benefits of Biodiesel
Who Uses Biodiesel?
Usage Guidelines
Biodiesel vs. Diesel
   - Specifications &      Performance
Biodiesel Emissions
Biodiesel Myths versus    Facts
White Paper: Cold    Flow Properties of    Blends of Tallow and    Soybean Oil-based    Biodiesel

BIODIESEL EMISSIONS OVERVIEW - The Impact on California Air Quality -
There is a growing body of emission data for biodiesel. Compared to conventional diesel, the use of B100 significantly reduces particulate emissions (PM), carbon/ carbon monoxide (CO and CO2), and hydrocarbons (HC). With respect to nitrogen oxide (NOx) emissions, studies have shown small variations compared to conventional petroleum-based diesel. In comparing B20 to conventional diesel fuel, the changes in emissions are directionally the same, but smaller.

The California Air Resources Board (CARB) reports that B100 and B20 reduce PM emissions by 30% and 22%, respectively when compared to conventional diesel fuel.1 The National Biodiesel Board (NBB) conducted research and testing that demonstrated PM reductions of 40% for B100 and 8% for B202. In its 2002 draft report on biodiesel emissions, the EPA reported an average PM reduction of 10.1% for soybean based B20 fuel, and a 2% increase in NOx emissions3. The EPA also reported that emissions varied with the type of biodiesel used (soybean, rapeseed, animal fats), and that emissions benefits appeared consistent across engine model years.

In a recently completed study on life-cycle emissions from biodiesel and petroleum diesel, the U.S. Department of Energy (DOE) concluded that tailpipe PM10 emissions are 68% lower for biodiesel, while biodiesel life-cycle particulate emission are 32% lower than conventional diesel fuel4. A summary of biodiesel emissions and their impact in California is presented below:

Table 1: Biodiesel Emissions Compared to Diesel Fuel

	B100	B20	B5	B2
CO	-45%	-11%	-3.2%	-1.3%
CO2	-48%	-12%	-3.9%	-1.5%
PM	-47%	-12%	-3.1%	-1.2%
NOx	+10%	-2% to +2%	-1% to 1%	0% / negligible
PAH (polycyclic aromatic hydrocarbons)	-80%	-13%	not reported	not reported
nPAH (nitrated PAHs)	-90%	-50%	not reported	not reported
Ozone Potential of Speciated Hydrocarbons	-50%	-10%	not reported	not reported

Annual California Mobile Source Emission Impacts of B2 and B5 Biodiesel Blends*

	CO tons/yr	CO2 tons/yr	PM tons/yr
B2 (with #2 CARB Diesel)	-1,934 tpy	-427,040 tpy	-269.5 tpy
B5 (with #2 CARB Diesel)	-4,805 tpy	-1.06 million tpy	-666.3

In 2003 the Washington Metropolitan Area Transit Authority investigated bus emissions resulting from the use of conventional diesel fuel, ultra-low sulfur diesel fuel (ULSD) and a blend of 20 percent biodiesel and 80 percent ULSD (B20)5. During the ULSD and B20 tests the transit bus was equipped with a catalyzed particulate trap. The B20 fuel showed virtually similar PM reduction efficiencies compared to ULSD fuel and reduced PM emissions by greater than 98% as compared to the baseline diesel fuel. While showing a slight increase in NOx emissions, the B20 blend also reduced both CO and HC emissions by 90% over the ULSD fuel.

In terms of the health care costs of pollution related to diesel fuel, research in California shows that the use of conventional diesel fuel is the state’s largest source of particulate matter (PM) emissions. These diesel fuel related PM emissions are responsible for an estimated 3,000 premature deaths, 70% of the state’s cancer risk, 2,700 cases of bronchitis, and 4,400 hospital admissions, ultimately creating additional health care costs totaling $21.5 billion6.

The maps depicted below show the estimated cancer risk for getting cancer in the Los Angeles metropolitan area over a 70-year lifetime, and are based on replotting the South Coast Air Quality Management District MATES-II data. The SCAQMD maps showed cancer color-coded up to 1200 cases per million, although the SCAQMD’s estimated data values went as high as 5800. These maps present an updated view of the cancer risk based on all current emissions as well as an alternate scenario where diesel fuels are not burned at all.

Given the importance of diesel engines and fuel to the California economy, a “no diesel fuel” scenario is completely unrealistic. However, the use of biodiesel fuels can substantially reduce the volume of harmful emissions and pollutants emanating from diesel engines, and decrease the related health risks and healthcare costs.