<html><head><style type="text/css"><!-- DIV {margin:0px;} --></style></head><body><div style="font-family:arial,helvetica,sans-serif;font-size:10pt">Dennis,<br><br>I would have to dust off my old atmospheric chemistry textbooks, but I would guess that the atmospheric lifetime of propane is pretty short relative to long-lived GHGs, such as those covered under the Kyoto Protocol. Typically for GWPs we focus on the direct radiative forcing effect, which is of the propane molecule itself. I think it is safe to assume that propane has a short atmospheric life-time, as I do not hear anyone talking about propane accumulating in the atmophere. I checked at old reference, and even in dirty LA air, the mixing ratio of propane is only about 18 ppb. <br><br>Even if propane had a powerful instantaneous radiative forcing effect (with is probably doesn't), it is not around long enough to do much.<br><br>Now, propane could have some indirect radiative
forcing effects, such as its impact on ozone formation, as a sink for OH (which would cause methane to say around longer), and by oxidation to CO2, as noted by Mark below. However, the GWPs we use for GHG accounting under most conventions, almost exclusively rely on direct GWP values.<br><br>michael <br><div> </div><span style="font-family: verdana,helvetica,sans-serif;"></span><font style="font-family: verdana,helvetica,sans-serif;" size="2"><br></font><hr style="width: 100%; height: 2px; font-family: verdana,helvetica,sans-serif;"><font style="font-family: verdana,helvetica,sans-serif; color: rgb(127, 127, 0);" size="2"><a rel="nofollow" target="_blank" href="http://www.princeton.edu/%7Emgillenw/biography.htm">Michael Gillenwater</a><br><a rel="nofollow" target="_blank" href="http://www.princeton.edu">Princeton University</a><br><a rel="nofollow" target="_blank" href="http://www.princeton.edu/%7Estep/">Science, Technology and
Environmental Policy Program</a><br><br><a rel="nofollow" target="_blank" href="http://www.ghginstitute.org">GHG Management Institute</a> (Dean of Institute)*<br></font><font style="font-family: verdana,helvetica,sans-serif; color: rgb(127, 127, 0);" size="2"><a rel="nofollow" target="_blank" href="http://www.ghgnetwork.org">GHG Experts Network</a> <span style="text-decoration: underline;"></span> (Executive Director)*</font><font style="font-family: verdana,helvetica,sans-serif; color: rgb(127, 127, 0);" size="2"><br></font><span style="font-family: verdana,helvetica,sans-serif; color: rgb(127, 127, 0);"></span><hr style="width: 100%; height: 2px; font-family: verdana,helvetica,sans-serif; color: rgb(127, 127, 0);"><span style="font-family: verdana,helvetica,sans-serif; color: rgb(127, 127, 0);"></span><font style="font-family: verdana,helvetica,sans-serif; color: rgb(127, 127, 0);" size="1">* Organizations are independent non-profits and are not
associated with Princeton University.</font><br style="font-family: verdana,helvetica,sans-serif;"><div><br></div><div style="font-family: arial,helvetica,sans-serif; font-size: 10pt;"><br><div style="font-family: times new roman,new york,times,serif; font-size: 12pt;">----- Original Message ----<br>From: Mark A. Delucchi <madelucchi@ucdavis.edu><br>To: Dennis O'Regan <doregan@libertyenviro.com><br>Cc: discuss@ghgnetwork.org<br>Sent: Wednesday, July 16, 2008 7:57:44 PM<br>Subject: Re: [GHG Network] Propane and GWPs<br><br>
Dennis, <div><br></div><div>Offhand, I don't know of any estimates of the radiative forcing of propane, but they might be out there. I suspect that the so-called "indirect" effects of propane -- which should be analogous to the indirect effects of CH4 -- will be larger than any direct radiative forcing effects. <div><br></div><div>In my lifecycle emissions model I estimate some of the indirect climate effects of propane emissions: the effect on O3, the effect on CH4, and the effect on SO4. The effect on O3 is estimated on the basis of the ozone-forming potential of propane. I also include, of course, the effect of the final oxidation to CO2. All of my estimates are very simple.<br><div><br></div><div>Best, </div><div><br></div><div><div><div><div><span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal;
letter-spacing: normal; line-height: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px;"><span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; text-indent: 0px; text-transform: none; orphans: 2; white-space: normal; widows: 2; word-spacing: 0px;"><div>Mark Delucchi</div><div>Research Scientist</div><div>Institute of Transportation Studies</div><div>University of California</div><div>Davis, CA 95616</div><div><br class="khtml-block-placeholder"></div><div>www.its.ucdavis.edu/people/faculty/delucchi</div><div><a rel="nofollow" ymailto="mailto:madelucchi@ucdavis.edu" target="_blank" href="mailto:madelucchi@ucdavis.edu">madelucchi@ucdavis.edu</a></div><div><br class="khtml-block-placeholder"></div><br
class="Apple-interchange-newline"></span></span><br class="Apple-interchange-newline"></div><br><div><div>On Jul 16, 2008, at 3:52 PM, Dennis O'Regan wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div style="margin: 0px; min-height: 14px;"><br></div><div style="margin: 0px;">I am doing some research that involves GHGs due to propane production and use.<span class="Apple-converted-space"> </span>I have been trying to find information on the possible radiative forcing of propane emissions, not unlike the radiative forcing of CH4, but so far I have not found any information. I know that propane is not one of the six IPCC families of gases and its oxidation simply yields CO2.<span class="Apple-converted-space"> </span>But the IPCC being silent on it does not answer the question.</div><div style="margin: 0px; min-height: 14px;"><br></div><div style="margin: 0px;">A couple of questions: (1) has there been any research
on establishing a GWP for propane?; (2) since propane is widely used (at least in the USA), fugitive emissions would seem to be a logical concern and, in turn, what happens to these emissions in the atmosphere?<span class="Apple-converted-space"> </span>Any leads or insights would be appreciated.</div><div style="margin: 0px;">Regards,</div><div style="margin: 0px;">Dennis</div><div style="margin: 0px;">_______________________________________________</div><div style="margin: 0px;">Greenhouse Gas Inventory Experts Network</div><div style="margin: 0px;">www.ghgnetwork.org</div><div style="margin: 0px; min-height: 14px;"><br></div><div style="margin: 0px;">To post message:</div><div style="margin: 0px;">Discuss mailing list</div><div style="margin: 0px;"><a rel="nofollow" ymailto="mailto:Discuss@ghgnetwork.org" target="_blank" href="mailto:Discuss@ghgnetwork.org">Discuss@ghgnetwork.org</a></div><div style="margin: 0px; min-height:
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