From: Melanie King/RTP/USEPA/US 

To: "Higgins 

cc: Peter Tsirigotis/RTP/USEPA/US@EPA, RobertJ Wayland/RTP/USEPA/US@EPA 

Date: Wednesday, February 17, 2010 02:39PM 

Subject: Re: RICE -- edits 

Hi Cortney, 

We reviewed the suggested edits to the RIA. Attached are the edits that we are comfortable 

making. We do not feel comfortable making any changes beyond these. I am also adding this 

statement to the impacts memo: " For estimating the number engines located at major 

and area 

sources, we used our best engineering judgment, and we recognize that it 

may lead to an overestimate or underestimate of costs and benefits for 

certain sectors. " 

(See attached file: RIA edits.pdf)

Thanks, 

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 

 "Higgins, Cortney" ---02/17/2010 01:00:17 PM---Hi Melanie, I've attached a pdf of suggested 

changes to the RIA -- the first is to

Hi Melanie, 

I've attached a pdf of suggested changes to the RIA -- the first is to 

try to address concerns about ground level transport and the 

characertization, the second clarifies some of the hazardous constituent 

language. Please let me know if you have concerns about either of these 

or if you can work them into the RIA. 

From: "Higgins, Cortney" <Cortney_Higgins@omb.eop.gov>

To: Melanie King/RTP/USEPA/US@EPA

Cc: RobertJ Wayland/RTP/USEPA/US@EPA, Peter Tsirigotis/RTP/USEPA/US@EPA

Date: 02/17/2010 01:00 PM

Subject: RICE -- edits

Page 1 of 2

https://rtairmail1.rtp.epa.gov/mail/mking.nsf/($Sent)/98707E4F63EC643F852576CD006B... 2/17/2010
Additionally, could you also consider the following: USDA still 

questions the assumption about the distribution of irrigation engines 

among major and area sources. Given the signature deadline, can you add 

some language to the source estimates memo, and possibly to the RIA, 

that states "For estimating the number engines located at major and area 

sources, we used our best engineering judgment, and we recognize that it 

may lead to an overestimate or underestimate of costs and benefits for 

certain sectors." Another suggestion is the following: " Given that few 

farms are known to be current major sources, less than 40% of the farms 

with RICE engines may be located at major sources, but EPA did not have 

available data to quantify an alternative estimate." 

Finally, is the limited use category for area sources supposed to be for 

engines greater than 500 or 300? The regulatory language and preamble 

uses a 500 threshold, but retrofits are required for area source engines 

greater than 300, and, the costs of retrofits for 300 HP engines running 

less than 100 hours a year does not exceed the low end of the benefits 

range. 

Please give me a call if you have questions. 

Regards, 

Cortney 

[attachment "CI RICE NESHAP RIA 2-17-10_p133.pdf" deleted by Melanie 

King/RTP/USEPA/US] [attachment "CI RICE NESHAP RIA 2-17-10_p119.pdf" deleted by 

Melanie King/RTP/USEPA/US] 

Attachments:

RIA edits.pdf

Page 2 of 2

https://rtairmail1.rtp.epa.gov/mail/mking.nsf/($Sent)/98707E4F63EC643F852576CD006B... 2/17/2010
The underlying emissions modeling and air quality modeling account for the current distribution 

of emissions sources, including both urban and rural sources. In addition, the air quality modeling 

included 14 vertical layers to simulate the differences between ground-level emissions and higher stack 

emissions (U.S. EPA, 2006a). The distance that particles travel primarily depends on the size of the 

particle, the amount and release height of emissions, terrain, and meteorological conditions, such as wind 

speed and precipitation. Fine particles can have an atmospheric half-life of days to weeks and travel 

hundreds to thousands of kilometers, whereas ultrafine and coarse particles travel less than ten kilometers 

(U.S. EPA, 2009c). Because we have not undertaken a study specific to emissions at ground level from 

RICE, with regard to transport issues and to size fraction of PM2.5 emissions (e.g., ultrafines and near 

ultrafines), there is uncertainty as to how far such emissions will travel and thus with regard to 

populations affected. Evidence from recent air quality modeling for mobile source rules with similar 

engines (U.S. EPA, 1999; U.S. EPA, 2000; U.S. EPA, 2004; U.S. EPA, 2008e; U.S. EPA, 2010c) shows 

that some fine particles can travel long distances in the atmosphere, but the proportion of such emissions 

from RICE that travel more than short distances under typical ground level meteorological conditions is 

not yet definitively definitively known, thus introducing a potentially important source of uncertainty.

The distance that these HAPs travel away from the emission source depends on several factors. 

HAPs such as formaldehyde, acetaldehyde, PAHs, and acrolein are emitted as gases. Regional 

photochemical model simulations, examining particular scenarios, have shown that gaseous HAPs like 

formaldehyde and acetaldehyde can be transported hundreds of kilometers from their emissions source in 

distinct plumes (U.S. EPA, 2010b). Further, these emissions can contribute to regional airmasses with 

elevated concentrations of gaseous HAPs. These polluted airmasses, under the scenarios examined, can 

be transported thousands of kilometers and affect locations well distant from the original emissions 

source. Some gaseous HAPs with higher molecular weight, such as toluene, can transform into particles 

in the atmosphere. For engines examined in this rule, EPA does not have enough information to 

determine how far each of the HAPs will travel the extent of transport specific to these HAPs. For In 

general, for HAPs emitted as particles, such as metals, the travel distance primarily depends on the size of 

the particle and meteorological conditions, such as wind speed and precipitation. Fine particles can have 

an atmospheric half-life of days to weeks and travel hundreds to thousands of kilometers, whereas 

ultrafine and coarse particles travel less than ten kilometers (U.S. EPA, 2009c). The level at which the 

emissions occur can also play a role in determining transport distances. For instance, ground level 

emissions are less likely to travel long distances when compared to particles emitted substantially above 

ground level.