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<p class="MsoNormal">Hi Qi, <o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">It is possible to achieve a photon flux of about 6e15 photons/cm2/s with all four lamps turned on at maximum intensity. For more details, see Section 2.2.1 and Fig. S4 of this paper:
<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal" style="text-align:justify;background:white"><span style="font-size:10.0pt;font-family:"Arial",sans-serif;color:black">Lambe, A. T., Krechmer, J. E., Peng, Z., Casar, J., Carrasquillo, A. J., Raff, J. D., Jimenez, J. L., and Worsnop, D.
R.: HO<sub>x</sub> and NO<sub>x</sub> production in oxidation flow reactors via photolysis of isopropyl nitrite, isopropyl nitrite-d<sub>7</sub>, and 1,3-propyl dinitrite at λ = 254, 350, and 369 nm, <i>Atmos. Meas. Tech</i>., 12, 299-311,
<a href="https://doi.org/10.5194/amt-12-299-2019">https://doi.org/10.5194/amt-12-299-2019</a>, 2019. <a href="https://www.atmos-meas-tech.net/12/299/2019/amt-12-299-2019.html"><span style="color:#4E7DBF">Abstract</span></a>, <a href="https://www.atmos-meas-tech.net/12/299/2019/amt-12-299-2019.pdf"><span style="color:#4E7DBF">PDF </span></a>and <a href="https://www.atmos-meas-tech.net/12/299/2019/amt-12-299-2019-supplement.pdf"><span style="color:#4E7DBF">Supplement</span></a>. </span><span style="font-size:10.0pt;font-family:"Arial",sans-serif;color:black"><o:p></o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I have heard of groups using flow rates as low as 2-3 L/min. It might be also possible to operate at lower rates, but I have not attempted this myself, and have not received feedback from others that might have tried it. If you like, you
are welcome to email <a href="mailto:aerodyne-pam-users@lists.aerodyne.com">aerodyne-pam-users@lists.aerodyne.com</a> to poll other OFR users on their experience. Or if you prefer, I can ask the question myself on your behalf. <o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Andy<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><b>From:</b> Qi Zhang <dkwzhang@ucdavis.edu> <br>
<b>Sent:</b> Wednesday, May 5, 2021 4:48 PM<br>
<b>To:</b> Andy Lambe <lambe@aerodyne.com><br>
<b>Subject:</b> RE: Question about the PAM light source<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span style="color:#1F497D">Hi Andy, <o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">Thanks much for sharing the information. I have been trying to get funds to purchase a PAM. One of the applications of PAM I am considering is to study phenol oxidation in aerosol water under simulated sunlight
illumination. The idea is to extend the works my group has done on phenol reactions in diluted aqueous solution representative of fog/cloud waters. The photoreactor we use for aqueous reactions has a set of light tubes installed along the chamber wall to generate
photons > 300 nm. To mimic sunlight spectrum, we use a combination of lamps that emit lights in different wavelength range. We see fast aqueous oxidation of phenols and by changing solution concentration, we see evidence of changing reaction rates as well
as product composition as a result of increase of solution concentration and the presence of salts. This suggests that aqueous reactions of phenols In cloud water are quite different than those in aerosol water. <o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">Using our photoreactor approach, we cannot reach highly concentrated condition relevant to ambient aerosol water. So I thought about using PAM to explore such reactions. I think by increasing humidity inside
the chamber, we may be able to expose hydrated phenol-containing particles to lights inside PAM, thus are able to examine the decay of phenols and production of SOA under aerosol water conditions. This is the reason I am interested in having lamps that produce
sunlight relevant lights. It is good to know there are indeed such lamps. Either of the three lamps you shared could work. We need to do so calculations to check is the light intensity is strong enough to allow for fast enough reaction. BTW, what’s the highest
residence time workable for PAM? I know the chamber size is 13 L, so at AMS flow rate of 0.1 L/min, we can get to 130 min max. Of cause particle loss would be a concern, but we can try to correct for that. <o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">I’d very much like to hear your thoughts on the plan mentioned above. Thanks!
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;color:#7F7F7F">Qi <o:p></o:p></span></p>
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<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b>From:</b> Andy Lambe <<a href="mailto:lambe@aerodyne.com">lambe@aerodyne.com</a>>
<br>
<b>Sent:</b> Tuesday, May 4, 2021 8:57 PM<br>
<b>To:</b> Qi Zhang <<a href="mailto:dkwzhang@ucdavis.edu">dkwzhang@ucdavis.edu</a>><br>
<b>Subject:</b> RE: Question about the PAM light source<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Hi Qi, <o:p></o:p></p>
<p class="MsoNormal">We have lights emitting in the UVB or UVA – see attached.<o:p></o:p></p>
<p class="MsoNormal">Other wavelengths are available from the manufacturer, but the above are normally stocked at Aerodyne.
<o:p></o:p></p>
<p class="MsoNormal">They won’t work as well for generating OH “the normal way” – mostly useful for photolysis of isopropyl nitrite (high-NOx OH source), or chlorine (Cl source), but maybe you are considering doing something else with them (?)
<o:p></o:p></p>
<p class="MsoNormal">Let me know more details about what you’re interested in, and I’ll try to help.
<o:p></o:p></p>
<p class="MsoNormal">Andy<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><b>From:</b> Qi Zhang <<a href="mailto:dkwzhang@ucdavis.edu">dkwzhang@ucdavis.edu</a>>
<br>
<b>Sent:</b> Tuesday, May 4, 2021 11:48 PM<br>
<b>To:</b> Andy Lambe <<a href="mailto:lambe@aerodyne.com">lambe@aerodyne.com</a>><br>
<b>Subject:</b> Question about the PAM light source<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Hi Andy, <o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I have a quick question about the light source for PAM – are there lamps used in PAM that can generate lights mimicking solar spectrum or above 290 nm? If not, are you aware of efforts to make that happen? Thanks!
<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Qi <o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span style="font-size:10.0pt;color:#7F7F7F">Qi Zhang <o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;color:#7F7F7F">===========================================
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;color:#7F7F7F">Professor <o:p>
</o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;color:#7F7F7F">4251A Meyer Hall (Office), 4422 Meyer Hall (Lab)
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;color:#7F7F7F">Department of Environmental Toxicology
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;color:#7F7F7F">University of California, Davis, CA 95616
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;color:#7F7F7F">Email: <a href="mailto:dkwzhang@ucdavis.edu">
<span style="color:#7F7F7F">dkwzhang@ucdavis.edu</span></a> <o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;color:#7F7F7F">Phone: 530-752-5779 (Office); 530-752-2541 (Lab)
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;color:#7F7F7F">Fax: 530-752-3394
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;color:#7F7F7F"><a href="https://us-east-2.protection.sophos.com?d=google.com&u=aHR0cHM6Ly9zaXRlcy5nb29nbGUuY29tL3NpdGUvcWl6aGFuZ2dyb3VwLw==&i=NWZlMzY0NmMyMDVjNjQwZTE1YzFlYTc4&t=K3pDMVkzaUd2NmFuR2lYYWppcC9IL1l4dTlTeE5vUDFacm52YjhxSTF2ND0=&h=50e01f82291547cba2b1fae15b6fcad3"><span style="color:blue">https://sites.google.com/site/qizhanggroup/</span></a>
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;color:#7F7F7F"><a href="https://us-east-2.protection.sophos.com?d=google.com&u=aHR0cHM6Ly9zaXRlcy5nb29nbGUuY29tL3NpdGUvYW1zZ2xvYmFsZGF0YWJhc2Uv&i=NWZlMzY0NmMyMDVjNjQwZTE1YzFlYTc4&t=eFlud3RrSThNaEtVTVlVcHlZRXdmVytqZitXWnF1OC9YdXZlZmtBWFFFZz0=&h=50e01f82291547cba2b1fae15b6fcad3"><span style="color:blue">https://sites.google.com/site/amsglobaldatabase/</span></a>
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;color:#7F7F7F">===========================================
<o:p></o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p><strong><span style="font-family:"Calibri",sans-serif;color:black;background:yellow">Caution:</span></strong>This message originated from outside of Aerodyne. Do not follow links or open files unless you are confident that this message is legitimate.<o:p></o:p></p>
<p><strong><span style="color:black;background:yellow">Caution:</span></strong>This message originated from outside of Aerodyne. Do not follow links or open files unless you are confident that this message is legitimate.<o:p></o:p></p>
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