From: Paul Miller <pmiller@nescaum.org> 
To: Melanie King/RTP/USEPA/US@EPA 
Date: 10/11/2012 12:05 PM 
Subject: RE: NESCAUM's RICE NESHAP comments
 
 
 
 
Hi Melanie, 
The NESCAUM fuel oil sampling study is out and posted on NESCAUM’s website at 
http://www.nescaum.org/documents/nyserda-determination_sulfur_toxic_metals-201012-final.pdf/. 
 
For an ultralow sulfur diesel (ULSD) tie to HAPs, there are two ways of looking at the use of ULSD that you’re 
probably well aware of. 
 
First, in our comments we also recommended requiring diesel particulate filters (DPFs) where RICE are receiving 
economic payments to participate in demand response programs (and our estimates of control costs vs. revenues 
the owners can receive indicated the payback for controls was 5 years or less). DPFs require ultralow sulfur diesel 
to operate correctly. Because diesel exhaust contains a number of HAPs, use of ultralow sulfur diesel in order for 
DPFs to function will reduce HAPs by reducing total diesel exhaust emissions, both in terms of hydrocarbon mass as 
well as in particulates. Reductions in hydrocarbon mass mean large reductions in HAPs like BTEX and polycyclic 
organic matter (or PAHs). For particulates, I think one can use the same approach as in EPA’s Utility MATS rule, 
which uses particulate matter as a surrogate for HAP metals (i.e., reductions in PM mean reductions in HAP metals). 
Overall, I think EPA’s previous rulemakings on ultralow sulfur diesel use with on-road and off-road diesel engines 
would provide supporting information on this, and EPA’s 2002 Health Assessment for Diesel Exhaust provides info 
on the stew of air toxics in diesel exhaust that a combination of ultralow sulfur diesel and DPFs can significantly 
reduce (http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=29060).  
 
Second, while available info is not as extensive as with the combination of ultralow sulfur diesel and DPFs, there is 
evidence in the peer-reviewed literature that the use of ultralow sulfur diesel alone without aftertreatment 
controls can also reduce air toxics, such as the BTEX compounds and metals. The studies I have are focused on 
heavy-duty vehicles, but it seems applicable to stationary diesel engines as well. My sampling of the literature 
includes the following:
1. Tang et al., Unregulated Emissions from a Heavy-Duty Diesel Engine with Various Fuels and Emission 
Control Systems, EST (2007) (electronic preprint attached). Table 3 of this study indicates that ultralow 
sulfur diesel (E-ULSD) without aftertreatment controls (“Engine-Out” test) has lower BTEX emissions 
compared to the more conventional higher sulfur diesel fuels (D1, D2, and LSD). It isn’t clear why lowering 
sulfur has this impact, but it’s seen in other studies (below). 
2. Lowell, et al., Comparison of Clean Diesel Buses to CNG Buses, MTA New York City Transit, 2003 
(attached). This study isn’t in the peer-reviewed literature (although there may be an SAE article based on 
these results that I couldn’t find on-line). This paper shows results in Figures 4 and 11 that are consistent 
with the Tang et al. results above. Figure 4 indicates a large reduction in total hydrocarbon emissions from 
an uncontrolled diesel engine when going from conventional diesel to ultralow sulfur diesel, and Figure 11 
shows similar large reductions in benzene. PAHs don’t look good for ULSD in this study (but see below). 
Even so, keep in mind total hydrocarbons are significantly reduced, which would bring down other air 
toxics in the exhaust. Also note that the ULSD with a DPF shows additional reductions across all air toxics. 
3. Lim et al., Effect of fuel composition and engine operating conditions on polycyclic aromatic 
hydrocarbon emissions from a fleet of heavy-duty diesel buses, Atmos. Envt., Vol. 40, pp. 7836–7848 
(2005), doi: 10.1016/j.atmosenv.2005.09.019. Somewhat different findings with respect to PAHs than in 
the Lowell et al. study above – use of ULSD (50 ppm) in heavy-duty diesel buses without aftertreatment 
controls resulted in significant reduction in PAH emissions and toxicity of the exhaust, compared to LSD 
(500 ppm). 
4. Lim et al., The effects of fuel characteristics and engine operating conditions on the elemental 
composition of emissions from heavy duty diesel buses, Fuel, Vol. 86, pp. 1831–1839 (2007), doi: 
10.1016/j.fuel.2006.11.025. Table 3 of this study indicates tailpipe emissions of the metals Ti, Mg, Ca, Cr, 
Fe, Cu, Zn and Pb are lower when using ULSD (50 ppm) compared to LSD (500 ppm) in heavy-duty buses 
without aftertreatment controls. 
 
I don’t have reprints of articles 3 & 4 above, but assume you can get these in EPA’s library. 
 
In sum, ULSD with DPFs would have the greatest benefit in reducing air toxics, and we think it’s very cost effective 
when considering the revenues the RICE owners are getting from demand response programs. Even without DPFs, 
while the literature is more sparse, there are several consistent findings that ULSD alone lowers air toxics from 
diesel engines.  
 
I hope this helps, and let me know if you have further questions. I appreciate the opportunity to provide additional 
supporting information. –Paul 
 
 
Paul J. Miller, Deputy Director 
Northeast States for Coordinated Air Use Management 
89 South Street, Suite 602, Boston, Massachusetts, 02111 | 617.259.2016 | Fax: 617.742.9162 | 
www.nescaum.org 
 
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From: Melanie King [mailto:King.Melanie@epamail.epa.gov]  
Sent: Wednesday, October 10, 2012 2:21 PM 
To: Paul Miller 
Subject: NESCAUM's RICE NESHAP comments
Hi, 
I'm following up on the comments submitted by NESCAUM on the proposed amendments to the RICE 
NESHAP (see attached). One of the recommendations in the comments was for EPA to require the use 
of ultra low sulfur diesel fuel for engines participating in demand response programs. Given that the rule 
is focused on reducing hazardous air pollutant (HAP) emissions, one of the barriers we face in adopting 
that recommendation is a lack of data that shows switching to ULSD results in a reduction in HAP 
emissions from the engines. I'm writing to ask if you have any information to show that there would be a 
reduction in HAP emissions from a switch to ULSD? I saw at the link below that NESCAUM was 
performing a study to determine the trace metals in different distillate fuels. Are the results from this 
study available? http://www.nescaum.org/activities/projects-in-progress/fuel-oil-testing-for-trace-metals-
and-sulfur-content 
 
(See attached file: EPA-HQ-OAR-2008-0708-1033 NESCAUM.pdf) 
 
Melanie King 
Energy Strategies Group 
Sector Policies and Programs Division 
Office of Air Quality Planning and Standards 
U.S. Environmental Protection Agency 
Mail Code D243-01 
RTP, NC 27711 
Phone: (919) 541-2469 
Fax: (919) 541-5450 
king.melanie@epa.gov(See attached file: Tang-HDD emissions with various fuels and 
controls_EST2007.pdf)(See attached file: Lowell-NYC MTA 2003 Diesel v CNG 829622.pdf)
