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Appendix L <br /> Diesel Engine Emission Control Technologies <br /> Note: This document taken verbatim from Appendix B of the California <br /> Environmental Protection Agency Air Resources Board Staff Report: Initial <br /> Statement Of Reasons: Proposed Regulation For The Verification Procedure For <br /> In-Use Strategies To Control Emissions From Diesel Engines. Date of Release: <br /> March 29, 2002. Available at <br /> http://www.arb.ca.gov/regact/diesehv/dieselrv.htm. <br /> A variety of strategies exist for controlling emissions from diesel engines. In <br /> developing the Procedure, staff has striven to acknowledge the range of control <br /> strategies,and intends for the Procedure to be flexible enough to accommodate <br /> all such strategies. The following discussion briefly reviews the more prominent <br /> diesel emission control strategies thus far identified and,where appropriate, <br /> indicates how the Procedure addresses them. <br /> Diesel Oxidation Catalyst <br /> A diesel oxidation catalyst(DOC)converts pollutants into harmless gases by <br /> means of oxidation. In addition to oxidizing compounds such as carbon <br /> monoxide(CO)and gaseous hydrocarbons(HC), oxidation catalysts can reduce <br /> the mass of the liquid-phase HCs(unburned fuel and oil)by 90 percent under <br /> certain operating conditions. The liquid HCs,or soluble organic fraction(SOF), <br /> contribute up to 30 percent of the total particulate matter(PM)mass. <br /> There are some potential adverse environmental impacts of DOCS. First, as is <br /> the case with most processes that incorporate catalytic oxidation,the formation of <br /> sulfates increases at higher temperatures. Depending on the exhaust temperature <br /> and sulfur content of the fuel, the increase in sulfate particles may offset the <br /> reductions in SOF emissions. Using low sulfur(15 parts per million)diesel fuel <br /> can minimize this effect. <br /> Additionally,DOCS and other strategies that involve catalytic action(e.g., <br /> passive diesel particulate filters—see below)can increase the proportion of NO2 <br /> ` relative to NO,even though total NOx emissions do not increase. As described <br /> in the body of the report,there are concerns with an increase in NO2,and the <br /> proposal includes a limit on NO2 emissions. <br /> r <br /> �+ DeSilva Gates Quarry Project <br /> Draft Environmental Impact Report L-t <br /> As 05105.05 <br /> f! <br />