Emission Factors

To determine an engine’s emissions, an owner/operator may use:

  1. Default SBCAPCD Diesel Engine Emission Factors – For use with older engines (see the first table presented below), or
  2. USEPA emission standards for Tier 1 – 4 engines (see the second table presented below)
Default SBCAPCD Diesel Engine Emission Factors
Pollutant Emission Factor Units Ref
PM 1.0 g/bhp-hr 1
NOx (as NO2) 14.1 g/bhp-hr 1
NMHC 1.12 g/bhp-hr 1
NMHC+NOx 15.22 g/bhp-hr 1
CO 3.0 g/bhp-hr 1
SOx (as SO2) 3.67 * wt %S g/bhp-hr 2

basis: (1) USEPA AP-42, Table 3.3-1, (2) USEPA AP-42, Table 3.3-2, where S = wt  % of sulfur (eg, for S = 0.05 wt %: SOx = (3.67)*(0.05) = 0.183 g/bhp-hr.  Assume NMHC = ROC

USEPA Emission Standards for Tier 1 – 4 engines
 Engine Power (hp) Model Years  Regulation  Emission Standards (g/hp-hr) Year the Std Takes Effect
 HC a, c VHC b  NOx a, c  NMHC+NOx a  CO a  PM a
 50 to <75  1998-2003  Tier 1 6.90 1998
 2004-2007  Tier 2 0.40 0.3996 5.20 5.60 3.70 0.30 2004
 2008-2012  Tier 3 0.20 0.1998 3.3 3.50 3.70 0.30 2008
 2013 +  Tier 4 0.20 0.1998 3.3 3.50 3.70 0.02 2013
>75 to <100  1998-2003  Tier 1 6.90 1997
 2004-2007  Tier 2 0.40 0.3996 5.20 5.60 3.70 0.30 2004
 2008-2011  Tier 3 0.20 0.1998 3.3 3.50 3.70 0.30 2008
 2012-2013  Tier 4 transitional 0.14 0.1399 0.30 3.70 0.01 2012
 2014 +  Tier 4 0.14 0.1399 0.30 3.70 0.01 2014
>100 to <175  1997-2002  Tier 1 6.90 1997
 2003-2006  Tier 2 0.40 0.3996 4.5 4.90 3.70 0.22 2003
 2007-2011  Tier 3 0.20 0.1998 2.8 3.00 3.70 0.22 2007
 2012-2013  Tier 4 transitional 0.14 0.1399 0.30 3.70 0.01 2012
 2014 +  Tier 4 0.14 0.1399 0.30 3.70 0.01 2014
>175 to <300  1996-2002  Tier 1 1.00 0.9990 6.90 8.50 0.40 1996
 2003-2005  Tier 2 0.40 0.3996 4.5 4.90 2.60 0.15 2003
 2006-2010  Tier 3 0.20 0.1998 2.8 3.00 2.60 0.15 2006
 2011-2013  Tier 4 transitional 0.14 0.1399 0.30 2.60 0.01 2011
 2014 +  Tier 4 0.14 0.1399 0.30 2.60 0.01 2014
>300 to <600  1996-2000  Tier 1 1.00 0.9990 6.90 8.50 0.40 1996
 2001-2005  Tier 2 0.30 0.2997 4.5 4.80 2.60 0.15 2001
 2006-2010  Tier 3 0.20 0.1998 2.8 3.00 2.60 0.15 2006
 2011-2013  Tier 4 transitional 0.14 0.1399 0.30 2.60 0.01 2011
 2014 +  Tier 4 0.14 0.1399 0.30 2.60 0.01 2014
>600 to <750  1996-2001  Tier 1 1.00 0.9990 6.90 8.50 0.40 1996
 2002-2005  Tier 2 0.30 0.2997 4.5 4.80 2.60 0.15 2002
 2006-2010  Tier 3 0.20 0.1998 2.8 3.00 2.60 0.15 2006
 2011-2013  Tier 4 transitional 0.14 0.1399 0.30 2.60 0.01 2011
 2014 +  Tier 4 0.14 0.1399 0.30 2.60 0.01 2014
 >750 except generator sets  2000-2005  Tier 1 1.00 0.9990 6.90 8.50 0.40 2000
 2006-2010  Tier 2 0.30 0.2997 4.5 4.80 2.60 0.15 2006
 2011-2014  Tier 4 transitional 0.30 0.2997 2.60 2.60 0.08 2011
 2015 +  Tier 4 0.14 0.1399 2.60 2.60 0.03 2015
 Generator sets >750 to <1200  2000-2005  Tier 1 1.00 0.9990 6.90 8.50 0.40 2000
 2006-2010  Tier 2 0.30 0.2997 4.5 4.80 2.60 0.15 2006
 2011-2014  Tier 4 transitional 0.30 0.2997 2.60 2.60 0.08 2011
 2015 +  Tier 4 0.14 0.1399 0.50 2.60 0.02 2015
 Generator sets >1200  2000-2005  Tier 1 1.00 0.9990 6.90 8.50 0.40 2000
 2006-2010  Tier 2 0.30 0.2997 4.5 4.80 2.60 0.15 2006
 2011-2014  Tier 4 transitional 0.30 0.2997 0.50 2.60 0.08 2011
 2015 +  Tier 4 0.14 0.1399 0.50 2.60 0.02 2015
Notes:

a Nonroad CI Engine Emission Standards from Title 13, California Code of Regulations, Section 2423 (ARB Executive Order “Std”).

b VHC = Total Hydrocarbons (THC) minus methane and ethane fractions.  Equivalent APCD standard. (Highlighted in Orange)  See Conversion Factors to Hydrocarbon Emission Components, Report No. NR-002a, US EPA, 5/2003.  {VHC = ROC}

c Tier 2 and Tier 3 HC and NOx equivalent standards used to determine the NMHC + NOx standard.  (Highlighted in blue)

For more information or assistance, call or email Mike Goldman at (805) 961-8821.

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